The logic of small samples in interview-based qualitative research

In a qualitative framework, research based on interviews often seeks to penetrate social life beyond appearance and manifest meanings. This requires the researcher to be immersed in the research field, to establish continuing, fruitful relationships with respondents and through theoretical contemplation to address the research problem in depth. Therefore a small number of cases (less than 20, say) will facilitate the researcher’s close association with the respondents, and enhance the validity of fine-grained, in-depth inquiry in naturalistic settings. Epistemologically prior to these considerations, however, is the explanatory status of such research. From a realist standpoint, here concept formation through induction and analysis aims to clarify the nature of some specific situations in the social world, to discover what features there are in them and to account, however partially, for those features being as they are. Since such a research project scrutinizes the dynamic qualities of a situation (rather than elucidating the proportionate relationships among its constituents), the issue of sample size - as well as representativeness - has little bearing on the project’s basic logic. This article presents this argument in detail, with an example drawn from a study of persons with a past history of cancer diagnosis and treatment.