The study of fertility intentions has gained importance in the literature during the last decades. Nevertheless, research focussing on their realisation is still scarce due to limited availability of longitudinal data. Although a bulk of existing studies demonstrated regional variation and...

Mixed mode designs are increasingly important in surveys and large longitudinal studies are progressively moving to or considering such a design. In this context our knowledge regarding the impact of mixing modes on data quality indicators in longitudinal studies is sparse. This study tries to...

The results of a resurvey of non-respondents to the SOEP study carried out in 2006 show that this special effort of reinterviewing was relatively ineffective in two respects. First, the rate of successful conversions of passive to active respondents was low (less than 20 percent). Second, the...

This paper is concerned with the determinants of English language proficiency (speaking, reading and writing) among immigrants. It presents a model of immigrant destination language acquisition based on economic incentives, exposure to the destination language, and efficiency in second language...

We propose a novel view of selection bias in longitudinal surveys. Such bias may arise from initial nonresponse in a probability sample, or it may be caused by self-selection in an internet survey. A contraction theorem from mathematical demography is used to show that an initial bias can...