For some of the ISSP topic series, cumulated data sets are available. They are designed to facilitate comparative analyses over time. Combining three, four or even four points of time, these datasets cover up to 31 years of social attitudes and behavior. Database for such a trend file are all ISSP member countries that participated in the module topic at least two times. Cumulated variables are all substantial variables, which were asked at least two times and all demography variables for the countries included. For each cumulated data set a specific guideline document provides detailed information on variables and cumulation procedure.