Navigating Sample Size Estimation for Qualitative Research

Abstract

Abstract There are well-established rules and methods about sample size estimation in quantitative research approaches. However, qualitative research approaches justify very little about sample size estimation principles and largely depend on subjective judgements and arbitrariness. Contrarily, an adequate sample size is essential for a study to address the core elements of validity and credibility in qualitative research too such as rigor, trustworthiness, conformability and acceptance. Therefore, this review was carried out to explain the available methods to estimate sample size for qualitative studies. After conducting a thorough literature review, we discovered related articles that explore the estimation of sample size for qualitative studies. By examining these findings and integrating the information with our personal experience for estimation of sample size in the field of qualitative studies, we have produced an all-encompassing narrative review. After an in-depth literature search, four different approaches were described in this paper to answer the question of how to estimate sample size in qualitative studies. The four approaches described in this paper are (a) rules of thumb, (b) conceptual models, (c) concept of saturation and (d) statistics-based methods for sample size estimation in qualitative research. The paper presents four methods for estimating sample size in qualitative studies and simplifies the statistical approach for saturation calculation in qualitative studies. Yet, it is vital to responsibly integrate these methods, acknowledging their limitations and maintaining the importance of sample size estimation in qualitative studies.