Since the year 2003, SOEP has been systematically adding to its repertoire of survey instruments in the area of early childhood. The present study reports on the instrumental value of a 20-item "mother questionnaire" on the adaptive behavior of their two to three-year-old children (VABS) in the...

Design-based estimators of totals, means or proportions in finite populations generally are functions of weighted sums. If each element selected into the sample is also observed, then for the calculation of the pi-estimator these weights are just the inverse inclusion probabilities of the...