The DOI matches its Crossref record; 29 of the 29 references it cites were found in a registry or an index.
What is an adequate sample size? Operationalising data saturation for theory-based interview studies
Open accessAbstract
In interview studies, sample size is often justified by interviewing participants until reaching 'data saturation'. However, there is no agreed method of establishing this. We propose principles for deciding saturation in theory-based interview studies (where conceptual categories are pre-established by existing theory). First, specify a minimum sample size for initial analysis (initial analysis sample). Second, specify how many more interviews will be conducted without new ideas emerging (stopping criterion). We demonstrate these principles in two studies, based on the theory of planned behaviour, designed to identify three belief categories (Behavioural, Normative and Control), using an initial analysis sample of 10 and stopping criterion of 3. Study 1 (retrospective analysis of existing data) identified 84 shared beliefs of 14 general medical practitioners about managing patients with sore throat without prescribing antibiotics. The criterion for saturation was achieved for Normative beliefs but not for other beliefs or studywise saturation. In Study 2 (prospective analysis), 17 relatives of people with Paget's disease of the bone reported 44 shared beliefs about taking genetic testing. Studywise data saturation was achieved at interview 17. We propose specification of these principles for reporting data saturation in theory-based interview studies. The principles may be adaptable for other types of studies.
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“Recruitment continued until data saturation occurred, when no new information was being obtained across three consecutive interviews [34, 35].”
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“However, final sampling follows theoretical data saturation principles (100, 101).”
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“The other two references (both high cited) used to justify thematic saturation comprised an editorial in Qualitative Health Research (Morse, 1995) and an empirical study in Psychology and Health (Francis et al., 2010).”
From Human resource management in the age of generative artificial intelligence: Perspectives and research directions on ChatGPT (2023) · cites this paper as Francis et al., 2010
In the citing paper
“From discussion with the above stakeholders and guided by the literature [32] an initial sample of eight schools, four from each programme was deemed sufficient to provide adequate sample size to achieve data saturation, and to be feasible within the timelines and resources for the study.”
From Barriers, facilitators and capacities for childhood obesity prevention in 12 European nations: results of a policy-maker survey (2018) · cites this paper as [32]
In the citing paper
“Data saturation was reached following completion of interviews within the initial sample of six primary schools with no new themes emerging [32].”
From Barriers, facilitators and capacities for childhood obesity prevention in 12 European nations: results of a policy-maker survey (2018) · cites this paper as [32]
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Cites
The theory of planned behavior
Ajzen, I. (1991) · Organizational Behavior and Human Decision Processes · doi:10.1016/0749-5978(91)90020-t · Cited by 90,587
Wagner, H. R., Glaser, B. G., & Strauss, A. L. (1968) · Social Forces · doi:10.2307/2575405 · Cited by 46,525
Content Analysis: An Introduction to its Methodology.
Shelley, M., & Krippendorff, K. (1984) · Journal of the American Statistical Association · doi:10.2307/2288384 · Cited by 24,346
How Many Interviews Are Enough?: An Experiment with Data Saturation and Variability
Guest, G., Bunce, A., & Johnson, L. (2006) · Field Methods · doi:10.1177/1525822x05279903 · Cited by 20,808
Efficacy of the Theory of Planned Behaviour: A meta‐analytic review
Armitage, C. J., & Conner, M. (2001) · British Journal of Social Psychology · doi:10.1348/014466601164939 · Cited by 9,970
The Theory of Planned Behaviour
Conner, M. T., & McMillan, B. (2004) · Research Explorer (The University of Manchester) · Cited by 4,462
Webb, T. L., & Sheeran, P. (2006) · Psychological Bulletin · doi:10.1037/0033-2909.132.2.249 · Cited by 3,732
The SAGE Handbook of Grounded Theory
Bryant, A., & Charmaz, K. (2007) · SAGE · doi:10.4135/9781848607941 · Cited by 2,798 · cited 1×
“Whether the principles of data saturation that we propose are appropriate for application to other types of interview study (e.g. those using other theories, or grounded theory; Bryant & Charmaz, 2007) would require further investigation.”
Background(2004) · City Research Online (City University London) · Cited by 1,385
Self-citationDevine, C. M., Jastran, M., Jabs, J., Wethington, E., Farrell, T. J., & Bisogni, C. A. (2006) · Social Science & Medicine · doi:10.1016/j.socscimed.2006.06.029 · Cited by 327
Research works printed but not linked: 2
- Ajzen I, 1988, Attitudes, personality and behaviour
- Glaser BG, 1967, The discovery of grounded theory: Strategies for qualitative research
Cited by
Sorted by citations
Saturation in qualitative research: exploring its conceptualization and operationalization
Saunders, B., Sim, J., Kingstone, T., Baker, S., Waterfield, J., Bartlam, B., Burroughs, H., & Jinks, C. (2018) · Quality & Quantity · doi:10.1007/s11135-017-0574-8 · Cited by 12,033
“…led some commentators to argue for the need for qualitative researchers to provide a more thorough and transparent reporting of how they achieved saturation in their research, thus allowing readers to assess the validity of this claim (Bowen 2008; Francis et al. 2010), our arguments go beyond this.”
BackgroundInfluentialSample sizes for saturation in qualitative research: A systematic review of empirical tests
Hennink, M., & Kaiser, B. N. (2022) · Social Science & Medicine · doi:10.1016/j.socscimed.2021.114523 · Cited by 6,311
Braun, V., & Clarke, V. (2021) · Qualitative Research in Sport, Exercise and Health · doi:10.1080/2159676x.2019.1704846 · Cited by 4,776
Code Saturation Versus Meaning Saturation: How Many Interviews Are Enough?
Hennink, M. M., Kaiser, B. N., & Marconi, V. C. (2017) · Qualitative Health Research · doi:10.1177/1049732316665344 · Cited by 4,597
“Our study responds to calls for more methodological research on operationalizing saturation (by Francis et al., 2010; Guest et al., 2006; Morse, 2015).”
BackgroundMethodResultInfluentialAre We There Yet? Data Saturation in Qualitative Research
Fusch, P., & Ness, L. (2015) · The Qualitative Report · doi:10.46743/2160-3715/2015.2281 · Cited by 4,460
Metadata
- Authors
- Francis, J. J., Johnston, M., Robertson, C., Glidewell, L., Entwistle, V., Eccles, M. P., & Grimshaw, J. M.
- Affiliations
- University of Aberdeen (GB)
- University of Dundee (GB)
- Newcastle University (GB)
- University of Ottawa (CA)
- Corresponding author
- Francis, Jill J.
- ORCID
- Venue
- Psychology & Health
- Publisher
- Informa UK Limited
- Published
- 2010-12
- Volume
- 25
- Issue
- 10
- Pages
- 1229-1245
- ISSN
- 0887-0446 (ISSN-L)
- 1476-8321
- OpenAlex
- W1971765404
- Cited by
- 3,429
- References
- 29
- Citations by year
- 2026: 343 · 2025: 405 · 2024: 444 · 2023: 333 · 2022: 332 · 2021: 359 · 2020: 219 · 2019: 215 · 2018: 187 · 2017: 159 · 2016: 147 · 2015: 116 · 2014: 72 · 2013: 57 · 2012: 27
- FWCI
- 56.55
- Type
- journal article
- Language
- en
- Open access
- green
- hdl.handle.net
- Locations
- Psychology and Health (publishedVersion)
- PubMed (publishedVersion)
- City Research Online (City University London) (acceptedVersion)
- Aberdeen University Research Archive (Aberdeen University) (submittedVersion)
- Discovery Research Portal (University of Dundee) (submittedVersion)
- Newcastle University ePrints (Newcastle Univesity)
- Funders
- Scottish Government
- Chief Scientist Office, Scottish Government Health and Social Care Directorate
- Medical Research Council
- Topics
- Social Sciences › Education › Qualitative Research Methods and Applications
- Social Sciences › Sociology and Political Science › Focus Groups and Qualitative Methods
- Social Sciences › Sociology and Political Science › Qualitative Research Methods and Ethics
- Keywords
- data saturation, sample size determination, qualitative research reporting, stopping rules, theory of planned behavior, shared beliefs, general practitioners, Paget's disease, genetic testing, relatives
- MeSH terms
- Adult, Anti-Bacterial Agents, Attitude of Health Personnel, Culture, Data Collection, England, Female, Genetic Testing, Humans, Interview, Psychological, Male, Osteitis Deformans, Pharyngitis, Psychometrics, Scotland, Observer Variation, Sample Size, Biomedical Research, General Practice
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