Where, What and Whom to Study? Principles, Guidelines and Empirical Examples of Case Selection and Sampling in Migration Research

Abstract

Case selection, or sampling, is central for social scientific knowledge production, as the question of which people or incidents to include in a study largely influences the validity and generalization of results. In contrast to random methods of sampling, the purposive character of case selection in qualitative research requires researchers reflecting systematically on which cases to select for their research. Most importantly researchers need to constantly ask themselves: What is the case a case of? Qualitative methodology suggests different strategies to identifying cases which are appropriate for specific research topics, designs and theoretical perspectives. This chapter presents some guidance by cataloguing different types of case selection, i.e. purposive sampling, snowball sampling, theoretical sampling, and matched sampling, and their application in selected empirical studies in migration research. Moreover, this chapter discusses the merits and disadvantages of these methods, in particular in relation to the previously addressed critiques toward migration research, most importantly methodological nationalism and overemphasizing ethnicity.