0000015417 00000 n Cookies policy. Often unjustified (and in two cases incongruent with their own claims of saturation) these findings imply that sample size in qualitative health research is often adversely judged (or expected to be judged) against an implicit, yet omnipresent, quasi-quantitative standpoint. it should be acknowledged that this study was based on a small sample of self-selected couples in enduring marriages who were not broadly representative of the population. We concur with existing views [11, 36] that the consideration of the characteristics of the study at hand, such as the epistemological and theoretical approach, the nature of the phenomenon under investigation, the aims and scope of the study, the quality and richness of data, or the researchers experience and skills of conducting qualitative research, should be the primary guide in determining sample size and assessing its sufficiency. Nevertheless, research shows that sample size sufficiency reporting is often poor, if not absent, across a range of disciplinary fields. As such, care should be taken not to overstate the findings. BMJ21 (see extract in section Qualities of the analysis) and SHI32 referred to the richness, detailed nature, and volume of data collected (2.3% of all justifications) to justify the sufficiency of their sample size. Moreover, and with the rise of qualitative research in social sciences, efforts to synthesise existing evidence and assess its quality are obstructed by poor reporting [58, 59]. Data were saturated. 30, 35], might be based on research that does not provide adequate evidence of sample size sufficiency. qualitative Saunders B, Sim J, Kingstone T, Baker S, Waterfield J, Bartlam B, et al. Hays DG, Wood C, Dahl H, Kirk-Jenkins A. Methodological rigor in journal of counseling & development qualitative research articles: a 15-year review. London: Sage; 1985. These articles, all published in the discipline of sociology, defended their findings in terms of the possibility of drawing logical and conceptual inferences to other contexts and of generating understanding that has the potential to advance knowledge, despite their small size. Nurs Health Sci. Saturation in qualitative research: exploring its conceptualization and operationalization. (BJHP50). Determination of sample size so that it is in line with, and serves the requirements of, the research design (2.3% of all justifications) that the study adopted was another justification used by 2 BMJ papers (BMJ16; BMJ08 see extract in section In line with existing research). Focusing on single-interview-per-participant qualitative designs, the present study aims to further contribute to the dialogue of sample size in qualitative research by offering empirical evidence around justification practices associated with sample size. (SHI139). Mixed method studies and articles reporting more than one qualitative method of data collection (e.g. Additionally, this study attempted to expand previous empirical investigations by examining how qualitative sample sizes are characterised and discussed in academic narratives. The sample therefore is unlikely to represent the full spectrum of patients, particularly those who are not referred to, or who have been discharged from dental services. 2004;31(1):921. Transforming qualitative information: thematic analysis and code development. In particular, patients were only recruited from secondary care services where COFP diagnoses are typically confirmed. 0000003859 00000 n Despite increasing attention to rigor in qualitative research (e.g. data, theoretical, thematic saturation) (SHI04; SHI13; SHI30) whilst another four articles explicitly stated that they achieved saturation (SHI100; SHI125; SHI136; SHI137). Our numbers are small because negotiating access to social networks was slow and labour intensive, but our methods generated exceptionally rich data. Accessed 17 May 2018. Sociol Health Illn. On the basis of this analysis, the categories that expressed qualitatively different sample size justifications were developed. Patton MQ. respondents ict Though not always explicitly articulated to what form of generalisation the articles referred to (see BJHP09), generalisation was mostly conceived in nomothetic terms, that is, it concerned the potential to draw inferences from the sample to the broader study population (representational generalisation see BJHP31) and less often to other populations or cultures. 0000006641 00000 n Hsieh HF, Shannon SE. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Creswell JW.

Beyond such guidance, specific numerical recommendations have also been proffered, often based on experts experience of qualitative research. Lincoln YS, Guba EG. Charmaz K. Constructing grounded theory: a practical guide through qualitative analysis. Interviewing continued until we deemed data saturation to have been reached (the point at which no new themes were emerging). 2000;10(1):35. Int J Soc Res Methodol. Data collection ceased on pragmatic grounds rather than when no new information appeared to be obtained (i.e., saturation point). Hammersley M. Sampling and thematic analysis: a response to Fugard and Potts. respondents reproductive quantitative matrilineal Newbury Park, CA: Sage; 1990. van Rijnsoever FJ. Figure2 depicts the number of eligible articles published each year per journal. Guetterman [27] also examined health-related literature but this analysis was restricted to 26 most highly cited articles published over a period of five years whilst Carlsen and Glentons [22] study concentrated on focus groups health research. 2014;120:13541. Providing a sample size justification was not related to the number of interviews conducted, but it was associated with the journal that the article was published in, indicating the influence of disciplinary or publishing norms, also reported in prior research [30]. This resulted in a sample of 67 interviews. Saturation was the most commonly invoked principle (55.4% of all justifications) deployed by studies across all three journals to justify the sufficiency of their sample size. Manage cookies/Do not sell my data we use in the preference centre. Book The Abstract, Methods and Discussion (and/or Conclusion) sections of each article were examined by one author (KV) who extracted all the relevant information. Fusch PI, Ness LR. respondents pesticides epa labels implications cont findings quantitative research ingredient said base shopping while 0000008357 00000 n Luborsky MR, Rubinstein RL. Sandelowski M. Real qualitative researchers do not count: the use of numbers in qualitative research. Ritchie et al. 2010;25(10):122945. 0000029575 00000 n We stopped recruitment when we reached 3035 interviews, owing to the depth and duration of interviews, richness of data, and complexity of the analytical task. 2nd ed. To strengthen the explanation for choosing a non-normative sample size, previous IPA research citing a similar sample size approach is used as a precedent.

Pragmatic considerations, such as resource constraints or participant response rate and availability, was the second most frequently used argument accounting for approximately 10% of justifications and another 23% of justifications also represented intrinsic-to-the-study characteristics (i.e. ACM Trans Comput Hum Interact. It has previously been recommended that qualitative studies require a minimum sample size of at least 12 to reach data saturation (Clarke & Braun, 2013; Fugard & Potts, 2014; Guest, Bunce, & Johnson, 2006) Therefore, a sample of 13 was deemed sufficient for the qualitative analysis and scale of this study. (BJHP09). 0000002606 00000 n Indeed there were a few instances in our data where authors appeared, possibly in response to reviewers, to resist to some sort of quantification of their results. Researchers have proposed 30 as an approximate or working number of interviews at which one could expect to be reaching theoretical saturation when using a semi-structured interview approach (Morse 2000), although this can vary depending on the heterogeneity of respondents interviewed and complexity of the issues explored. (SHI35). Thousand Oaks, CA: Sage; 1998. (SHI23). BJHP studies provided a sample size justification significantly more often than would be expected (z=2.9); SHI studies significantly less often (z=2.4). BMJ. The present study sought to enrich existing systematic analyses of the customs and practices of sample size reporting and justification by focusing on qualitative research relating to health. BJHP47 explicitly renounced the notion of saturation within an IPA approach. Guest, Bunce, and Johnson [26] analysed 60 interviews and found that saturation of themes was reached by the twelfth interview. pension quantitative easing Although IPA generally involves intense scrutiny of a small number of transcripts, it was decided to recruit a larger diverse sample as this is the first qualitative study of this population in the United Kingdom (as far as we know) and we wanted to gain an overview. 2015;25(5):5878. (SHI57). respondents The review process should support authors to exercise nuanced judgments in decisions about sample size determination in the context of the range of factors that influence sample size sufficiency and the specifics of a particular study. conversation analysis, [49]; phenomenological research, [50]) whilst others reject the concept altogether [19, 51]. Terms and Conditions, Only one article (SHI30) used the term transferability to argue for the potential of wider relevance of the results which was thought to be more the product of the composition of the sample (i.e. h1 01J\Ax'MF[!.

Onwuegbuzie AJ. To examine the kinds of sample size justifications provided by articles, an inductive content analysis [54] was initially conducted. Qual Health Res. Although researchers might find sample size community norms serve as useful rules of thumb, we recommend methodological knowledge is used to critically consider how saturation and other parameters that affect sample size sufficiency pertain to the specifics of the particular project. (SHI127). 0000009139 00000 n It is an important consideration in evaluations of the quality and trustworthiness of much qualitative research [1] and is implicated particularly for research that is situated within a post-positivist tradition and retains a degree of commitment to realist ontological premises in appraisals of validity and generalizability [2,3,4,5]. We aimed for diverse, maximum variation samples [20] totalling 80 respondents from different social backgrounds and ethnic groups and those bereaved due to different types of suicide and traumatic death. How many interviews are enough to identify metathemes in multisited and cross-cultural research? Sampling in qualitative research: rationale, issues. (BJHP03). Nelson J. Spencer L, Ritchie J, Lewis J, Dillon L. Quality in qualitative evaluation: a framework for assessing research evidence. Guest G, Bunce A, Johnson L. How many interviews are enough? Manen M, Higgins I, Riet P. A conversation with max van Manen on phenomenology in its original sense. Boyatzis RE. A data extraction form was developed (see AdditionalFile3) recording three areas of information: (a) information about the article (e.g. Overall, it is clear that the concept of saturation encompassed a wide range of variants expressed in terms such as saturation, data saturation, thematic saturation, theoretical saturation, category saturation, saturation of coding, saturation of discursive themes, theme completeness. (BJHP16). 1995;311(6999):2513. The respondents quotes drawn on below were chosen as representative, and illustrate saturated themes. Similarly if published in the BMJ, the odds of a study justifying its sample size were 4.5 times higher than in the SHI. Soc Sci Med. (BJHP31). J Couns Dev. Article (BJHP13). Other articles appeared to accept and acknowledge that their sample was flawed because of its small size (as well as other compositional deficits e.g. quantitative telephone Data pertinent to sample size were extracted and analysed using qualitative and quantitative analytic techniques.

nursing sciences) as well as inter-disciplinary journals would add to the findings of this analysis. In other instances, articles attempted to preserve a degree of credibility of their results, despite the recognition that the sample size was small. (BJHP41). Robinson OC. Similarly, Britten [40] notes that large interview studies will often comprise of 50 to 60 people. Qualitative evaluation and research methods. In total, 214 articles 21 in the BMJ, 53 in the BJHP and 140 in the SHI were eligible for inclusion in the review. 2013;20(5):29. Greenhalgh T, Annandale E, Ashcroft R, Barlow J, Black N, Bleakley A, et al. 2010;5(1). respondents matrilineal quantitative reproductive Forum Qual Soc Res 2010;11(3):8. http://nbn-resolving.de/urn:nbn:de:0114-fqs100387. Critiquing the concept of saturation, Nelson [19] proposes five conceptual depth criteria in grounded theory projects to assess the robustness of the developing theory: (a) theoretical concepts should be supported by a wide range of evidence drawn from the data; (b) be demonstrably part of a network of inter-connected concepts; (c) demonstrate subtlety; (d) resonate with existing literature; and (e) can be successfully submitted to tests of external validity. Extending the enquiry to multi-site, cross-cultural research, Hagaman and Wutich [28] showed that sample sizes of 20 to 40 interviews were required to achieve data saturation of meta-themes that cut across research sites. %PDF-1.4 % For example, BJHP32 below provides a rationale for how an IPA study can accommodate a large sample size and how this was indeed suitable for the purposes of the particular research. Borsci S, Macredie RD, Barnett J, Martin J, Kuljis J, Young T. Reviewing and extending the five-user assumption: a grounded procedure for interaction evaluation. Britten N. Qualitative research: qualitative interviews in medical research. The authors further proposed two main principles upon which specification of saturation be based: (a) researchers should a priori specify an initial analysis sample (e.g. Qual Quant. statement and We had aimed to continue interviewing until we had reached saturation, a point whereby further data collection would yield no further themes. Field Methods. A systematic analysis of single-interview-per-participant designs within three health-related journals from the disciplines of psychology, sociology and medicine, over a 15-year period, was conducted to examine whether and how sample sizes were justified and how sample size was characterised and discussed by authors. Springer Nature. This mitigates against clear-cut guidelines, invariably applied. (SHI131). Recruitment and analysis ceased once theoretical saturation was reached in the categories described below (Lincoln and Guba 1985). Despite these challenges, various conceptual developments have sought to address this issue, with guidance and principles [4, 10, 11, 13,14,15,16,17,18,19,20], and more recently, an evidence-based approach to sample size determination seeks to ground the discussion empirically [21,22,23,24,25,26,27,28,29,30,31,32,33,34,35]. Qual Res. Finally, SHI112 (see extract in section Further sampling to check findings consistency) argued that it achieved saturation of discursive patterns. Morse JM. Indeed, the level of structure of questions in qualitative interviewing has been found to influence the richness of data generated [37], and so, requires attention; empirical research shows that open questions, which are asked later on in the interview, tend to produce richer data [37].