Unit nonresponse errors in income surveys: a case study

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 the 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.     

Unemployment Duration: An Analysis of Incomplete,Completed, and Multiple Spells in Emilia-Romagna

Sets of incomplete and completed spells of unemployment wereobtained 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 modelwith a Weibull specification of the baseline hazard, includingboth unobserved heterogeneity applied to the scale parameterof the duration distribution, and telescoping effect to accountfor spikes in the distribution of unemployment spells.They were compared formally also with a non-proportional hazardmodel based on a log-logistic distribution of duration.The estimation of the parameters was carried out separately on bothcompleted spells and quarterly incomplete spells to ascertaindifferences 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 statisticallystable over time and were also equal to the parameters ofthe completed spells model.Therefore, the analysis of incomplete spells is fairly feasiblewhen an even (closed form) baseline hazard function is suitablefor data.     

Ordinal scales and fuzzy set systems to measure agreement: An application to the evaluation of teaching activity

Student evaluation of university teaching activity is now compulsory in Italy and a research group of the ItalianMinistry 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.This study is a part of the project Methods and technology for innovating and re-organising teaching activity supported by the University of Modena and Reggio Emilia.