Building Theories From Qualitative Interview Research: How Many Interviews Do I Need?

Abstract

Qualitative researchers seeking to understand how many interviews are required to support a robust theoretical contribution face ambiguous and often contradictory recommendations. We argue existing recommendations fall into one of three ideal-type categories: (i) a pre-determined number or range of numbers, (ii) a number informed by specific criteria, such as the research purpose and duration of the study, or (iii) a methodologically principled number rooted in epistemological assumptions. Despite longstanding tensions between these categories, there is little investigation of how differing recommendations compare with the actual number of interviews conducted in high quality scholarship. We conducted a systematic review of qualitative studies (n = 260) in top-tier management journals (AMJ, ASQ, Org. Sci., and SMJ) over a 10-year period (2010–2019). Drawing on our analysis, we demonstrate how each of the three categories of recommendations fails to explain the number of interviews reported in published articles. We develop a set of guiding questions and “guardrails” to support researchers in developing, and reviewers in respecting, differing justifications of interview sample sizes.