The stratification variables related to the level of education and occupational status were set as “soft quotas”, that is, a margin of oscillation was allowed around the predefined strata size required. In setting the theoretical sample, it was further decided to opt for non-proportional distribution in relation to the universe, for the demographic variables of gender by age groups, level of education, and occupational status. The reason was to facilitate the interpretation of the data (. by increasing the sample size of strata which otherwise would be very small) and on the other it maintained homogeneity between the various countries,.
