Like many medical studies, the Berlin Aging Study II (BASE-II) is based on a non-random "convenience sample" of self-recruited participants. To study processes of selectivity in BASE-II, we used an identical questionnaire to compare BASE-II with a large, representative reference study, the...

Since it is still unclear to what extent time allocation retrospectively reported in questionnaires, reflects people's actual behavior, examining the accuracy of responses to time use survey questions is of crucial importance. We analyze the congruence of time use information assessed through...

In this paper we discuss the rationale for tracing non-original sample members (Non-OSMs) in household panel studies, and in particular in SOEP, and the implications for weighting. We present results on the incidence, survival rates, and thus the relevance of Non-OSMs in the SOEP.