Is There a Doctor on Board? Collecting Generalizable Data on Doctoral Candidates in Germany

Despite of its relevance for science policy and the scientific community, empirical research on doctoral education in Germany is sparse. The few papers available face challenges in the sampling approach: simple random sampling is not possible, because a universal register of PhD candidates in Germany does not exist yet. This article focuses on the issues related to possible data collections for the purpose of research with respect to PhD candidates in Germany. We first outline which official information on doctoral candidates is currently available. We then give an overview of the main German survey studies on doctoral candidates with a focus on their respective sampling strategies. Finally, we discuss the three approaches which conceivably enable researchers to conduct statistical inference on the population of doctoral candidates in Germany: sampling via stratified clusters based on universities or faculties, sampling based on a screening approach, and respondent driven sampling