|The ILFI (Indagine Longitudinale sulle Famiglie Italiane) is a prospective panel survey divided into five waves. The five waves were carried out respectively in 1997, 1999, 2001, 2003 and 2005. The first survey wave gathered retrospective information on all significant events occurring to the members of the sample in the period between their births and the date of the interview. The purpose of each of the four subsequent surveys was to update this information, recording all significant events occurring to the members of the sample in the period between the previous interview and the date of the current one. This survey method offers a number of advantages to those who engage in the study of social change:
- they can examine the interdependences between education, work career and family dynamics. Not only can the occurrence of certain events be studied, but also their duration (for example, the amount of time spent in atypical employment);
- they can distinguish among life-cycle, cohort and period effects and take more adequate account of unobserved heterogeneity effects;
- they can investigate the interactions and reciprocal influences among the life-courses of the members of the same household, given that all of them are interviewed;
- the large size of the sample enables sub-populations and relatively rare events to be studied reliably.