Nuova ricerca

Michele LALLA

CULTORE DELLA MATERIA presso: Dipartimento di Economia "Marco Biagi"


Home | Curriculum(pdf) | Didattica |


Pubblicazioni

2020 - Democrazia versus governabilità [Articolo su rivista]
LALLA, Michele
abstract

Le organizzazioni politiche post ideologiche, come il Movimento Cinque Stelle (M5S), sono caratterizzate da una debole coesione interna e una identificazione con il capo. Il cambio di maggioranza, avvenuto dopo la caduta del governo Conte I, ha provocato la fuoriuscita di diversi parlamentari del M5S, sulla quale occorre riflettere, e ha indotto Luigi di Maio a richiedere nuovamente il vincolo di mandato, invocato per ridurre il trasformismo, ossia il cambio di partito dei parlamentari. Come è noto, il rimedio è anticostituzionale, ma rischia comunque di essere peggiore del male, perché il parlamentare può essere piú facilmente eterodiretto dal capo vanificando la sua funzione di rappresentante; inoltre, per quanto sembri paradossale, anche la libertà di cambiare partito deve essere garantita, perché il partito stesso può tradire le promesse fatte agli elettori. Se si considera, poi, che la legge di riduzione dei parlamentari, è in corso di approvazione, presumibilmente senza intoppi, allora la situazione diventa ancóra piú preoccupante, perché produce effetti convergenti con il vincolo di mandato sullo spostamento della centralità dalla democrazia e, quindi rappresentanza, alla governabilità con il conseguente indebolimento della prima, ossia della democrazia.


2020 - Il piano di campionamento dell’indagine sulla alta affidabilità organizzativa [Capitolo/Saggio]
Lalla, M.
abstract

Il capitolo descrive la procedura del piano di campionamento adottata per l’indagine, descrivendo tutti i passi seguíti: la determinazione della dimensione campionaria, la stratificazione per azienda e per la posizione professionale degli addetti, la costruzione della lista per strato e la selezione delle unità tramite il campionamento sistematico. Illustra, quindi, gli esiti della rilevazione campionaria e, come nella tradizione, i fattori di riporto alla popolazione obiettivo, le formule relative alle varianze delle stime, e qualche cenno agli errori non campionari.


2020 - Metodologia e strumenti di indagine: il questionario sull’alta affidabilità organizzativa [Capitolo/Saggio]
Lalla, M.; Pistolesi, E.
abstract

Il capitolo descrive le analisi preliminari svolte e la metodologia seguita per la costruzione del questionario sulla alta affidabilità organizzativa. Le analisi preliminari, di natura logico-semantica e statistica, provengono da una ricerca precedente che aveva utilizzato il questionario di Weick e Sutcliffe riportato nella versione italiana del loro libro: Governare l’inatteso – Organizzazioni capaci di affrontare le crisi con successo, traduzione di F. Dovigo, Raffaello Cortina Editore, Milano, 2010. Per risolvere tutte le questioni individuate si è attuata una accurata revisione delle espressioni per semplificarle, controllando la loro leggibilità tramite Gulpease, realizzato nel 1988 dal GULP (Gruppo Universitario Linguistico Pedagogico) dell’Università di Roma “La Sapienza”, sotto la supervisione di Maria Corda Costa e Tullio De Mauro e in collaborazione con l’IBM Italia. Si riportano alcuni risultati salienti, ma, per questioni di proprietà del testo, non si riporta la nuova scala ottenuta con le sue nove sezioni, con un totale di ottantatré (83) domande. Si è valutata anche la presenza nel questionario di parole appartenenti al “Vocabolario di base”. La riformulazione delle domande ha perseguito comprensione e chiarezza conseguendo un risultato assai soddisfacente.


2020 - Nonresponse and measurement errors in income: matching individual survey data with administrative tax data [Working paper]
Lalla, M.; Cavicchioli, M.
abstract

A (local) survey on income carried out in the city of Modena in 2002 generated four categories of units: interviewees, refusals, noncontacts, and sometimes unused reserves. In this study, all units were matched with their corresponding records in the Ministry of Finance 2002 databases for fiscal incomes of 2001 and the 2001 Census. Considering all four categories, participation increased by education level and activity status, while it decreased among low or high incomes. Considering interviewees only, over- and under-reporting, as well as measurement errors, were investigated by comparing the surveyed income with fiscal income. Age and level of income were the main covariates affecting the behaviours of taxpayers.


2020 - Tertiary education decisions of immigrants and non-immigrants in Italy: an empirical approach [Working paper]
Lalla, M.; Frederic, P.
abstract

Decisions regarding tertiary schooling are important for young people as it affects future opportunities for employment and social mobility. Tertiary schooling also plays a role in the social integration of immigrants. To determine differences in the choices of young Italian natives and immigrants concerning education, two datasets for 2009 were used: European Union Statistics on Income and Living Conditions (EU-SILC) and the Italian Survey on Income and Living Conditions of Families with Immigrants in Italy (IT-SILCFI). Analysing a sub-sample of young Italians and immigrants, between 20 and 29 years of age, the association of both individual and family explanatory variables in the choice of secondary schooling (yes/no) was assessed using logistic models. The results show that young immigrants tend to interrupt their schooling earlier than their Italian peers. However, differences disappear when family background and parental characteristics are taken into account.


2019 - Comparative proteomic analysis between the gingival crevicular fluid and the corresponding periodontal pocket: a preliminary study [Articolo su rivista]
Bertoldi, Carlo; Bergamini, Stefania; Ferrari, Monica; Lalla, Michele; Bellei, Elisa; Spinato, Sergio; Tomasi, Aldo; Monari, Emanuela
abstract

Introduction The aim of this study was to compare the proteomic profile of periodontal pocket tissues with that of corresponding gingival crevicular fluid (GCF), and to search for similarities in their proteomic profile. Material and Methods Four patients suffering from moderate or severe chronic periodontitis, needing surgical periodontal treatment, were selected. Immediately before the periodontal surgery, GCF samples were taken by means of filter paper strips positioned in the gingival sulcus correspondent to periodontal pockets. Then, periodontal pocket tissue, harvested during surgery, was adequately stored for proteomic analyses. Results Using an image analysis software for proteomic data, we found almost the same protein expression profile in GCF and pocket tissue from each patient. Accordingly, in our patients we found no statistically significant correlation between the quantitative proteomic profile of GCF and pocket tissue. Only one band (that of K immunoglobulin) resulted statistically different between GCF and pocket tissue proteome in all patients (p=0.008). Conclusions The protein network of the periodontal pocket does not influence significantly the GCF protein network. The periodontal pocket and the GCF are similar as far as the proteomic networks are concerned, but the GCF does not seem suitable to study on the pathogenesis of periodontal disease.


2019 - Emergenza nel pensiero democratico [Articolo su rivista]
Lalla, M.
abstract

Le democrazie sono sempre in pericolo, ma oggi il rischio è accresciuto; perciò, è necessario aumentare la partecipazione alla vita sociale e educare e informare meglio i cittadini sui princípi democratici al fine di vaccinare le coscienze contro gli attacchi di bacilli inoculati con perfidia e diretti a indebolire le istituzioni democratiche. L’articolo delinea alcuni pericoli dei sistemi democratici, discutendo per esemplificazioni il vincolo di mandato, i limiti e la durata di mandato, la concentrazione delle funzioni in organismi quasi autocratici. L’obiettivo è promuovere una ampia attività maieutica, specialmente tramite i media, diretta a chiarire e diffondere i meccanismi fondanti della democrazia e a smascherare i pericoli delle soluzioni proposte spesso come la panacea dei mali correnti, ma che producono, in realtà, un peggioramento del sistema democratico.


2019 - Logica nell’argomentazione politica [Articolo su rivista]
Lalla, M.
abstract

Gli strumenti della logica sono quasi inapplicabili alle situazioni politiche sia perché tutte le informazioni non sono sempre disponibili sia perché le argomentazioni sono volte a fare propaganda, che è esclusa dalla logica giacché o le premesse o le conclusioni o entrambe sono errate. La perseveranza di chi ostinatamente confida nel raziocinio può condurre a qualche risultato apprezzabile, ma in molti casi l’incertezza delle conclusioni permane. A tal fine si esaminano i fatti agostani del 2019 che, nel giro di un mese, in un tumulto di colpi di scena, hanno condotto a un cambio di maggioranza assai radicale: si è passati dal governo Movimento Cinque Stelle (M5S) e Lega, detto gialloverde, al governo M5S e Partito Democratico (PD) con altri gruppi, detto giallorosso per semplicità, ma contiene diverse gradazioni di rosso fino al bianco. Si discutono sei tesi difensive/ accusatorie della Lega, mostrando le difficoltà a dirimere la verità o falsità delle proposizioni coinvolte nelle tesi. La logica risulta, cosí, depotenziata nelle argomentazioni politiche e altri coadiuvanti occorrono per orientarsi, i quali dipendono, però, dalle concezioni della società e delle regole comuni disciplinanti la convivenza, variabili da soggetto a soggetto: le preferenze passano dall’autoritarismo, in via di elevata diffusione, all’anarchismo. La cooperazione è la via piú proficua.


2019 - Measurement errors and tax evasion in annual incomes: evidence from survey data matched with fiscal data [Working paper]
Lalla, M.; Mantovani, D.; Frederic, P.
abstract

Individual records, referred to personal interviews of a survey on income carried out in Modena during 2012 and tax year 2011, had been matched with their corresponding records in the Ministry of Finance databases containing the fiscal incomes of tax year 2011. The analysis of the resulting data set suggested that the fiscal income was generally more reliable than surveyed income, but in the literature the exact opposite is often assumed. Moreover, the obtained data set enables identification of the factors determining over- and under-reporting, as well as measurement error, through a comparison of the surveyed income with the fiscal income, only for suitable categories of interviewees: the taxpayers who are obliged to respect the law (the constrained sector), and taxpayers who have many possibilities to evade (the unconstrained sector). The percentage of under-reporters (67.3%) was higher than those of over-reporters (32.7%). Level of income, age, and education were the main regressors affecting the measurement errors and the behaviours of taxpayers. Estimations of tax evasion and the impacts of personal factors affecting it were carried out following different approaches. The average of individual propensity to tax evasion was 25.93% of the corresponding fiscal income. The potential total tax evaders were about 10%.


2018 - Are periodontal outcomes affected by personality patterns? A 18-month follow-up study [Articolo su rivista]
Bertoldi, Carlo; Venuta, Marco; Guaraldi, Gianpaolo; Lalla, Michele; Guaitolini, Stefania; Generali, Luigi; Monzani, Daniele; Cortellini, Pierpaolo; Zaffe, Davide
abstract

OBJECTIVES: This research aims to study the relationship between personality traits and periodontal clinical outcomes by taking into account the level of anxiety and depression, periodontal health and oral hygiene behaviour of patients affected with gingivitis or moderate periodontitis requiring periodontal therapy. MATERIAL AND METHODS: The periodontal data of 40 systemically healthy patients affected by gingivitis or moderate periodontitis were collected at baseline and 18 months later. The psychological variables, dental awareness and adherence intent of the patients were assessed through questionnaires, and only those patients that exhibited a higher degree of compliance were included in the study. The personality traits (cluster A: paranoid, schizoid, schizotypal; cluster B: borderline, antisocial, narcissistic, and histrionic; cluster C: avoidant, dependent, and obsessive-compulsive) and the level of anxiety and depression of the patients were assessed. Patients were instructed with oral hygiene measures and were treated with periodontal therapy. RESULTS: Clusters A and B showed a consistent tendency for reduced levels of oral hygiene (increased full-mouth plaque score - FMPS). The results from cluster B were found to be significantly related to deep periodontal pockets at baseline. On the contrary, cluster C seemed to be linked to clinically better indices, particularly in terms of full-mouth-bleeding-score and pocket depth, both at baseline and 18 months later. The results collected from clusters B and C were directly correlated with anxiety, depression and FMPS. Moreover, anxiety was directly correlated with the patient's need for professional oral-care. CONCLUSIONS: Personality traits appear to play a significant role in determining the therapeutic outcomes of periodontal therapy in themselves. Thus, it is ideal for several important psychological, affective or behavioural factors to be associated with various personality traits so as to orient the outcome of periodontal therapy.


2018 - L’aliquota unica (flat tax): osservazioni sulla progressività [Articolo su rivista]
Lalla, M.
abstract

L’aliquota unica, da anni oggetto di programmi e propaganda elettorale, è esaminata sotto il profilo costitutivo e costituzionale, considerando la sostanza piuttosto che la forma, viste da un cittadino comune, ossia senza competenze tecniche specifiche, con una riflessione sulla semplificazione.


2017 - Fundamental characteristics and statistical analysis of ordinal variables: a review [Articolo su rivista]
Lalla, Michele
abstract

The measurement of several concepts used in social sciences generates an ordinal variable, which is characterized by rawness of the output values and presents some much debated problems in data analysis. In fact, the need for effective analysis is easily satisfied with parametric models that deal with quantitative variables. However, the peculiarities of the ordinal scales, and the crude values produced by them, limit the use of parametric models, which has generated conflicting favourable and unfavourable views of the parametric approach. The main distinctive features of ordinal scales, some of which are critical points and nodal issues, are illustrated here along with the construction processes. Among the traditional procedures, the most common ordinal scales are described, including the Likert, semantic differential, feeling thermometers, and the Stapel scale. A relative new method, based on fuzzy sets, can be used to handle and generate ordinal variables. Therefore, the structure of a fuzzy inference system is exemplified in synthetic terms to show the treatment of ordinal variables to obtain one or more response variables. The nature of ordinal variables influences the interpretation and selection of many strategies used for their analysis. Four approaches are illustrated (nonparametric, parametric, latent variables, and fuzzy inference system), highlighting their potential and drawbacks. The modelling of an ordinal dependent variable (loglinear models, ordinary parametric models or logit and probit ordinal models, latent class models and hybrid models) is affected by the various approaches.


2017 - How Intraday Index Changes Influence Periodontal Assessment: A Preliminary Study [Articolo su rivista]
Bertoldi, Carlo; Forabosco, Andrea; Lalla, Michele; Generali, Luigi; Zaffe, Davide; Cortellini, Pierpaolo
abstract

It is reputed that periodontal indices remain unchanged over a 24-hour period, with great clinical significance. This preliminary study analyzes daily index changes. In 56 selected patients, full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS), periodontal screening and recording (PSR) indices, and periodontal risk assessment (PRA) were recorded at baseline and three times per day (check-I: 08.30, check-II: 11.30, and check-III: 14.30), after appropriate cause-related therapy. Correlation between variables was statistically analyzed by Stata. All periodontal indices improved at the examination phase. Statistical differences were detected for FMPS comparing all thrice daily checks. Statistical differences were detected for FMBS and PRA comparing check-III with check-I and check-II. PSR showed no significant changes. The worst baseline indices produced the widest daily fluctuation at the examination phase. Significant variation of indices is directly related to clinical severity of periodontal conditions at baseline. Patients affected by severe periodontal disease may show significantly greater index changes. As indices are routinely recorded only once per day, the index daily variation has clinical significance. This greatly affects therapeutic strategy as correct periodontal assessment requires multiple evaluations at standardized times, particularly when baseline conditions are severe.


2017 - The personality traits, anxiety and depression, produce different periodontal outcomes: a 18-month follow-up study [Abstract in Rivista]
Bertoldi, Carlo; Generali, Luigi; Ferrari, M; Lalla, Michele; Venuta, Marco; Consolo, Ugo
abstract

Aim: Psychological attitude, depression, anxiety and oral hygiene on oral health have been recorded and correlated in subjects with untreated periodontal conditions. Methods: Periodontal data of forty systemically healthy-patients, affected by moderate periodontitis, were collected at baseline and 18 months later. The dental belief (DBQ) was self-administered to patients: a health-value scale (HV); two adherence-intent scales (AI1, AI2), were scored separately. The psychological variables were assessed by questionnaires administered by one expert operator. Personality traits were grouped into cluster including all the personality traits (cluster-A: paranoid, schizoid, schizotypal; cluster-B: borderline, antisocial, narcissistic, histrionic; cluster-C: avoidant, dependent, obsessive-compulsive) anxiety and depression were also assessed. Patients were instructed to oral hygiene measures, treated with cause-related therapy and with adjunctive surgical therapy, when needed. Data were expressed as mean ± standard deviation (m±SD). The comparisons were performed by nonparametric tests, Spearman correlation coefficients between variables were calculated and the relationships between the dependent variables and the independent ones were examined through the standard multiple regression models. The alpha Cronbach reliability coefficient for each HV, AI1 and AI2 scales was calculated by the item analysis procedure of Stata. The level of significance of the applied tests was the standard value P=0.05. Statistical analysis was performed by Stata, version 14.00. Results: Cluster-A and B showed a consistent tendency for reduced levels of oral hygiene (increased full-mouth-plaque-score -FMPS), independently by therapy and supportive periodontal therapy scheme applied. This effect appeared particularly enhanced in correlation with poorly compliant attitude and unfavorable baseline dental indices. On the contrary, cluster-C seemed to be linked to clinically better indices, particularly in terms of full-mouth-bleeding-score (FMBS) and pocket depth. Anxiety resulted directly correlated with depression, cluster-B and C, but inversely with FMPS and the patient’s requirement for professional oral-care. Additionally, depression was directly correlated with FMBS. Conclusions: Anxiety and depression, both affective disturbances, have a reciprocal link, and opposite effect on plaque and bleeding score. Personality traits (stable throughout life) play a significant role in periodontal condition and therapy outcomes that are not entirely ascribable to the lack of observance of oral hygiene rules, since study design and statistical analysis take in account also hygienic and behavior parameters. The knowledge of psychological traits of patients but also of anxiety and depression score, could greatly improve periodontal treatment outcomes.


2016 - The ordinal controversy and the fuzzy inference system through an application and simulation to teaching activity evaluation [Capitolo/Saggio]
Lalla, Michele; Pirotti, Tommaso
abstract

The handling of ordinal variables presents many difficulties in both the measurements phase and the statistical data analysis. Many efforts have been made to overcome them. An alternative approach to traditional methods used to process ordinal data has been developed over the last two decades. It is based on a fuzzy inference system and is presented, here, applied to the student evaluations of teaching data collected via Internet in Modena, during the academic year 2009/10, by a questionnaire containing items with a four-point Likert scale. The scores emerging from the proposed fuzzy inference system proved to be approximately comparable to scores obtained through the practical, but questionable, procedure based on the average of the item value labels. The fuzzification using a number of membership functions smaller than the number of modalities of input variables yielded outputs that were closer to the average of the item value labels. The Center-of-Area defuzzification method showed good performances and lower dispersion around the mean of the value labels.


2015 - Le scale ordinali e i relativi problemi operativi [Capitolo/Saggio]
Lalla, Michele
abstract

La misurazione di numerosi concetti utilizzati nelle ricerche sociali genera una variabile ordinale, che presenta alcuni problemi nell’analisi dei dati tuttora discussi. La genesi delle problematicità deriva dal processo di misura, che colloca le variabili ordinali nella classe delle qualitative, e si acuisce nel contrasto tra le esigenze di analisi efficaci, che si ottengono facilmente con modelli che trattano variabili quantitative, e le peculiarità delle scale ordinali che limitano il loro uso. I principali aspetti distintivi delle scale ordinali, alcuni dei quali costituiscono i punti critici e nodali delle questioni, sono qui illustrati assieme ai procedimenti di costruzione che, oltre a quelli tradizionali, contemplano anche quello basato sugli insiemi sfocati. Nel primo caso si descrivono le piú diffuse scale ordinali: Likert, differenziale semantico, termometri di sentimenti, e Stapel. Nel secondo caso si presenta in termini sintetici la struttura di un sistema di inferenza sfocata per il trattamento di variabili ordinali al fine di ottenere una o piú variabili risposta.


2015 - Managing the unexpected: A case study on the management practice and perceptions [Relazione in Atti di Convegno]
Golzio, Luigi Enrico; Lalla, Michele
abstract

The measurement of the attitude of individuals about the concepts involved in mindfulness was carried out through nine scales proposed by Weick and Sutcliffe (2001, 2007), each one of which being constituted by a different number of items, ranging from seven to twelve items. Seven scales out of nine contained ordered response categories such as “1 = not at all”, “2 = to some extent”, and “3 = a great deal”. The two remaining scales (the 3rd and the 6th) had a binary set of options as response categories: “agree” or “disagree”. The questionnaire containing the nine scales was administered to four establishments of a selected firm, with 103 respondents. The evaluation of each score for each section, classified in three categories (Low, Median, and Optimal), followed different criteria: location with respect to the corresponding thresholds, and the concentration and dispersion of scores in the optimal category. The evaluation of the performance of each scale was carried out considering: its internal consistency through the Cronbach’s alpha, the distribution of the scores in response categories with respect to the direction of the scale, and semantic analysis of items to ascertain coherence with the polarity of the scale. The data analysis revealed some critical items in various sections and suggested the need for further studies and applications to ascertain their foundation, stability, and robustness. Another observation concerned a different set of options for the items: a self-anchoring Likert scale for the sections S1, S2, S4, S5, and S7-S9 (e.g.: «1=not at all, 2, 3, 4, 5=a great deal»), and a classical Likert scale for sections S3 and S6 (2=totally disagree, 1=disagree, 0=neutral, +1=agree, +2=totally agree)


2015 - School enrollment of first- and second-generation immigrant students in Italy: a geographical analysis [Articolo su rivista]
Bertolini, Paola; Lalla, Michele; Pagliacci, Francesco
abstract

This paper analyses non-compulsory secondary school enrolment of immigrant students in Italy. Such enrolment implies a voluntary decision and can influence future career paths in the labour market. The results show that the enrolment rates of immigrants are lower than those of Italians. Immigrant students prefer vocational schools and shorter-term education. The pattern of these preferences remains constant across the throughout Italy, even if Italy presents strong differences in the economic development of its regions, with rich Northern and poor Southern regions. The enrolment rates of second-generation immigrant students differ from those of first-generation students, but the size of this component is still too small to indicate a clear trend.


2014 - Fuzzy Inference System to Analyze Ordinal Variables - The Case of Evaluating Teaching Activity [Relazione in Atti di Convegno]
Lalla, Michele; Ferrari, Davide; Pirotti, Tommaso
abstract

The handling of ordinal variables presents many difficulties in both the measurements phase and the statistical data analysis. Many efforts have been made to overcome them. An alternative approach to traditional methods used to process ordinal data has been developed over the last two decades. It is based on a fuzzy inference system and is presented, here, applied to the student evaluations of teaching data collected via Internet in Modena, during the academic year 2009/10, by a questionnaire containing items with a four-point Likert scale. The scores emerging from the proposed fuzzy inference system proved to be approximately comparable to scores obtained through the practical, but questionable, procedure based on the average of the item value labels. The fuzzification using a number of membership functions smaller than the number of modalities of input variables yielded outputs that were closer to the average of the item value labels. The Center-of-Area defuzzification method showed good performances and lower dispersion around the mean of the value labels.


2014 - Managing the unexpected: A case study [Articolo su rivista]
Golzio, Luigi Enrico; Lalla, Michele; Manni, MARIA GIOVANNA
abstract

The measurement of the attitude of individuals about the concepts involved in mindfulness was carried out through nine scales proposed by Weick and Sutcliffe (2001, 2007), each one of which being constituted by a different number of items, ranging from seven to twelve items. Seven scales out nine contained ordered response categories such as “1 = not at all”, “2 = to some extent”, “3 = a great deal”. The two remaining scales (the 3rd and the 6th) had a binary set of options as response categories: “agree” or “disagree”. The questionnaire containing the nine scales was administered to four establishments of a selected firm, with 103 respondents. The evaluation of each score for each section, classified in three categories (Low, Median, and Optimal), followed different criteria: location with respect to the corresponding thresholds, and the concentration and dispersion of scores in the optimal category. The evaluation of the performance of each scale was carried out considering: its internal consistency through the Cronbach’s alpha, the distribution of the scores in response categories with respect to the direction of the scale, semantic analysis of items to ascertain coherence with the polarity of the scale. The data analysis revealed some critical items in various sections and suggested further studies and applications to ascertain their foundation, stability, and robustness. Another observation concerned a different set of options for the items: a self-anchoring Likert scale for the sections S1, S2, S4, S5, and S7-S9 (e.g.: «1=not at all, 2, 3, 4, 5=a great deal»), a classical Likert scale for sections S3 and S6 (2=totally disagree, 1=disagree, 0=neutral, +1=agree, +2=totally agree).


2014 - Mean and variance of non-normal fuzzy numbers and fuzzy quantities [Articolo su rivista]
Lalla, Michele; Pacchiarotti, Nicoletta
abstract

The concept of mean is extended to non-normal fuzzy numbers and its properties (internality, zero-sum deviation, crispness, invariance, and associativity) are illustrated thoroughly. Analogously, the notion of variance is extended to non-normal fuzzy numbers and its properties (positivity, zero-variance, invariance, change of pole) are reported together with the relationships between two different definitions of variance and different poles. In particular, we demonstrate inequalities between variances of the same fuzzy set with respect to different poles. Finally, the variance is defined for the union of fuzzy sets.


2014 - The secondary education choices of immigrants and non-immigrants in Italy [Articolo su rivista]
Lalla, Michele; Pirani, E.
abstract

The choice of secondary schooling, which is not compulsory in Italy, is important for youths because it affects future opportunities for employment and social mobility. Secondary schooling also plays a role in the social integration of immigrants. To ascertain the presence of differences between young Italian natives and immigrants in education choices, two datasets for 2009 were used: the European Union Statistics on Income and Living Conditions (EU-SILC) and the Italian Survey on Income and Living Conditions of the Families with Immigrants in Italy (IT-SILCFI). Analysing a sub-sample of young Italians and immigrants, aged between 16 and 19 years old, the association of both individual and family explanatory variables with the choice of secondary schooling (yes, no) was assessed using logistic models. The main results show that young immigrants tend to interrupt their schooling earlier than their Italian counterparts. However differences disappear when family background and parental characteristics are accounted for.


2013 - Il modello di prevenzione ad alta affidabilità per la gestione delle crisi: la consapevolezza nella gestione dei rischi in uno studio di caso [Working paper]
Golzio, Luigi Enrico; Lalla, Michele; Manni, MARIA GIOVANNA
abstract

The measurement of the attitude of individuals about the concepts involved in mindfulness was carried out through nine scales proposed by Weick and Sutcliffe (2001, 2007), each one of which being constituted by a different number of items, ranging from seven to twelve items. The questionnaire containing the nine scales was administered to four establishments of a selected firm, with 103 respondents. The evaluation of each score for each section, classified in three categories (Low, Median, and Optimal), followed different criteria: location with respect to the corresponding thresholds, and the concentration and dispersion of scores in the optimal category. The evaluation of the performance of each scale was carried out considering: its internal consistency through the Cronbach’s alpha, the distribution of the scores in response categories with respect to the direction of the scale, semantic analysis of items to ascertain coherence with the polarity of the scale. The data analysis revealed some critical items in various sections and suggested further studies and applications to ascertain their foundation, stability, and robustness. Another observation concerned a different set of options for the items: a self-anchoring Likert scale for the sections S1, S2, S4, S5, and S7-S9, a classical Likert scale for sections S3 and S6.


2013 - Internship effectiveness evaluation by students and firms: A year of experience at the Faculty of Economics in Modena [Articolo su rivista]
Lalla, Michele; Bursi, Tiziano; Maccagnan, Anna
abstract

Internship programmes organised by the Faculty of Economics at Modena are evaluated through two questionnaires: one for students and another for firms. The data collected over 2009, separately for students and firms, were subsequently matched. The data analyses showed that the internal homogeneity of the item batteries and of their dimensions – semantically derived from the questionnaire items – was satisfactory. The factors obtained through an exploratory factor analysis did not prove to correspond perfectly to these dimensions for students, while they did correspond in the case of firms. The identification of the determinants of effectiveness, measured through the internship evaluation provided by students and firms, was carried out through a logistic regression and a structural equation model.


2013 - Risk factors and socioeconomic condition effects on periodontal and dental health: a pilot study among over 50 [Articolo su rivista]
Bertoldi, Carlo; Lalla, Michele; Pradelli, J. M.; Cortellini, P.; Lucchi, A.; Zaffe, Davide
abstract

Objective: Observational studies on the association among systemic / general and oral cavity indices, tooth loss, periodontal conditions, and socioeconomic inequalities are to be still performed in the population of Southern Europe. This study aims to determine the extent of this relationship among Italian healthy adults 50 years of age and above. Materials and Methods: Socioeconomic and lifestyle characteristics, cardiovascular indicators, and systemic indices were examined by contrasting the dental indices among adult people of Northern Italy. Data were processed through correlation analysis, and multivariate analysis was carried out using seemingly unrelated regressions. Results: A total of 118 adults 50 years of age and above were anamnesed and underwent systemic 50 years of age and above, after anamnesis, underwent systemic and dental examination. Their socioeconomic status was found to be inversely associated only with smoking and dental parameters. Unexpected outcomes between lifestyle and risk factors were detected. The statistical analysis showed an uneven correlation among dental indices and between those indices and the socioeconomic status, such as, a periodontal condition, apparently free from influences, unusually became worse as class was enhanced. became worse as the socioeconomic status enhanced.Conclusions: The study outcomes indicate a relationship between tooth loss and conservative endodontic therapy, but they result in alternative choices. Nevertheless, the socioeconomic status has an inverse relationship with tooth loss and conservative endodontic therapy, but a direct relation with worsening of the periodontal condition. This pilot study highlights a need for the public health administration to adopt a socioeconomic assessment not only based on the household income, but also to accordingly improve its therapeutic course.


2012 - Herpes Simplex I virus impairs regenerative outcomes of periodontal regenerative therapy in intrabony defects. A pilot study [Articolo su rivista]
Bertoldi, Carlo; Pellacani, Chiara; Lalla, Michele; Consolo, Ugo; Pinti, Marcello; Cortellini, P.; Cossarizza, Andrea
abstract

Aim: To evaluate the impact of herpesvirus type-1 and -2 on the clinical outcomes of periodontal regenerative procedures in isolated deep intrabony pockets, in an experimental population with no detectable periodontal pathogens. Materials and Methods: Seventeen periodontal intraosseous defects in 17 moderate- to-advanced periodontitis patients were treated with regenerative therapy and amelogenins. Microbiological evaluation was performed at baseline (after the completion of initial therapy) and at 1 year to exclude the presence of periodontal pathogens. Herpesviruses-1 and -2 DNA were quantified in the pocket tissues associated to the intrabony defect using molecular assays. Clinical attachment level (CAL), probing pocket depth (PPD) and gingival recession (REC) were recorded at baseline and at 1 year. Results: After 1 year, the 17 defects resulted in significant CAL gain, PPD reduction and REC increase. HSV-1 was detected in five patients. Herpesvirus-2 was never found. The two subpopulations positive or negative to herpesvirus-1 were homogeneous at baseline. At 1 year, the five herpesvirus-1 positive patients resulted in lower amounts of CAL-gain and PPD reduction and greater amount of REC with respect to the 12 herpesvirus-1 negative patients. Conclusions: The presence of herpesvirus-1 at baseline is associated with poor clinical outcomes following regenerative therapy. PMID: 22292785 IDS Number: 907NW


2012 - Immigrant Inclusion and Prospects through Schooling in Italy: An Analysis of Emerging Regional Patterns [Capitolo/Saggio]
Bertolini, Paola; Lalla, Michele
abstract

The paper analyses immigrants’ school participation form pre-mandatory school to secondary school in Italy, with a particular regard to secondary schools, because schooling at this level is not compulsory, implying a voluntary decision, and is an indirect indicator of social mobility. The data show that the percentages of foreign repeaters (with a value of 8.5%) in the mandatory middle school are greater than those of Italian students (3.2%). The participation rates of immigrants in high school are lower than those of young Italians. Immigrant students prefer vocational schools and shorter-term education. The pattern of these preferences remains constant across the territory. The behavior of immigrants born in Italy is different from that of the first generation and more similar to that of Italian students. This convergence may indicate a positive integration process.


2012 - L’inserimento scolastico e lavorativo degli immigrati [Capitolo/Saggio]
Bertolini, Paola; Lalla, Michele
abstract

This paper analyses non-compulsory secondary school enrolment of immigrant students in Italy, through the seemingly unrelated regressions model, containing ten equations. Moreover, it presents also an analysis of the school participation by areas obtained through an aggregation of provinces, considering their homogeneity with respect to the value added in the three standard sectors: agriculture, industry, and services. The enrolment in secondary schools implies a voluntary decision and can influence future career paths in the labour market. The results show that the enrolment rates of immigrants are lower than those of Italians. Immigrant students prefer vocational schools and shorter-term education. The pattern of these preferences remains constant across the throughout Italy, even if Italy presents strong differences in the economic development of its regions, with rich Northern and poor Southern regions. The enrolment rates of second-generation immigrant students differ from those of first-generation students, but the size of this component is still too small to indicate a clear trend.


2012 - The fluctuation of periodontal indexes during the same day: a pilot study. [Abstract in Rivista]
Bertoldi, Carlo; Caprara, G.; Ponzini, V.; Forabosco, Andrea; Lalla, Michele; Lucchi, A.; Simonazzi, L.; Guaitolini, S.; Pellacani, C.; Bertoldi, C.
abstract

Aim: This was to determine if periodontal indexes, from which we choose the periodontal therapy, can be influenced by the time of day they are collected. Material and Methods: Using specific inclusion and exclusion criteria, we enrolled 21 patients. The study involved the comparison of the full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS) and periodontal screening and recording (PSR) index in three successive stages of the same day, (8.30-T1, 11.30-T2, 14.00-T3) during the maintenance phase. Oral status of the patients and lifestyle were also considered. Results: Comparing T1, T2 and T3 it can be seen that the FMBS was significantly different in each phase: T1 (m ± SD 9,17 ± 6,61), T2 (6,95 ± 6,50) and T3 (5,77 ± 5,95). T1-PSR (0,91 ± 0,21) was greater than T2 (0,81 ± 0,26) and T3 (0,80 ± 0,25). The evaluation differential resulted positively conditioned by the number of teeth with a negative prognosis (NPT) for PSR and for females for FMPS. The NPT affected the PSR negatively and the FMPS and FMBS positively. Years of smoking and the number of cigarettes per day affected the FMPS and FMBS negatively whilst being a smoker clinically improved the FMPS and FMBS. Conclusion: The FMBS and PSR show significant fluctuation during the day. In order to achieve more reliable data of the indices, multiple recordings during the day should be taken. The NPT and smoking are able to influence, in a complicated way, the periodontal indices and their fluctuations. Abstract N P0229 ISSN:1600-051X (Electronic)


2012 - Unit nonresponse errors in income surveys: A case study [Articolo su rivista]
Lalla, Michele; Ferrari, Davide; Frederic, Patrizio
abstract

A survey on the economic and social conditions of households in the city of Modena was carried out in 2002 and in 2006 (two waves) by the CAPP (Centre for Analyses of Public Policies). In first wave of 2002, each designated sampling unit (i.e., the family) had three units as reserves. If the first refused to be interviewed, the interviewer contacted the three reserves, one after the other, until obtaining either one respondent or four non-participant units. At the end of the survey four categories of units were distinguished: interviewees, refusals, noncontacts, and unused reserves. All units were matched with their corresponding record in the databases of the Ministry of Finance of 2002 and the Census of 2001. The resulting data set permitted the analysis of unit or total nonresponses. The distribution of fiscal income showed different shapes for the four categories, implying a selective participation of the families. The interviewees yielded a positive bias of about 600€, holding constant other factors. The selection of the significant factors affecting nonresponse was performed via backward elimination in a logit model and with the lasso method. Participation increased as fiscal income and age increased and by education level (secondary school and university degree), while it decreased among entrepreneurs, independent workers, managers, and medium-to-low skilled workers.


2012 - VARIATION OF PERIODONTAL INDEXES DURING THE SAME DAY. [Abstract in Atti di Convegno]
Nechytaylo, A.; Melpignano, F.; Lalla, Michele; Forabosco, Andrea; Giannetti, Luca; Consolo, Ugo; Bertoldi, Carlo
abstract

Vedi allegato


2011 - Students’ Evaluation of Teaching Effectiveness: Satisfaction and Related Factors [Capitolo/Saggio]
Lalla, Michele; Frederic, Patrizio; Ferrari, Davide
abstract

The relationship between students’ attitude towards teaching evaluation and the success of a teaching evaluation procedure has been frequently investigated in education sciences. Nevertheless, accurate studies of the factors driving the rating are relatively rare. The present paper deals with the determinants of students’ satisfaction and teachers’ evaluation. Students’ satisfaction and the clarity of lectures were analysed using a 15-item evaluation questionnaire based on a 4-point Likert scale, 9-dichotomous observations in addition to student, teacher, and course characteristics. The data were collected three weeks before the end of each term from all the classes in business and economics taught during the academic year 2006/2007 at the University of Modena and Reggio Emilia. The chosen collection method was an internet survey, i.e., the questionnaires were filled by students via internet on voluntary participation base. The study was carried out for students seeking a degree in economics. Note that such a degree represents an interesting case study due to the presence of a variety of subjects, including history, sociology, mathematics, statistics, economics, business, law, and foreign languages. Switching from the traditional in-class paper survey to the internet survey: (i) increased the number of evaluated courses and (ii) decreased the number of participating students. In order to reduce the sample size effect on the variables referred to teacher and class, we considered evaluations for classes with more than five responding students. The total sample size turned out to be of n=4111 responding students. Almost all evaluation items showed a positive impact on both student satisfaction and clarity of teacher’s presentation. Instructors teaching foreign languages proved to be clearer than those in other subjects. When clarity of teacher’s presentation was considered as a response, the hypothesis of the same-sex-preference appeared to be supported by data. The class size exhibited a nonlinear relationship with students’ satisfaction, where the medium size was found to be optimal. Schools and subjects impacted differently on the dependent variables.


2011 - Web-based versus paper-based data collection for the evaluation of teaching activity: empirical evidence from a case study [Articolo su rivista]
Lalla, Michele; Ferrari, Davide
abstract

The collection of teaching evaluation questionnaires in the traditional paper-and-pencil format is a costly and time consuming process and yet it is a common assessment practice in many university systems. Web-based data collection would reduce costs and significantly increase the efficiency of the overall evaluation process in numerous ways. Results for both types of surveys are reported from two years of progressive introduction of the Web-based survey by the University of Modena and Reggio Emilia, Italy. In the first year, two faculties representing scientific and humanistic fields were selected for a Web-based survey. In the second year, eight out of twelve faculties took part in the Web survey. This data collection strategy allowed for responses from non-attending students and facilitated a comparison of attitudes between attending and non-attending students.


2010 - I patterns territoriali nell’inserimento scolastico degli studenti stranieri di prima e seconda generazione [Articolo su rivista]
Bertolini, Paola; Lalla, Michele; Toscano, Valentina
abstract

The analysis focuses on the immigrants’ school participation in the secondary school, considering also the first and the second generation. The data has been extracted from official statistical databases, mainly of the Ministry of Education and Istat (Italian National Statistics Institute). The analysis points out that the participation rates of foreign students in the secondary school are lower than those of the Italian students and both of them are different among regions and provinces. A multivariate analysis by territorial areas reveals that the main factors affecting the education choices are related to the local characteristics and the economic variables, such as total families’ income and gross national product (GNP) per capita. These results suggest that the immigrant students face with many difficulties in educational attainment preferring a fast entrance in the labour market.


2010 - Il piano di campionamento dell’indagine [Icesmo2] [Capitolo/Saggio]
Lalla, Michele
abstract

This chapter describes the survey and sample designs adopted to carry out the second occasion of the income survey in province of Modena. Specifically, it illustrates the determination of the sampling size, the territorial stratification, the selection of sampling units, the calculation of weights, the variance of estimators, post-stratification weights, the key-points of an income longitudinal survey, some indicators of total and partial nonresponses. It is a synthetic version of a previous paper (Lalla 2005).


2010 - La componente longitudinale a Modena [Capitolo/Saggio]
Colombini, Sara; Lalla, Michele
abstract

This chapter analyzes the longitudinal panel data of the income survey in province of Modena, the comparison between the first and the second wave. Specifically, it illustrates the coherence of the panel sample with the target population, the net variation of the individual income, and the gross change, i.e., the individual variation of the income. Moreover, the inequalities and poverty are analyzed to ascertain the determinants.


2010 - L’inserimento scolastico degli studenti stranieri di prima e seconda generazione in Italia [Working paper]
BERTOLINI, Paola; LALLA, Michele; TOSCANO, VALENTINA
abstract

The aim of the paper is the analysis of the immigrants' school insertion paths in Italy. The analysis focuses on the immigrants' school participation in the secondary school, considering also the first and the second generation. The data has been extracted from official statistical databases, mainly of the Ministry of Education and Istat (Italian National Statistics Institute). The analysis points out that the participation rates of foreign students in the secondary school are lower than those of the Italian students and both of them are different among regions and provinces. Five territorial areas are distinguished through some social and economic indicators (sectoral added value and number of industrial districts) in order to show the determinants of different participation rates between foreign and Italian students. A multivariate analysis by territorial areas reveals that the main factors affecting the education choices are related to the local characteristics and the economic variables, such as total families' income and gross national product (GNP) per capita. These results suggest that the immigrant students face with many difficulties in educational attainment preferring a fast entrance in the labour market.


2009 - Analisi di rilevanza del riscontro intralesionale degli Herpes simplex virus nei risultati della terapia parodontale rigenerativa [Articolo su rivista]
Bertoldi, Carlo; Pellacani, C.; Pinti, Marcello; Lalla, Michele; Lucchi, A.; Zaffe, Davide; Consolo, Ugo; Cossarizza, Andrea
abstract

Lo scopo del presente studio è quello di indagare la presenza degli herpes simplex virus 1 & 2 (HSVs) nelle lesioni angolari parodontali ed analizzarne l’influenza nella finalizzazione in terapia chirurgica rigenerativa parodontale. Materiali e Metodi: Sono stati complessivamente valutati 7 pazienti di cui 5 di sesso femminile e 2 di sesso maschile, di età compresa tra i 22 e i 60 anni sistemicamente sani. Dopo decontaminazione causale e di eventuali altri siti patologici, venivano eseguite indagini microbiologiche in ogni paziente con tamponi per escludere uno specifico ruolo batterico o micologico nell’ambito dei casi trattati. Immediatamente prima dell’intervento, un test biomolecolare (Meridol® Perio Diagnostics), basato sulla tecnologia realt-time polymerase chain reaction (RT-PCR), è stato utilizzato in rapporto al difetto angolare su cui intervenire ed ai solchi circostanti per escludere la presenza di batteri sicuramente parodontopatogeni (la cui presenza avrebbe portato all’esclusione del paziente dallo studio; ad egli, comunque, sarebbe stata garantita l’assistenza necessaria al caso). Il sito veniva trattato mediante minimally invasive surgical technique (MIST) e con enamel matrix protein (EMP – Emdogain , Biora AB, Malmö, Sweden). Il connettivo infiammatorio patologico presente nel difetto angolare veniva asportato, veniva inserito in provetta sterile e refrigerato immediatamente a -20 C°. Tale prelievo, in seguito, veniva preparato per la fase biomolecolare di rilevazione virale mediante sonde per acidi nucleici e real-time polymerase chain reaction (RT-PCR). Durante tutto il periodo di follow-up quindi il paziente veniva mantenuto in terapia di mantenimento e tutte le diverse misurazioni (FMPS, FMBS, PPD, REC, CAL) erano compiute in singolo-cieco da uno stesso operatore. In particolare le misurazioni erano effettuate prima dell’intervento (fase T0), a 6 mesi dall’intervento (T1) ed a una anno (T2); il follow-up era quindi a 12 mesi. Pur essendo registrati i diversi indici parodontali necessari alla terapia, la PPD rappresentava la variabile finale principale misurabile. L’analisi biomolecolare era condotta mediante estrazione del DNA virale e tecnica RT-PCR, come precedentemente descritto (7). Risultati I valori di PPD raccolti a T1 indicavano un miglioramento (non statisticamente significativo) degli stessi difetti per 11 delle tasche parodontali prese in esame, con una riduzione della profondità media di 1,5 mm, mentre in 3 casi non si registrava alcun sensibile miglioramento. I dati raccolti a T2 (fine del periodo di follow-up) mostravano una riduzione statisticamente significativa della PPD di tutti i difetti parodontali analizzati in rapporto a T0 ed, in particolare, il miglioramento medio era di 5,5 mm in termini di PPD. In 3 difetti angolari, tuttavia, tale miglioramento era stato piuttosto scarso e la profondità di tali difetti, anche in seguito al trattamento chirurgico, risultava ancora non fisiologica, ovvero persisteva una tasca. Le indagini biomolecolari hanno evidenziato che 6 dei siti tra i difetti parodontali valutati, erano positivi all’infezione da HSVs (si può considerare l’infezione da HSVs significativa con valori ≥ di 10 copie di DNA appartenente a tale agente su 1000 cellule analizzate). Il confronto tra la presenza e la concentrazione di HSVs con la profondità del difetto parodontale misurato in T2 ha indicato che i casi con un più alta concentrazione di copie virali coincidevano con i difetti parodontali che non avevano presentato un miglioramento significativo dopo il trattamento chirurgico dello stesso. In fase T0 non si erano riscontrate differenze statisticamente significative in termini di PPD tra i siti infettati da HSVs ed i restanti. Si può osservare anche una associazione lineare positiva e significativa tra PPD in T1 e PPD in T0. Mediante l’analisi dei coefficienti di correlazione anche in scala logaritmica si è p


2009 - Studio longitudinale sul ruolo dei disturbi della personalità, di ansia e depressione nei risultati terapeutici conseguenti alla terapia parodontale causale in soggetti non parodontici [Articolo su rivista]
Bertoldi, Carlo; Guaitolini, S.; Venuta, M.; Lucchi, A.; Lalla, Michele; Veneziani, A.; Zaffe, Davide; Consolo, Ugo; Guaraldi, G.
abstract

Introduzione e scopo: L’insorgenza della parodontite è quanto meno facilitata se non dovuta alla presenza di fattori di rischio parodontali. Tra i fattori di rischi putativi (non comprovati ma presunti) di maggior interesse scientifico stanno quelli legati ai profili psicologico-comportamentali. Scopo del presente studio sarà quello di analizzare il ruolo dei fattori psicologici nell’insorgenza della parodontite. Materiali e metodi: 13 individui (4 di sesso femminile e 9 di sesso maschile) maggiorenni, sistemicamente e psichiatricamente sani, non affetti da malattia parodontale erano stati selezionati per lo studio. Il protocollo operativo comprendeva 4 fasi: visita, terapia causale, rivalutazione parodontale e terapia di mantenimento. Al soggetto, durante la prima fase, era richiesta la compilazione di un questionario di igiene-consapevolezza al fine di valutare la sua conoscenza delle procedure di igiene dentale domiciliare, professionale e di conoscere i procedimenti domiciliari da esso stesso portati in atto routinariamente. Venivan, inoltre, registrati il full-mouth bleeding score (FMBS), il full-mouth plaque score (FMPS) ed il peridontal screening and recording (PSR). Nel caso il paziente fosse incluso nello studio era richiesta anche la compilazione di 3 appositi test psicologici: diagnostic and statistical manual of mental disorders (DSM-SCID) – valutazione del tratto della personalità, il depression status inventory (DSI) ed il self-rating depression scale (SDS) per definire rispettivamente il grado di ansia e depressione del paziente. I pazienti erano quindi immessi interapia causale e seguiti per un follow-up complessivo di 18 mesi con rivalutazione degli indici parodontali ogni 3 mesi. Risultati: L’elaborazione dei dati mediante coefficienti di relazione hanno mostrato andamenti clinici favorevoli in coloro che maggiormente attuavano e conoscevano le procedure di igiene orale mentre tratti ansioso-depressivi si correlavano longitudinalmente a indici peggiori di FMPS me non di FMBS. Nello stesso tempo la valutazione multivariata degli indici ha indicato come ai disturbi ansiogeni o depressivi si sono ricavati risultati favorevoli in rapporto ai comportamenti igienici riferiti come attuati o da attuarsi e sfavorevoli in rapporto all’FMPS e, talora ai comportamenti igienici attuati con continuità. Conclusioni: Dai dati emersi dall’elaborazione di questo studio appare che le personalità ansiose e depressive attuano principalmente comportamenti igienici discontinui potenzialmente in grado di favorire l’insorgenza della malattia parodontale. Non si può, tuttavia, escludere in termini assoluti altre cause endogene legate alla mediazione della flogosi ed all’immunità.


2009 - Tax evasion and misreporting in income tax returns and household income surveys [Relazione in Atti di Convegno]
Baldini, Massimo; Bosi, Paolo; Lalla, Michele
abstract

This paper studies tax evasion and misreporting by comparing data from income tax files and a survey of household incomes, both relative to a medium-size Italian town. The novelty of our approach lies in the use of individual microdata, obtained by exact matching between the two data sources. As usual, the adopted proxy for tax evasion is the difference between survey income and tax-declared income. Our results lend support to the widely shared belief that in Italy the propensity to evade is higher among the self-employed. However, our findings do not bear out the existence, which emerged in previous studies, of a negative relationship between tax evasion and income levels. Underreporting seems to be concentrated in the lowest income deciles, while the level of tax evasion is higher at the top of the income distribution. Notwithstanding the reliability of the statistical base, our results must be accepted with caution, as the measure of tax evasion adopted is not able to make a clear distinction between evasion and misreporting


2008 - A Fuzzy Inference System for Teaching Evaluation [Relazione in Atti di Convegno]
Lalla, Michele; Ferrari, Davide; Pirotti, Tommaso
abstract

In Italian universities, the evaluations of teaching activity by students is mandatory and the National Committee for University System Evaluation proposed a questionnaire for class evaluation with items based on the four-point Likert scale relying on a traditional item-by-item analysis. In this paper, we propose a fuzzy inference system for analysing the data collected through this questionnaire for items with a four-point Likert scale. The scores based on the traditional procedure are comparable with the scores emerging from our fuzzy inference system.


2008 - Evaluation of Teaching Activity through the Internet and Non-Attending Students: The Experience of the University of Modena and Reggio Emilia [Relazione in Atti di Convegno]
Lalla, Michele; Ferrari, Davide
abstract

The collection of the evaluation questionnaires is costly and time consuming process. The use of internet in data collection, rather than completion on paper, will produce a cheaper and more efficient process. The two modes of administration were described through the results of two years of experimentation in the university of Modena and Reggio Emilia. In the first year, two faculties, representing the scientific and humanistic field, were selected: biosciences and biotechnologies, Economic and Communication Sciences. In the second year, eight faculties out of twelve participated to the experimentation. The adopted strategy allowed gathering information also about non-attending students. The different behaviours of the attending and non-attending student groups will be described in some details.


2008 - Vagueness evaluation of the crisp output in a fuzzy inference system [Articolo su rivista]
Lalla, Michele; Facchinetti, Gisella; Mastroleo, Giovanni
abstract

Fuzzy models generally provide an output characterised by vagueness, which is expressed through a solution fuzzy set. In many applications, the response of the model is transformed in a crisp value through some defuzzification methods for solution fuzzy region, thus losing its fuzziness. Only to preserve a few indications of its vagueness, some indices summarizing the spread of the output membership function could be used to associate them with the crisp output, such as its standard deviation, the quartile deviation, the coefficients of skewness and kurtosis. The behaviour of such indices is examined in a large number of possible, though unlikely, output solutions and in an application of a fuzzy inference system for evaluating university teaching activity. The results seem to suggest that the 20-80 mid-percentile range could be a good measure of the vagueness dispersion, while the coefficient of skewness could provide a useful indication about the asymmetry of the solution's shape. Moreover, a rough estimate of dispersion was obtained from a triangle approximating the solution fuzzy region because the results were straightforwardly deduced from formulae involving the abscissae of its vertices. The results generally appear to underestimate the true values of the standard deviations; the 15-85 mid-percentile range of the approximating triangle seemed to be a more suitable rough appraisal of fuzzy output dispersion.


2008 - Weibull regression of unemployment duration measured with error via the EM algorithm [Relazione in Atti di Convegno]
Ferrari, Davide; Frederic, Patrizio; Lalla, Michele
abstract

Several models aim to measure how demographic, professional, and labour market factors influence unemployment duration, which has a compelling social and economic interest. Nevertheless, this quest still appear challenging in both interpretations and solutions, due to various difficulties. Among others, a relevant issue is the accurate measurement of unemployment, which is often biased by the presence of unknown errors. In this paper, we consider the measurement error as a latent variable and derive an Expectation-Maximization (EM) algorithm in the context of aWeibull regression model. The proposed methodology allows to estimate at the same time: (i) the effect of the covariates of interest on unemployment duration and (ii) the measurement error.


2006 - Problemi e osservazioni sul questionario utilizzato per la valutazione della didattica da parte degli studenti frequentanti [Working paper]
LALLA, Michele
abstract

Student evaluations of teaching activity are compulsory in Italian universities and the National Committee for University System Evaluation (Comitato Nazionale di Valutazione del Sistema Universitario, CNVSU) proposed a course-evaluation questionnaire with items based on the four-point Likert scale and a traditional item-by-item analysis. This paper illustrates the main issues concerning the student evaluation of teaching, the survey and sample designs adopted to carry out the evaluation of the teaching activity, the wording of the proposed items, the timing of surveys because it could affect the results, and the advantages or disadvantages of the four-point Likert scale.


2005 - Il disegno della seconda indagine sulle condizioni economiche e sociali delle famiglie nella Provincia di Modena [Working paper]
LALLA, Michele
abstract

This paper describes the survey and sample designs adopted to carry out the second occasion of the income survey in province of Modena. Specifically, it illustrates the determination of the sampling size, the territorial stratification, the selection of sampling units, the calculation of weights, some results obtained from the previous occasion, the variance of estimators, post-stratification and calibration, the key-points of an income longitudinal survey, some indicators of total and partial nonresponses. Note: a previous paper (Lalla, 2003) reports the procedures adopted in the first occasion.


2004 - Appendix 2. The sampling strategy for the survey of households caring for elderly persons in the municipality of Modena [REPORT] [Altro]
Lalla, Michele
abstract

The Appendix describes the sampling design to identify and select households with a member providing care and help to an elderly person (aged 65 and over) who lived in the household, or lived in another dwelling, or was resident in protected housing.


2004 - Il piano di campionamento dell’indagine [Icesmo1] [Capitolo/Saggio]
Lalla, Michele
abstract

This chapter describes the survey and sample designs adopted to carry out the first occasion of the income survey in province of Modena. Specifically, it illustrates the determination of the sampling size, the territorial stratification, the selection of sampling units, the calculation of weights, the variance of estimators, post-stratification weights, the key-points of an income longitudinal survey, some indicators of total and partial nonresponses. It is a synthetic version of a previous working paper (Lalla 2003).


2004 - La preparazione degli studenti di Ingegneria e Economia dopo gli esami di matematica di base [Articolo su rivista]
Fiori, Carla; Lalla, Michele; Pacchiarotti, Nicoletta
abstract

Mathematics represents the basic language for all quantitative disciplines, therefore its learning is fundamental in many fields and it is interesting to verify how basic concepts may be lost as time passes. We carried out a survey between students attending courses of the third year and over, in the Faculty of Engineering and in the Faculty of Economics, assigning them a test containing items about the elementary concepts of Mathematics. The results show that students in the Faculty of Engineering know the mathematical concepts better than those in the Faculty of Economics. However, considering the differences between the two Faculties, the gap is lower than what appears from the outcomes of the test. The structure of the model representing the influences of the explanatory variables on the outcome of the test (score test) is similar in the two Faculties. In particular, the more predictive factors are the high school score and the number of Mathematics exams already passed at the University. The time elapsed since the last Mathematics exam does not show any peculiar influence on the test score. However, at the Faculty of Engineering, there was a weak concurrent action of this time with other variables, which incorporate its influence. The correlation between the time elapsed since the last Mathematics exam and the score of the test was always negative, as expected.


2004 - La preparazione degli studenti di Ingegneria e Economia dopo gli esami di matematica di base [Working paper]
FIORI, Carla; LALLA, Michele; PACCHIAROTTI, Nicoletta
abstract

The study of mathematics is essential in many fields as it is the basic language shared by all quantitative disciplines. Therefore, it is interesting to ascertain at what extent the basic concepts may be lost over time. We carried out a survey on students attending third-year courses and over, in the Faculty of Engineering and in the Faculty of Economics, administering a test containing items pertaining to elementary concepts of Mathematics. The results showed that students in the Faculty of Engineering had a better grasp of the mathematical concepts than those in the Faculty of Economics. However, considering the differences between the two Faculties, the gap was actually narrower than what the test results would first lead us to believe. The structure of the model representing the influences of the explanatory variables on the outcome of the test (test score) was similar for both Faculties. In particular, the more predictive factors were high school scores and the number of Mathematics exams already passed at the University. The time elapsed since the last Mathematics exam did not show any particular influence on test scores. However, among the Engineering students, the time elapsed demonstrated a weak concurrent action with other variables, «incorporating» its influence. The correlation between the time elapsed since the last Mathematics exam and the test score was always negative, as expected.


2004 - Measurement and Fuzzy Scales [Relazione in Atti di Convegno]
Lalla, Michele; Facchinetti, Gisella
abstract

Concept measurement presents several difficulties and the tools used to collect qualitative ordinal variables are not always satisfactory. The Likert scale is examined in the context of student evaluation of teaching activity and the measurement approach considers the possibility to apply the fuzzy inference system method to obtain individual values being near the reality and coherent with the prescriptions of the measurement process. The paper presents the results of a survey carried out in the Faculty of Economics at the University of Modena and Reggio Emilia to ascertain the differences between two scales (options): one proposed by the Italian Committee for University System Evaluation (Comitato nazionale per la valutazione del sistema universitario) and another one corresponding to the traditional marks used in the evaluation of student performances in the schools attended before the university (mark scale). The results showed that the latter seemed more coherent with the score (in the decimal scale) assigned to the modalities of the scale.


2004 - Ordinal scales and fuzzy set systems to measure agreement: An application to the evaluation of teaching activity [Articolo su rivista]
Lalla, Michele; Facchinetti, Gisella; Mastroleo, Giovanni
abstract

Student evaluation of university teaching activity is now compulsory in Italy and a research group of the Italian Ministry of Instruction, University, and Research proposed a questionnaire with items based on the four-point Likert scale and a traditional item-by-item analysis for the evaluation of classrooms, work load, course organization, lectures, and teaching aids. Three split-ballot experiments were carried out to test the differences between the four-point and five-point Likert scale. The traditional analysis is compared with the results of the fuzzy system set up to achieve the same purposes. The fuzzy system yielded scores that proved to be generally higher but sometimes also lower than those obtained using the five- or four-point Likert scale. Furthermore, an extension of standard procedures of the fuzzy system is suggested to obtain a fuzzy item-by-item analysis, thereby increasing the possibility of their use in social sciences.


2003 - A Fuzzy Expert System For Evaluating University Teaching Efficiency [Relazione in Atti di Convegno]
Lalla, Michele; Facchinetti, Gisella; Mastroleo, Giovanni
abstract

Student evaluations of University efficiency are compulsory for universities. The Italian Ministry of University and Scientific and Technological Research proposed a questionnaire with items based on the four-point Likert scale and a traditional item-by-item analysis for the evaluation of teaching staff activity. In this study, three split-ballot experiments were carried out to test the differences between the four-point and five-point Likert scale. Furthermore, the traditional analysis was compared with the results of the fuzzy expert system set up to achieve the same purposes. The fuzzy expert system yielded scores that proved to be generally higher but sometimes also lower than those obtained using the five/four-point Likert scale. Copyright © 2001 IFAC


2003 - Il disegno dell’indagine sulle condizioni economiche e sociali delle famiglie nella Provincia di Modena [Working paper]
Lalla, Michele
abstract

This paper describes the survey and sample designs adopted to carry out the income survey in province of Modena. Specifically, it illustrates the determination of the sampling size, the territorial stratification, the selection of sampling units, the calculation of weights, the variance of estimators, post-stratification and calibration, the key-points of nonsampling errors, some indicators of total and partial nonresponses.


2003 - La scala di Likert per la valutazione della didattica [Articolo su rivista]
Lalla, Michele
abstract

The evaluation of teaching staff by students is often carried out with a questionnaire containing items which ask respondents to indicate their agreement with statements using a five-point Likert scale. A mark scale, the characteristics of the scale, the perceptions of students about the intensity of the options of the scale are presented in this paper. The distributions of the numerical values attributable to the Likert scale were derived from the (empirical) data obtained through the analysis of a survey aimed at gathering the opinions (about those values) of the students attending the first year of the Faculty of Economics in Modena. The analysis showed that values on the scale ranging from zero to ten depended on the following: how the question was asked and which terms defined the five categories; the question itself; the kind of course; the intensity level of the Likert scale.


2003 - Organizzazione e valutazione della didattica nella Facoltà di Economia di Modena [Working paper]
Ricci, Gianni; Lalla, Michele; Brugnoli, Carlo; Bordoni, Stefano; Picchio, Antonella; Pilati, Massimo; Russo, Margherita
abstract

Il lavoro esamina gli aspetti essenziali dell'organizzazione dei corsi, del carico didattico, del calendario delle lezioni, della prestazione degli studenti, del processo di apprendimento, del sistema europeo di trasferimento dei crediti, del monitoraggio e della valutazione della didattica a livello di tutta la Facoltà di Economia.NOTA: il testo è curato da G. Ricci e M. Lalla; gli altri autori indicati hanno contribuito a scrivere uno o piú paragrafi.


2003 - Strategia di campionamento per l’indagine sulla valutazione dei corsi di formazione professionale [Articolo su rivista]
Lalla, Michele; Fiorani, G.
abstract

This paper describes the problems to be solved in a survey aimed at evaluating the professional training courses and the sample designs adopted in evaluating the courses of three-year period (2000, 2001, 2002) in Emilia-Romagna. Specifically, it illustrates the determination of the sampling size, the territorial stratification, the selection of sampling units, the calculation of weights, the variance of estimators, the key-points of an income longitudinal survey, some indicators of total and partial nonresponses.


2003 - Una strategia di ripartizione dei fondi di incentivazione dei professori e dei ricercatori universitari [Working paper]
Lalla, Michele
abstract

La Legge n. 370/99 ha introdotto la possibilità di erogare incentivi al personale docente che soddisfi determinati requisiti: un primo tentativo di introdurre una quota variabile di remunerazione in funzione del raggiungimento di fini specifici. Ogni Ateneo dispone di un ammontare da destinare a tale scopo. Il lavoro individua alcune strategie di distribuzione della somma tra le varie Facoltà di un Ateneo, discute i compiti del Nucleo di valutazione interno, e rinvia alle Facoltà la scelta della individuazione dei meritevoli.


2002 - Evaluation of teaching activity through a fuzzy system [Relazione in Atti di Convegno]
Lalla, Michele; Facchinetti, Gisella; Mastroleo, Giovanni
abstract

Student evaluations of teaching staff are compulsory in Italian universities. The Ministry of University and Scientific and Technological Research proposed a questionnaire with items based on the four-point Likert scale and a traditional item-by-item analysis. A fuzzy inferential system is proposed to analyze the data collected through this questionnaire, for items with a four/five-point Likert scale. Fuzzy evaluation was set up with the support of “fuzzyTECH” by INFORM.


2001 - Duration Models and Neural Networks to Analyse Unemployment Spells [Articolo su rivista]
Lalla, Michele; Minerva, Tommaso
abstract

A set of completed spells of unemployment was obtained from the periodic labour force survey with a rotating panel design, carried out by ISTAT in Emilia Romagna, Italy, from the first quarter of 1993 to the first quarter of 1995. The data set was analysed through Cox's proportional hazards model with a Weibull specification of spell length distribution. The empirical distributions of durations showed pronounced spikes which suggests the presence of a considerable telescopic effect. This effect was modelled by an exponential heaping function. Heterogeneity was controlled by adding a suitable set of covariates and unobserved heterogeneity was introduced on the scale parameter of the baseline hazard function. The results were compared with those obtained by a neural network model, but the performance of the latter did not show strong improvement over the former because presumably strong non-linearities and interactions did not underlie the relationships between the spell lengths and the covariates.


2001 - Struttura e cambiamento nelle relazioni tra le imprese metalmeccaniche nella provincia di Modena — II. Distribuzioni degli addetti e pesi per le stime dei parametri [Working paper]
Lalla, Michele
abstract

A database had been set up merging information incorporated in different administrative data set. The purpose was to conduct a survey on the structure and changes in the relationships between enterprises operating in the metal, machinery, and transportation industries. The distributions of the number of employees for each sub-sector of those industries, obtained from the new database, were compared with those obtained from the previous administrative archives. The Kolmogorov-Smirnov test was used to ascertain the differences observed between the various distributions, taking into account the repetition of the application of the test to protect against an error of type I. The new database was used to draw a sample of enterprises, stratified by class interval of employees and by sub-industries. Afterwards, the fundamental elements of the adopted sampling procedure and the problems relative to data collection were described: companies carrying out economic activities differing from the object of interest, dead or untraceable companies, companies subjected to internal or external changes. The strategy to obtain the weights and the precision of the estimates resulting from the data actually surveyed were presented. Moreover, in order to maintain the sample size constant and to incorporate the sampling design into the weights a set of normalized weights was calculated.


2001 - Unemployment duration: An analysis of incomplete, completed, and multiple spells in Emilia-Romagna [Articolo su rivista]
Lalla, Michele; Pattarin, Francesco
abstract

Sets of incomplete and completed spells of unemployment were obtained from the Italian Quarterly Labour Force Survey, carried out by ISTAT in Emilia-Romagna (1993:1-1995:1). The data were analysed through a proportional hazards model with a Weibull specification of the baseline hazard, including both unobserved heterogeneity applied to the scale parameter of the duration distribution, and telescoping effect to account for spikes in the distribution of unemployment spells. They were compared formally also with a non-proportional hazard model based on a log-logistic distribution of duration. The estimation of the parameters was carried out separately on both completed spells and quarterly incomplete spells to ascertain differences and to envisage the potential seasonal effect. The results showed that the shape parameters changed over time. The parameters of each covariate proved to be statistically stable over time and were also equal to the parameters of the completed spells model. Therefore, the analysis of incomplete spells is fairly feasible when an even (closed form) baseline hazard function is suitable for data.


2000 - Inferential fuzzy system for rating instruction [Articolo su rivista]
Lalla, Michele; Facchinetti, Gisella
abstract

The evaluation of teaching staff by students attending the first year of the Faculty of Economics in Modena is carried out with two possible strategies: the easier standard procedure based on the five-point Likert scale and the fuzzy inferential system. The analysis showed that values on the scale of measurement ranging from zero to ten depended on the following: how the question was asked and which terms defined the five categories; the question itself; the kind of course; the intensity level of the Likert scale. To obtain the global evaluation of teaching activity, a fuzzy inferential system was set up with the support of “fuzzyTECH” by INFORM. The resulting crisp values were compared from those obtained by assigning two, four, six, eight, and ten to the five-point Likert-like scale, respectively. The fuzzy inferential system yielded scores greater than the others, on average, by one half.


2000 - Scala di voto e insiemi sfocati per valutare la didattica [Relazione in Atti di Convegno]
Lalla, Michele; Facchinetti, Gisella
abstract

The evaluation of teaching staff by students is often carried out with a questionnaire containing items which ask respondents to indicate their agreement with statements using a five-point Likert scale. To obtain a numeric value on a scale ranging from zero to ten, two possible strategies are presented: the easier traditional procedure and the fuzzy inferential system. The distributions of the numerical values attributable to the Likert scale were derived from the (empirical) data obtained through the analysis of a survey aimed at gathering the opinions (about those values) of the students attending the first year of the Faculty of Economics in Modena. The analysis showed that values on the scale ranging from zero to ten depended on the following: how the question was asked and which terms defined the five categories; the question itself; the kind of course; the intensity level of the Likert scale. A fuzzy inferential system was set up, using the empirical distributions derived form the survey, to obtain the global evaluation of teaching activity. This system was applied to the data of the official survey of the Faculty of Economics. The resulting crisp values were compared from those obtained assigning two, four, six, eight, and ten to the five-point Likert scale, respectively. The fuzzy inferential system yielded scores greater than the others, on the average, by one half.


1999 - Alcuni modelli per l’analisi delle durate complete e incomplete della disoccupazione: il caso Emilia-Romagna [Working paper]
Lalla, Michele; Pattarin, Francesco
abstract

Sets of incomplete and completed spells of unemployment were obtained from the Italian Quarterly Labour Force Survey, carried out by ISTAT in Emilia-Romagna (1993:1--1995:1). The data were analysed through a proportional hazards model with a Weibull specification of the baseline hazard, including both unobserved heterogeneity applied to the scale parameter of the duration distribution, and telescoping effect to account for spikes in the distribution of unemployment spells. They were compared formally also with a non-proportional hazard model based on a log-logistic distribution of duration. The estimation of the parameters was carried out separately on both completed spells and quarterly incomplete spells to ascertain differences and to envisage the potential seasonal effect. The results showed that the shape parameters changed over time. The parameters of each covariate proved to be statistically stable over time and were also equal to the parameters of the completed spells model. Therefore, the analysis of incomplete spells is fairly feasible when an even (closed form) baseline hazard function is suitable for data.


1999 - Analisi della durata della disoccupazione su dati longitudinali e trasversali: il caso Emilia-Romagna [Relazione in Atti di Convegno]
Lalla, Michele; Pattarin, Francesco
abstract

he paper presents the analysis of unemployment duration data gathered by ISTAT in Emilia Romagna, from 1st quarter 1993 to 1st quarter 1995. Exploiting the 2-2-2 rotating scheme of the survey, a set of completed spells was obtained from the nine originally available samples of incomplete ones. Both data sets were modelled by the Weibull distribution. Therefore, referring to the incomplete spells, it was assumed that the unobserved completed spells were Weibull distributed. The empirical distributions of spell durations showed pronounced spikes, which suggest the presence of a considerable telescopic effect. This effect was modelled by an exponential heaping function. Heterogeneity was controlled for by adding a suitable set of covariates. The full model was estimated separately on the completed spells data and for each quarter of the incomplete spells data, to control for potential seasonal effect.


1999 - Career structure and advancement in cardiology in Italy. The Group for the Study of the Italian Status of Cardiologists [Articolo su rivista]
Modena, Maria Grazia; Molinari, R; Lalla, Michele
abstract

Women are less present on the labor market and many studies have demonstrated the existence of gender differences regarding the participation rate and career advancement of women. The processes through which job-, career- and research-related choices are structured within the realm of Italian cardiology is described in this study, emphasizing the effects of productivity, gender and family commitments. In June of 1996, a questionnaire was mailed to all members of the Italian societies of cardiology. It included mainly (pre-coded) set-choice questions concerning individual characteristics, career-related data and information pertaining to teaching, scientific and research activity. Returned questionnaires numbered 1715 (21.4% of the total mailed), with 83% completed by males and 17% by females. For both hospital and academic careers, advancement in rank was influenced by variables denoting productivity, family and individual characteristics. Promotion to the upper ranks of the hierarchy was highly dependent upon time (once the effects of the covariates were eliminated). This is a situation that is typical of the internal labor market or in other words, of an institution in which staff members are ranked on a hierarchical scale according to formal criteria that are "rigid" and institutionalized, partially or totally sheltered from competition. Therefore, once a member has gained access to the first level of the hierarchy, his/her professional career is pre-determined to a certain extent and seniority ends up taking on importance in promotion decisions to an appreciable extent; in this field, the weight of seniority on promotion ranges between 30 and 50%.


1999 - Determinants of career structure and advancement among Italian cardiologists: an example of segregation and discrimination against women? [Articolo su rivista]
Modena, Maria Grazia; Molinari, R.; Lalla, Michele; Gruppo, Scic
abstract

Aims: The aim of this study was to analyse the processes through which job, career and research-related choices are determined in Italian cardiology, focusing on characteristics such as productivity, gender and family. Methods and Results: In June 1996, a questionnaire surveying individual and career-related data was mailed to all members (8000) of the Italian societies of cardiology. Returned questionnaires numbered 1715 (21.4% of the total mailed), 83% were completed by men and 17% by women. For both hospital and academic careers, advancement in rank was influenced by variables denoting productivity, family and individual characteristics. However, men and women showed slightly different patterns. Conclusions: Promotion to the upper ranks of the hierarchy was highly dependent upon time (once the effects of the covariates were eliminated). This situation is typical of the internal labour market, that is, in institutions in which staff members are ranked on a hierarchical scale according to formal criteria that are 'rigid' and institutionalized, partially sheltered from competition. Therefore, once a member has gained access to the bottom of the hierarchy, the professional career is 'pre-determined' and seniority has an appreciable influence on promotion decisions; in this context, women appear to be at a disadvantage.


1999 - La valutazione dell’attività didattica: un confronto tra scale di misura e insiemi sfocati [Working paper]
Lalla, Michele; Facchinetti, Gisella
abstract

The paper reports the initial steps of a research process concerning the evaluation of teaching activity. Specifically it concerns the evaluation of staff by students attending the first year of the Faculty of Economics in Modena is carried out with two possible strategies: the easier standard procedure based on the five-point Likert scale and the fuzzy inferential system. The analysis showed that values on the scale of measurement ranging from zero to ten depended on the following: how the question was asked and which terms defined the five categories; the question itself; the kind of course; the intensity level of the Likert scale. To obtain the global evaluation of teaching activity, a fuzzy inferential system was set up with the support of “fuzzyTECH” by INFORM. The resulting crisp values were compared from those obtained by assigning two, four, six, eight, and ten to the five-point Likert-like scale, respectively. The fuzzy inferential system yielded scores greater than the others, on average, by one half.


1999 - Sampling, Maintenance, and Weighting Schemes for Longitudinal Surveys: a Case Study of the Textile and Clothing Industry [Working paper]
Lalla, Michele
abstract

A longitudinal survey of textile and clothing firms in Emilia-Romagna (Italy) was conducted using a ``replenished'' panel survey to producereliable cross-sectional estimates. The firms (sampling units) were stratified according to size and age, and in all phases, dead and/or emigrated firms were considered as having already left the sample, while new units selected from newborn and immigrant firms, were considered as having already entered the sample. Population dynamics change firm composition over time and the methods of cross-sectional estimation must be adapted to the longitudinal features of the samples. This paper reviews some weighting schemes used in pursuing the aims of repeated sample surveys and presents application trials conducted on real and simulated data.


1999 - Structure and career advancement in cardiology in Italy [Articolo su rivista]
Modena, M. G.; Molinari, R.; Lalla, M.
abstract

Women are less present on the labor market and many studies have demonstrated the existence of gender differences regarding participation rate and career advancement of women. The process through which job-, career- and research-related choices are structured within the realm of Italian cardiology, is described in this study emphasizing the effects of productivity, gender and family commitments. In June 1996, a questionnaire was mailed to all members of the Italian societies of cardiology. It included mainly (pre-coded) set-choice questions concerning individual characteristics, career-related data, and information pertaining to teaching, scientific and research activity. Returned questionnaires numbered 1715 (21.4% of the total mailed), 83% were completed by males and 17% by females. For both hospital and academic careers, advancement in rank was influenced by variables denoting productivity, family and individual characteristics. Promotion to the upper ranks of the hierarchy was highly dependent upon time (once the effects of the covariates were eliminated). This is a situation that is typical of the internal labor market, that is, of an institution in which staff members are ranked on a hierarchical scale according to formal criteria that are "rigid" and institutionalized, partially and totally sheltered from competition. Therefore, once a member has gained access to the first level of the hierarchy, his/her professional career is to a certain extent pre-determined and the seniority ends up taking on importance in promotion decisions to an appreciable extent; in this field, the weight of seniority on promotion ranges between 30 and 50%.


1999 - Struttura e avanzamento di carriera in cardiologia in Italia [Articolo su rivista]
Modena, Maria Grazia; Molinari, R.; Lalla, Michele; Gruppo, Scic
abstract

Women are less present in the labour market and many studies have demonstrated the existence of gender differences regarding participation rate and career advancement of women. The process through wich job-, career- and research-related choices are structured within the realm of Italian cardiology, is described in this study emphasizing the effects of productivity, gender and family commitments. In June 1996, a questionnaire was mailed to all members (8000) of the Italian society of cardiology. It included mainly (pre-coded) set-choice concerning individual characteristics, career-related data, and information pertaining to teaching, scientific and research activity. Returned questionnaires numbered 1715 (21.4% of the total mailed), 83% were completed by men and 17% by women. For both hospital and academic careers, advancement in rank was influenced by variables denoting productivity, family and individual characteristics. However, men and women showed slightly different patterns. Promotion to upper ranks of hierarchy was highly dependent upon time (once the effects of the covariates were eliminated). This situation is typical of the internal labour market, that is, in institutions in which staff members are ranked on a hierarchical scale according to formal criteria that are ‘rigid’ and institutionalized, partially sheltered from competition. Therefore, once member has gained access to the bottom of the hierarchy, the professional career is ‘pre-determined’ and seniority has an appreciable influence on promotion decisions; in this context, women appear to be at a disadvantage.


1998 - La progressione delle carriere: i percorsi in cardiologia [Working paper]
Lalla, Michele; Molinari, Roberto; Modena, Maria Grazia
abstract

Il lavoro riporta i risultati di una indagine condotta per raccogliere i dati relativi ai percorsi delle carriere in cardiologia e ai fattori che possono influenzarle, come la produttività e il genere. Nel giugno del 1996 si è condotta una indagine tramite questionario postale inviato agli aderenti della Società italiana di cardiologia: il 21% dei questionari inviati è stato compilato e, tra questi, l’83% erano uomini e il 17% erano donne. Le promozioni dipendono dal tempo di permanenza nello stato, dopo che si sono eliminati gli effetti delle covariate. Le donne sono svantaggiate.


1997 - Alcuni modelli per l’analisi univariata delle durate della disoccupazione: il caso dell’Emilia-Romagna [Altro]
Lalla, Michele; Pattarin, Francesco
abstract

Il lavoro presenta le prime elaborazioni di un gruppo di indagini o rilevazioni trimestrali sulle forze di lavoro condotte dall’Istat nella regione Emilia-Romagna (1993:1--1995:1). In particolare si sono considerati i periodi di disoccupazione, analizzate con i modelli di durata, utilizzando il modello dei rischi proporzionali e la specificazione della distribuzione di Weibull per le durate e il rischio di base. L’eterogeneità non osservabile è stata applicata al parametro di scala della distribuzione delle durate. La stima dei parametri è stata condotta sia sulle durate complete sia sulle durate incomplete.


1996 - Lezioni di probabilità e inferenza statistica [Working paper]
Lane, David Avra; Poli, Irene; Lalla, Michele; Roverato, Alberto
abstract

Il lavoro contiene il testo delle lezioni del corso di statistica (pp. 1-295). (I) Probabilità. (I) Probabilità condizionale. (III) Numeri aleatori discreti. (IV) Caratterizzazioni dei numeri aleatori discreti. (V) Numeri aleatori continui e loro caratterizzazione. (VI) Il teorema del limite centrale (VII) Il significato di probabilità. (VIII) Teoria bayesiana delle decisioni (IX) Introduzione all’inferenza statistica. (X) Inferenza bayesiana.


1996 - Lezioni di probabilità e inferenza statistica – Esercizi svolti [Working paper]
Lane, David Avra; Poli, Irene; Lalla, Michele; Roverato, Alberto
abstract

Il lavoro contiene i testi degli esercizi svolti e proposti nel corso di statistica (pp. 1-300). (I) Probabilità. (I) Probabilità condizionale. (III) Numeri aleatori discreti. (IV) Caratterizzazioni dei numeri aleatori discreti. (V) Numeri aleatori continui e loro caratterizzazione. (VI) Il teorema del limite centrale (VII) Il significato di probabilità. (VIII) Teoria bayesiana delle decisioni (IX) Introduzione all’inferenza statistica. (X) Inferenza bayesiana.


1996 - The influence of depression on memory and metamemory in the elderly [Articolo su rivista]
CIPOLLI, Carlo; NERI, Mirco; DE VREESE, Luc Pieter; PINELLI, Marina; RUBICHI, Sandro; LALLA, Michele
abstract

This study aimed to assess the relationships among depression level, memory and metamemory scores on a large sample of elderly subjects (139 men and 147 women). Preliminary examination showed that none of the sampled subjects had intellectual impairment (as assessed by means of the Mini-Mental State Examination) or neuropsychiatric symptoms. Each subject was administered the Randt Memory Test (RMT), the Sehulster Memory Scale (SMS) and the Geriatric Depression Scale (GDS). A Multivariate Analysis of Covariance revealed a negative influence of depression on the two RMT measures (Acquisition-Recall: AR; Delayed Memory: DM) and on the three SMS measures (Set1: self-comparison; Set2: memory complaints; Set3: peer comparison), and of age on AR and DM, and Set1 and Set2. A Multivariate Regression Analysis showed that DM scores were positively correlated with Set2 in men and women, and with Set1 in women and Set3 in men, whereas AR scores related to Set2 and Set3 in men and Set1 in women. In addition, depression influenced negatively Set1, Set2 and AR scores in both men and women and DM scores only in men. On the whole, the results suggest that depression, memory and metamemory are rather closely related in non-severely depressed older individuals, albeit with slightly different patterns in men and women, and that some areas of metamemory are congruent with objective functioning regardless of the level of depressive symptoms.


1996 - Un’indagine longitudinale nel settore tessile e abbigliamento: alcuni aspetti del piano di campionamento [Relazione in Atti di Convegno]
Lalla, Michele
abstract

A longitudinal survey of textile and clothing firms in Emilia-Romagna (Italy) was conducted using a ``replenished'' panel survey to produce reliable cross-sectional estimates. The firms (sampling units) were stratified according to size and age, and in all phases, dead and/or emigrated firms were considered as having already left the sample, while new units selected from newborn and immigrant firms, were considered as having already entered the sample. Population dynamics change firm composition over time and the methods of cross-sectional estimation must be adapted to the longitudinal features of the samples.


1995 - L’indagine sui consumi: alcune verifiche su proposte di campionamento alternative [Working paper]
D., Cocchi; Lalla, Michele
abstract

The paper presents some changes on the strategies adopted by Istat in the data collection on consume. Specifically, it examines the changes concerning the registration period of consume, the stratification of the primary sampling units (PSU), the rotation schemes for the PSUs, the sampling size. Moreover, it considers the sampling estimators and some simulations about the inclusion order of PSUs.


1995 - Modelling Incomplete Spells of Unemployment and Employment [Articolo su rivista]
Lalla, Michele
abstract

The procedure used to analyse a data set which includes only censored or incomplete spells is examined in this paper. First of all, the distributions of the incomplete spells of employment are analysed without explanatory variables (such as age, sex, etc.), assuming that the unobserved completed spells have a Weibull distribution. The relationships between the mean of the incomplete spells and the mean of the completed spells are reported for first-job seekers, unemployed, employed, and self-employed workers. Given that the unobserved completed spells are Weibull-distributed, the unobserved heterogeneity is introduced on the scale parameter of the Weibull. The heterogeneity, considered as a variable, is analysed for a binomial or Weibull distribution. As the beginning of a spell a retrospective datum, the recall errors are modelled including the heaping effect. Using some proportional hazards models, the methodology to study the influences of explanatory variables on spell distributions is then described, once again including both the heterogeneity and the heaping effect. On this basis, the lengths of on-going spells of unemployment for first-job seekers and unemployed workers are modelled, as well as the current job tenures of employed and self-employed workers.


1994 - Appendice metodologica. L’indagine panel nella seconda occasione: note sul campione e sulle stime [Altro]
Lalla, Michele
abstract

The paper reports the description of second wave of a longitudinal survey of textile and clothing firms in Emilia-Romagna (Italy), which was conducted using a “replenished” panel survey to produce reliable cross-sectional estimates. The firms (sampling units) were stratified according to size and age, and in all phases, dead and/or emigrated firms were considered as having already left the sample, while new units selected from newborn and immigrant firms, were considered as having already entered the sample. Population dynamics change firm composition over time and the methods of cross-sectional estimation must be adapted to the longitudinal features of the samples.


1994 - Caratteristiche generali delle banche dati [Altro]
Lalla, Michele
abstract

Il lavoro descrive le caratteristiche generali e le funzioni delle banche dati disponibili in quegli anni: produttori e distributori, linguaggio di interrogazione, modalità di accesso, i costi delle interrogazioni, le reti per la ricerca, i servizi offerti dal distributore, i gateway, il mercato dell’informazione, le basi di dati su CD-ROM, i problemi e le difficoltà.


1993 - Modelling incomplete spells of unemployment and employment [Altro]
Lalla, Michele
abstract

The paper presented the scheme to analyse the unemployment duration data: completed and interrupted spells. Both data sets were modelled by the Weibull distribution. Therefore, referring to the incomplete spells, it was assumed that the unobserved completed spells were Weibull distributed. Heterogeneity was controlled for by varying the location parameter of the Weibull distribution.


1993 - Sample Redesign of the Italian Consumer Expenditure Survey [Altro]
Cocchi, D.; Lalla, Michele
abstract

The paper presented the design of the current Italian consumer expenditure survey and a sample redesign for the same survey with a possible rotation scheme of the primary sampling units (PSU)


1992 - Appendice metodologica. Finalità e costruzione di un campionamento nel tempo: l’indagine panel [Altro]
Lalla, Michele
abstract

The paper reports the description of first wave of a longitudinal survey of textile and clothing firms in Emilia-Romagna (Italy), which was projected to be conducted using a “replenished” panel survey to produce reliable cross-sectional estimates. The firms (sampling units) were stratified according to size and age, and in all phases, dead and/or emigrated firms were considered as having already left the sample, while new units selected from newborn and immigrant firms, were considered as having already entered the sample. Population dynamics change firm composition over time and the methods of cross-sectional estimation must be adapted to the longitudinal features of the samples.


1992 - L’indagine panel con rotazione su ingressi e uscite: alcune simulazioni con i dati INPS [Relazione in Atti di Convegno]
Lalla, Michele
abstract

The sampling procedure presented in this paper was used to collect panel data and it is based on the following rotation design. The panel life of the sample elements corresponds to their natural life. At different points of time, the deaths and outmigrants leave the panel; new elements are added, selecting them from the births and immigrants. Therefore, the rotation depends on “random” natural events, such as births and deaths, immigration and outmigration. The resulting panel should incorporate the target population dynamics and increase its representativeness. The unmatched and matched portions of successive samples provide estimates of the births, y(bt), and the continuing population, y(mt). In the matched portion, the doublesampling regression estimate is generally used, y’(mt). The best combined estimate of Y(t) is found by weighting y’(bt) and y’(mt) inversely as their variances (Cochran, 1977; Patterson, 1950). If y(bt) is systematically lower than y’(mt), then the doublesampling regression estimate does not work well. Alternative weights are the proportions of the births and the total units of population at time t. The matched portion may be estimated by a simple autoreressive model. This sampling design was applied to the administrative data of the National Institute of Social Security (INPS: Istituto Nazionale della Previdenza Sociale) for the years from 1982 to 1988, relative to the Province of Modena. The estimates of the population mean, total, and unit seemed to be satisfactory, as did their variances.


1992 - Proposte alternative alla rotazione completa nell’indagine sui consumi delle famiglie [Working paper]
Lalla, Michele
abstract

The paper examines some longitudinal designs and the corresponding potentialities for the analysis of data collected on consume. Specifically, it discusses some aspects of the sampling design: the registration period of consume, the stratification of the primary sampling units (PSU), the rotating panel, and the dynamic of the target population. Moreover, it considers the models for data analysis to obtain estimation for the entity of phenomena, multivariate analysis, and duration analysis.


1990 - La scala S.V.E.B.A. per la misurazione dello stato emotivo-affettivo dell’anziano [Relazione in Atti di Convegno]
Neri, Mirco; C., Cortelloni; G., Giorgi; A., Spanò; Cipolli, Carlo; Lalla, Michele
abstract

The paper presents the first step analysis of data collected to build up a psychometric tool, consisting of 15 “yes/no” questions and termed “Scala di Valutazione dell’Emotività e del Benessere dell’Anziano” (SVEBA) (Evaluation Scale of Affectivity and Well-Being in the Elderly), aimed at a rapid clinical screening of affective disorders. A validation study of the scale matched the SVEBA score and both the interview evaluation and the Symptoms Rating Test score of R. Kellner and B. F. Sheffield (SRT-Italian validated form). The sample was constituted by 321 volunteers. The results confirmed a high concomitant validity with respect to both SRT and clinical evaluation. High correlations were observed between the two global measurements and for subgroups obtained by gender, residence area, age classes.


1990 - Modelling employment spells from Emilian labour market [Working paper]
Lalla, Michele
abstract

The analysis of employment spells obtained from a Cross Population Survey (CPS) should take into account the phenomenon of length-bias because CPS-type data are generally right-censored. The paper presents the procedure to analyse a data set which includes only censored or incomplete spells. First of all, the distribution of the incomplete spells of employment are analysed without explanatory variables (such as age, sex, etc.), assuming that the unobserved completed spells have a Weibull, a logistic, or a Gompertz distribution, and the best assumption is adopted (the Weibull). Using the constant and the time-dependent proportional hazards models, the methodology to study the effects of explanatory variables on spell distribution is then described for both incomplete spells and incomplete spells considered as completed ones. These methods are then applied to the lengths of ongoing spells of employment for employed and self-employed workers.


1990 - Relazioni fra livelli di depressione e misure soggettive ed obiettive di memoria nell’anziano [Articolo su rivista]
Cipolli, Carlo; Lalla, Michele; E., Andermarcher; Pinelli, Marina; Neri, Mirco
abstract

The influence of depression on the functioning of long-term memory in the elderly is not completely known. The study aimed to assess the relationship between the scores of subjective assessment (metamemory) and those of performance testing for memory, on the one hand, and the level of depression , on the other. 180 elderly subjects (102 women and 78 men; mean age 67.5 yr) were selected for this study. They were all without intellectual impairment (as assessed through MMS) and neuropsychiatric symptoms. The Randt Memory Test (RMT) for performance testing, the Sehulster Memory Scale (SMS) for the subjective assessment, and the Geriatric Depression Scale (GDS) were administered to each subject. A multiple regression analysis showed that the level of depression was inversely correlated with both the measures (Acquisition-Recall: AR, Delayed Memory: DM) of RMT, and that, with the same level of depression, men’ scores for AR and DM were slightly lower than those of women. The age appeared inversely correlated only with AR scores. The scores of the second (memory complaints) of the three sets of SMS were positively correlated with those of AR and MD indices. Overall the results suggest: (a) that the relationships between not clinical relevant levels of depression and different indices of memory functioning are substantial in the elderly, although not fully homogeneous in men and women, and (b) that the scores in some areas of metamemory parallelize, independently on the level of depression, the performance outcomes of memory functioning.


1990 - S.V.E.B.A. una scala per la valutazione del benessere emotivo dell’anziano [Articolo su rivista]
Neri, Mirco; C., Cortelloni; A., Spanò; Cipolli, Carlo; Lalla, Michele
abstract

The “Scala di Valutazione dell’Emotività e del Benessere dell’Anziano” (SVEBA) (Evaluation Scale of Affectivity and Well-Being in the Elderly) is a psychometric tool consisting of 15 “yes/no” questions, devised for the rapid clinical screening of affective disorders. A validation study of the scale matched the SVEBA score and both the interview evaluation and the Symptoms Rating Test score (SRT-Italian validated form). The subjects (321 volunteers) were distributed according to essential socio-demographic characteristics of the Italian population. The results confirmed a high concomitant validity with respect to both SRT and clinical evaluation, although with respect to the latter it revealed less specificity. In two subsequent trials with out-patients and long-term hospitalized patients, the SVEBA scale showed a high degree of empirical validity and a satisfactory sensitivity also in the case of slight-mild cognitive deficit. The presence of medical illness appeared to be unrelated to the affective distress quantified by the SVEBA scale.


1990 - Self-rating and objective memory testing of normal and depressed elderly [Articolo su rivista]
Cipolli, Carlo; Neri, Mirco; E., Andermarcher; Pinelli, Marina; Lalla, Michele
abstract

This study aimed to assess the relationships between the scores of subjective assessment (metamemory) and those of performance testing for memory, on the one hand, and the level of depression, on the other. A hundred and eighty elderly subjects (102 women and 78 men; mean age 67.5 years) were selected for the study. They showed neither intellectual impairments (as assessed through Mini Mental State test: MMS) nor neuropsychiatric symptoms. Each subject was administered the Randt Memory Test (RMT) for performance testing, he Sehulster Memory Scale (SMS) for the subjective assessment, and the Geriatric Depression Scale (GDS). A MULTCOVA analysis showed that both age and the depression level are negatively correlated with the measures (Acquisition-Recall: AR; Delayed Memory: DM) of the RMT. The scores of the second (memory complaints) of the three sets of SMS were positively correlated with those of AR and DM indices. A Multivariate Regression Analysis showed that, in males, the age and the depression level were significant regressors for both AR and MD scores, while in females only the depression level was a significant regressor for DM. Overall the results suggest: (a) that the relationships between the depression level and memory functioning are close, although not fully homogeneous in men and women; and (b) that the scores in some areas of metamemory parallelize, independently on the level of depression, the performance outcomes of memory functioning.


1990 - Stima dei parametri della funzione di ripartizione dei periodi trascorsi: il caso dell’anzianità aziendale [Articolo su rivista]
LALLA, Michele
abstract

The duration data sets used to study employment or unemployment often come from samples of individuals at a point in time (Cross Population Survey, CPS) and they contains the lengths of ongoing spells of employment or unemployment for sample subjects who are currently employed or unemployed. The observations are right-censored and termed spells in progress or incomplete spells. The analysis of the raw data involves a length-biased estimate of spell durations. In this paper, we examine the procedure to analyze a data set which includes only censored or incomplete spells when the full lengths of spells, conditioned on their being in progress at the time of survey, are Weibull distributed. Particularly, the methodology of estimation of the parameters is described for both the distribution function of spell durations and the proportional hazard model which include a set of explanatory variables (personal and job characteristics, local labor demand). Then, the methods are applied to the lengths of ongoing spells of employment for both employed workers and self-employed workers.


1989 - Valutazione dei fattori di rischio di atopia nel 1° anno di vita. Ricerca policentrica [Articolo su rivista]
GENOVA, Rosalia; M., Masi; M., Calacoci; R., Chierici; E., Agazzani; A., Guerra; G. P., Salvioli; F., Specchia; P., Dalla Casa; L., Osti; BALLI, Fiorella; G., Frigeri; C., Zambonati; F., Ceroni; M., De Palma; LALLA, Michele
abstract

The authors studied 406 patients newborn babies during the 1st year of life in order to verify the correlation between atopy risk factors and the appearance of early symptoms, particularly gastroenteric (GE). The results obtained did not demonstrate a significant difference concerning the blood cord IgE level and subsequent appearance of food allergy symptoms, whereas positive familiarity showed a better correlation. No significant difference was observed between breast – or formula – fed infants, or between those weaned before or after the 5th month of life. The comparison of dietary regimen adopted during the 1st quarter in the asymptomatic and atopic children respectively, demonstrated that the presence of the predisposing factors influences the appearance of GE symptoms much more than the diet in itself. An allergologic study, randomly performed by Prick-test in 156 cases and by RAST in 200 cases, showed a prevalent, positive response with RAST technique in symptomatic children.


1988 - Funzioni di distribuzione dei tempi di disoccupazione: analisi di periodi osservati e “simulati” [Working paper]
Lalla, Michele
abstract

The paper presents a review of the models and the procedures to analyze data sets including only completed spells, or censored and completed spells, or only censored or incomplete spells of unemployment considering the case without covariates (such as age, sex, etc.). The distributions of the incomplete spells of employment were analysed considering one at a time the popular ones: beta, gamma, logistic, lognormal, normal, Pareto, extreme values, and Weibull. Moreover, sets of simulated spells were analysed to verify the values of the exit rate, i.e., the spells generated from a model of queue and simulated through a representative scheme of the flows in the labour market.


1988 - Procedure per la validazione di un test: la scala S.V.E.B.A. [Articolo su rivista]
Lalla, Michele
abstract

This paper deals with the methodology and the statistical procedures for the analysis of the data used to develop and to validate a short scale for the assessment of the emotionality and the well-being in elderly patients; this scale is called SVEBA. The scale of Savage and Britton (1967) and the scale of Pfeiffer (1979) were administered to 519 subjects. A mixture of statistical techniques (discriminant, factor, and correlation analysis) was used to build up a different scale from the foregoing ones; a set of 15 items was selected. The resulting set was administered to another group of 73 subjects to verify its performance and to adapt the items for the local situation. A group of psychologists classified them in normal, borderline, or pathological patients. At this stage, the items were slightly adapted in some cases to a form more suitable for oral administration and two items were replaced with two new ones. The resulting scale was administered to a third group of 321 subjects, who were classified by psychologists as in the previous case. The validation was achieved comparing the outcomes of the SVEBA with psychological classification.


1986 - Appendice statistica. La metodologia del campionamento [Altro]
Lalla, Michele
abstract

This appendix deals with the sampling procedures applied to the study of the construction firms in Italy. Six independent samples were selected in six Italian Towns, constituting a reasoning sample of the geography of the Sector: Rome was investigated in a pilot survey. A univariate stratification procedure was applied to the variable “number of hired workers” estimated for each firm. For each stratum, weights were calculated as means of monthly observations. The results of this approach were compared with those obtained from a dynamic model of the firms’ population. The relative efficiency of this procedure was estimated with respect to the traditional sampling procedure based on a static specification.


1986 - Terapia della insufficienza cerebro-vascolare con calcio antagonisti. Criteri di valutazione [Articolo su rivista]
Neri, Mirco; Lalla, Michele; Cortelloni, C.
abstract

Si è selezionato un campione nell’àmbito delle cerebropatie vascolari croniche e ci si è riferiti a una classe di farmaci, i Ca++ antagonisti, dotata di suggestive e differenziate azioni farmacologiche, per curare i disturbi della macro- e micro-circolazione, oltre ai disturbi del metabolismo energetico e neurotrasmettitoriale. I test e il modello utilizzati hanno mostrato che oltre al trattamento esistevano altre variabili che da sole o per interazioni con queste costituivano significative fonti di modulazione del punteggio.


1985 - Psicometria dell’affettività dell’anziano [Articolo su rivista]
Neri, Mirco; Gozzi, Elisa; Mazzi, Fausto; C., Cortelloni; Lalla, Michele; V., Boccaletti
abstract

Rating scales in the assessment of affective disorders of the aged are widely used, but Italian versions of these instruments are lacking. In literature two 15-items evaluation schedules, both derived from MMPI and validated in aged people, may be found. A study was designed to assess whether their Italian versions behave in the same manner in classifying the sample (590 aged subjects, males and females) and whether concomitant variables (age, sex, physical fitness, etc.) may be source of variability. Final results showed that sex only was a significant source of variability for both scales, besides the sample was classified into two main groups (normal and psychopathological) without significant difference. A discriminant analysis on the scores showed that in both scales six items only had the main right classification power.


1985 - Rapporto tra titolo di studio e occupazione nel Comune di Modena [Altro]
Lalla, Michele
abstract

Il saggio descrive i risultati di una indagine condotta nel corso di Trattamento delle informazioni nelle ricerche sociali, Scuola di Informatica per Analisti di Sistemi e Procedure, Facoltà di Scienze Matematiche Fisiche e Naturali dell’Università di Modena. Lo scopo era prevalentemente didattico, ma il corale coinvolgimento degli studenti e l’entusiasmo ha dilatato gli obiettivi inziali. Anche l’esposizione segue il processo di ricerca nelle sue ordinarie quattro fasi: l’impostazione del lavoro, dove si fissano gli obiettivi e le definizioni dei termini e delle ipotesi; la raccolta dei dati, con la descrizione del campionamento e del questionario; l’elaborazione dei dati; e infine la presentazione dei risultati. In particolare si illustrano i motivi di interruzione degli studi, i canali di ricerca del lavoro, il rapporto tra titolo di studio e il lavoro svolto, il settore di occupazione, l’utilità degli studi effettuati, la professionalità dopo il lavoro, la soddisfazione e l’atteggiamento sul lavoro, l’aggiornamento professionale e l’atteggiamento verso lo studio.


1984 - Follow-up study of 482 cases with convulsive disorders in the first year of life [Articolo su rivista]
Cavazzuti, Giovanni Battista; Ferrari, Paola; Lalla, Michele
abstract

A total of 482 patients who had one or more seizures in the first year of life were followed for at least five years (most for more than 10 years). The patients were divided into four groups: febrile convulsions, infantile spasms, status epilecticus and ‘other’. Of those with febrile convulsions, 62 percent developed normally, compared with 14 percent in the group with infantile spasms, 15 percent with status epilecticus, and 24 percent in the ‘other’ group. Findings on the recurrent seizures, epilepsy and mental retardation and/or neurological abnormalities are also reported. Epilepsy developed equally frequently among those with partial and with generalized seizures, but the former more frequently became mentally retarded. The effects of severity of seizures and other factors are discussed. In general, confirmed the grave prognosis after seizures during the first year of life, and not only for West syndrome and status epilecticus. The outcome was more favourable when the seizures were cryptogenic or febrile, isolated, with onset in the second six months, generalised, and when the EEG was normal between seizures.


1984 - Indagine sui canali formativi del personale EDP [Altro]
Lalla, Michele
abstract

Il lavoro descrive i risultati dell’indagine promossa dal comitato che progettava un corso universitario di informatica. L’obiettivo consisteva nell’accertamento della diffusione dell’uso dell’informatica nelle aziende e della preparazione del personale adibito al processo dei dati, EDP (Electronic Data Processing). Si riportano la metodologia di campionamento, le caratteristiche comuni a tutte le imprese e del personale EDP, la dinamica e la preparazione del personale EDP; infine, le caratteristiche delle imprese contattate per telefono.


1984 - L’ipertensione arteriosa in età pediatrica. Studio di una popolazione scolastica [Articolo su rivista]
GENOVA, Rosalia; T., Cappellini; A., Guerra; F., Amore; LALLA, Michele
abstract

Most authors fix the upper limits of normal blood pressure at 90th percentile according to age. Nevertheless in their investigation different instruments were used and the often did not relate in detail the position of the subject during the measurement. Other factors, influencing blood pressure values, have been often left out: relation with meals, room temperature, pain, drugs, stress, and so on. The prevalence of hypertension in pediatric age in literature is 0.6-12.4% with several intermediate values. The first very important research concerning the hypertension in pediatric age was carried out by Londe et alii, conducted among 1593 children (785 males and 798 females); they estimated mean values and percentiles according to age and sex. In the present study the authors saw 346 children (161 females and 185 males), 11-15 years old, observed at school, in a comfortable room. Pressure measurement was done twice in the same morning with half an hour interval. Systolic pressure, 4th and 5th Korotkoff tones, was noticed. 11% of the children had systolic pressure values under 50th percentile, 35.3% between 50th and 90th percentile, and 43.1% had values equal to or greater than 90th percentile at the first measurement. The third group went down to 30.6% (106 cases) at the control (after an half an hour). This reduction shows the importance of the emotional factors in the P.A. variations. The 106 children who had systolic and/or diastolic values equal to or greater than 90th percentile were controlled again after a week. 92 children maintained the same values. They were called for the third sitting 1-6 months later. Only 45 subjects agreed our invitation and it was possible to point out that high blood pressure values persisted in 31 children (that is 8.9% of all examined cases). Following correlations were observed: (a) body weight-blood pressure values (either systolic or diastolic ones) and so cutaneous plica-pressure values (p<0.01); (b) moreover, 50% of the 31 hypertensive children had hypertensive parents; (c) the most frequent subjective symptom (13 cases) was cephalalgia. None of the studied school children showed either clinic or biochemical abnormal data, so that it was possible to define their hypertension as “essential”.


1983 - Estremi di classe e dimensione campionaria da una popolazione variabile nel tempo [Articolo su rivista]
Lalla, Michele
abstract

In this paper we present the empirical results of a sampling survey of construction firms of the town of Ravenna. The univariate stratification procedure was used as sampling technique and the number of hired workers was taken as stratification variable. The procedure developed by Dalenius and Hodges (1959) for the division of firms’ population into strata and the optimal allocation for the choices of the relative sample sizes were applied to all firms with the stratification variable different from zero every months: from January 1979 to September 1980. The series of the boundaries of the strata and those of the relative sampling sizes for the same period were obtained and the means of the series were taken to construct the sampling. The results of the inquiry, the weights, and the relative efficiency with the respect to the traditional sampling are reported.


1983 - Funzione di risposta e fertilità residua dei prati stabili nel piacentino [Articolo su rivista]
P., Paris; Q., Paris; Lalla, Michele; C., Gavazzi
abstract

A pluriannual experiment was conducted at Verano (PC) to measure the yield response to N and P of irrigated grassland. A split-plot experimental design with five N treatments (100, 150, 200, 400, and 800 kg/ha N per year) and three P sub-treatments (0, 100, and 200 kg/ha P2O5 per year) was executed between 1975 and 1981, with levels of hay (dry matter) production far above those achieved with traditional applications. A Liebig response function, embodying the famous law of minimum, was chosen to represent the response relation between hay production and fertilizers. The N response is satisfactorily represented by a linear and plateau (LRP) function. The P response was estimated by means of a Mitscherlich exponential function and a fertility carryover equation which relates the quantity of available P in the soil at time t to the same quantity at t0 the accumulated additions of P and the total amounts removed by the crop. Such a Liebig response function seems to fit the data very well. The optimal P fertilizer application is computed by taking into account the price ratio, as usual, but also the amount of available P in the soil. The optimal amount of N, on the contrary, is independent of the price ratios and corresponds to the knot in the linear spline.


1982 - Correlazione tra IGE e IGA plasmatiche nella nefrosi infantile e nella sindrome nefrosica [Articolo su rivista]
A., Guerra; T., Cappellini; C., Chiossi; G., Bonvini; LALLA, Michele; GENOVA, Rosalia
abstract

A study on IgE - IgA plasmatic level has been carried out in the acute phase and in remission of minimal changes nephrosis (MCN) and in glomerulonephritis with nephrotic syndrome (NS). The results obtained are the following: (1) Mean values of Ig classes were impaired in comparison with the normal values of children of the same age, bon MCN and NS. (2) IgE were increased, particularly in children over 6 years in the MCN acute phase; the values decreased within normal after the remission was achieved. (3) IgA, on the contrary, were decreased in the subjects over 6 years, in the MCN acute phase. (4) No significant correlation was found between the two Ig classes. (5) The modification of the Ig plasmatic level during the remission, after corticosteroid therapy was characterized by IgE reduction; IgA were only slightly, but not significantly, decreased in the same phase.


1982 - La microematuria asintomatica [Articolo su rivista]
T., Cappellini; A., Guerra; F., Canonaco; GENOVA, Rosalia; LALLA, Michele
abstract

Microscopic haematuria is a urinary finding more and more frequently observed in routine analysis in childhood. The diagnostic problems, most of which unresolved, are yet the principal question concerning in. We have studied 123 patients during five years from 1975 to 1980, and followed them for 1-8 years (mean 4 years). Oue experience allowed us to consider “normal” or without remarkable pathologic significance a urinary findings less than or equal to 5,000 RBC/m’ at the Addis count. Such findings was pointed out in 55 cases (44%); 27 patients (22%) had 5-10,000 RBC/m’, 34 patients (27.6%) presented 10-50,000 RBC/m’, and 7 cases (5.7%) had more than 50,000 RBC/m’. The familiar background, the clinical, biological, and immunological data, the roentgenographic investigations and the renal biopsy carried out in 4 group of patients, led us to the following conclusions: (1) 26% of the 123 cases had an “unexplained” microscopic haematuria with complete lack of anamnestic data, symptomatology and with normal biological findings. (2) In 65.8% of the cases it was possible to discover frequent upper respiratory tract infections (and allergy in 5.6% of them). (3)In 26% of the patients we discovered a previous or actual genitor-urinary (10.5% and 15.5% respectively) infection: 9.4% of 96 urographies demonstrated a variable degree of nephro-urological abnormalities. (4) 23 children (18.7%) was selected for renal biopsy, primarily by the hypocomplementemia and positive anti-DNA ab. Test, and secondly by elevated degree of microematuria. The histological and immunohistochemical studies demonstrated the presence of mesangial proliferation glomerulonephritis with IgC-IgA-C3 deposits in 7 cases (30% of the cases biopsied and 5.6% of the total), 69.6% of the cases had only minimal changes with negative immunofluorescence. (5) A mean follow-up of 4 years in two groups of patients (<and> 6 years of age) has demonstrated that microscopic haematuria remains unchanged in 18-19% of both groups. A more marked improvement or normalization has been documented in the children more than 6 years aged (p<0.001) while a worsening has been observed in the children less than 6 years aged (p<0.005), with a difference statistically significant between the two groups considered.


1982 - Rilievi statistici nell’attività ambulatoriale in neuropsichiatria infantile [Articolo su rivista]
Curci, Paolo; Ruggerini, Ciro; E., Ferrari; Lalla, Michele; M. R., Tassi; V., Fugazza
abstract

The authors have carried out a statistical investigation on the activities of the out-patients’ Department of Child Psychiatry and have focused their attention especially on the characteristics of the service and on its functioning. It is manifested that the average of patients are included between school age and pre-adolescence, that they come from low-middle class and that the kind of requests we receive involve all sectors of neurology and child psychiatry. It has also been evidenced a certain flexibility and adaptability in the operative suggestions, even if there was a basic limiting attitude as far as the most medicalizing and family involving aspects were concerned.


1982 - Un problema di campionamento stratificato in una popolazione variabile nel tempo [Articolo su rivista]
LALLA, Michele
abstract

In this paper we present the empirical results of a sampling study of construction firms in the city of Rome over a period of eighteen months. A univariate stratification procedure was applied to the variable “number of hired workers” estimated for each firm. For each stratum, weights were calculated as means of monthly observations. The results of this approach were compared with those obtained from a dynamic model of the firms’ population. The relative efficiency of this procedure was estimated with respect to the traditional sampling procedure based on a static specification.


1980 - Valutazione dei fattori che influenzano l’attività reninica plasmatica e l’aldosteronemia nella prima infanzia [Articolo su rivista]
GENOVA, Rosalia; BALLI, Fiorella; ZANIOL, Paolo; LALLA, Michele
abstract

Renin-angiotesin-aldosterone system (RAA) was investigated in 36 children 20 days to 23 months old, with different dietary electrolyte intakes. Plasma rennin activity (PRA) and Plasma aldosterone level (P-aldo) were related to sodium and potassium intake (NaD, KD) and to sodium and potassium excretion (NaU, KU) expressed in mEq/kg/day and to the age. The children, divided in 3 groups (A, B, C), received respectively: NaD (0.93 +/- 0.03 mEq in the group A, 2.14 +/- 0.10 mEq in the group B, 2.32 +/- 0.23 mEq in the group C) and KD (1.77 +/- 0.07 mEq in the group A, 3.14 +/- 0.14 mEq in the group B, 0.25 +/- 0.03 mEq in the group C). No correlation was found between PRA, NaD-KD, NaU-KU and age in the groups examined. A significant inverse correlation was observed P-aldo, NaD (p<0.001), NaU (p<0.002), and age (p<0.01). A positive correlation was found between P-aldo and KD (p<0.005), and a borderline positive correlation between P-aldo and KU (p<0.06) for B-C groups only. PRA and P-aldo were positively correlated (p<0.002) in the three groups, when considered all together. These results suggests some considerations on RAA system in early infancy: (1) the age is probably the most important factor influencing the PRA high value in younger children; (2) Na dietary intake is certainly the most important factor influencing the P-aldo variations in the same period of life.