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Abstract

The methods literature regarding sampling in qualitative research is characterized by important inconsistencies and ambiguities, which can be problematic for students and researchers seeking a clear and coherent understanding. In this article we present insights about sampling in qualitative research derived from a systematic methods overview we conducted of the literature from three research traditions: grounded theory, phenomenology, and case study. We identified and selected influential methods literature from each tradition using a purposeful and transparent procedure, abstracted textual data using structured abstraction forms, and used a multistep approach for deriving conclusions from the data. We organize the findings from this review into eight topic sections corresponding to the major domains of sampling identified in the review process: definitions of sampling, usage of the term sampling strategy, purposeful sampling, theoretical sampling, sampling units, saturation, sample size, and the timing of sampling decisions. Within each section we summarize how the topic is characterized in the corresponding literature, present our comparative analysis of important differences among research traditions, and offer analytic comments on the findings for that topic. We identify several specific issues with the available guidance on certain topics, representing opportunities for future methods authors to improve our collective understanding.

Keywords

Qualitative Research Methods, Sampling, Grounded Theory, Phenomenology, Case Study, Methods Literature, Literature Review, Systematic Review, Systematic Methods Overview

Author Bio(s)

Stephen J. Gentles, MSc, PhD, is a postdoctoral fellow in the CanChild Centre for Childhood Disability Research at McMaster University. Correspondence regarding this article can be addressed directly to: Stephen J. Gentles at, CanChild, McMaster University, 1400 Main Street West, IAHS 408, Hamilton, ON, L8S 1C7, Canada, stevegentles@gmail.com.

Cathy Charles, PhD, is professor emeritus in the Department of Clinical Epidemiology & Biostatistics, and member of the Centre for Health Economics and Policy Analysis (CHEPA) at McMaster University. Correspondence regarding this article can also be addressed directly to: Cathy Charles at, Department of Clinical Epidemiology & Biostatistics, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada, charlesc@mcmaster.ca.

Jenny Ploeg, BScN, PhD, is professor in the School of Nursing, and member of the Aging, Community and Health Research Unit (ACHRU) at McMaster University. Correspondence regarding this article can also be addressed directly to: Jenny Ploeg at, School of Nursing, McMaster University, 1280 Main Street West, Rm HSC 3N25C, Hamilton, Ontario, L8S 4K1, Canada, ploegj@mcmaster.ca.

K. Ann McKibbon, MLS, PhD, is professor emeritus in the Department of Clinical Epidemiology & Biostatistics, director of the eHealth Program, and member of the Health Information Research Unit (HIRU) at McMaster University. Correspondence regarding this article can also be addressed directly to: K. Ann McKibbon at, Department of Clinical Epidemiology & Biostatistics, McMaster University, 1280 Main Street West, CRL 132, Hamilton, ON, L8S 4K1, Canada, mckib@mcmaster.ca.

Publication Date

11-9-2015

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.

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