Nota metodologica. Le tecniche di elaborazione dei dati utilizzate

This methodological contribution came from requests to synthesize and investigate the results of a survey on third sector organizations of national importance, which operate at multiple levels. The action of the synthesis was carried out by constructing the indices, which result from some indicators related to a same size. The essay discusses some problems of these scales: the one-dimensionality, the assigning of a score to individual indicators, standardization, internal consistency and the division of the scale in multi-level, challenging some concepts, often taken for granted. The work of deepening, instead, was conducted using two techniques of multivariate analysis of totally different nature: the cluster analysis, which serves to capture the distinctive elements characterizing groups that can be observed in a population and the logistic regression, which is aimed to grasp the weight that certain independent variables have with respect to a specific dependent variable. The most thorough from the statistical point of view is the analysis of logistic regression.