Outline

After presenting a theoretical overview and discussing some methodological limitations of cross-sectional studies, this chapter presents three empirical aspects of BASE that are relevant to all chapters in this volume: (1) an overview of the measures used in the 14 sessions of data collection, (2) a summary of the findings of sample selectivity analyses, and (3) issues of generalizability, with a special emphasis on problems such as selective mortality and statistical weighting.

In general, the selectivity analyses indicate that the BASE data are characterized by a considerable degree of heterogeneity and generalizability. Furthermore, there is little evidence of interactions between selectivity effects and the primary design variables – that is, chronological age and gender. Furthermore, there are also few indications that sample selection processes imply major effects on information about interindividual variability and covariation among variables.