Given that older adults have been ignored in the research concerning suntanning, fair-skinned older adults are the most likely to experience skin cancer, and women privilege appearance over health when it comes to sunbathing practices, our study offers depth and richness of data in a demographic group much in need of research attention. Whilst achieving a large sample size was sometimes viewed positively because it led to richer results, there were also occasions when a large sample size was problematic rather than desirable. Google Scholar. There was no association between the number of interviews (i.e. Saunders MN, Townsend K. Reporting and justifying the number of interview participants in organization and workplace research.

Qual Health Res. Qual Res Psychol. Naturalistic inquiry. These data may be seen as an opportunity to generate further hypotheses and are a unique application of the medicalisation framework. JB and TY conceived the study; KV, JB, and TY designed the study; KV identified the articles and extracted the data; KV and JB assessed eligibility of articles; KV, JB, ST, and TY contributed to the analysis of the data, discussed the findings and early drafts of the paper; KV developed the final manuscript; KV, JB, ST, and TY read and approved the manuscript. interview studies nested in a trial, as part of a broader ethnography, as part of a longitudinal research) were included if they reported only single-time qualitative interviews. As such, care should be taken not to overstate the findings. 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. Qual Health Res. The first of these relates to the small number of respondents who took part in the study. 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. The final sample size was determined by thematic saturation, the point at which new data appears to no longer contribute to the findings due to repetition of themes and comments by participants (Morse, 1995). Seven of the 19 SHI articles cited references to support their position on saturation (see AdditionalFile4 for the full list of citations used by articles to support their position on saturation across the three journals). Qual Health Res. volume18, Articlenumber:148 (2018) studies that quantified their qualitative data were excluded). grounded theory, phenomenology [11, 41]. Claims of saturation were sometimes supported with citations of other literature, suggesting a removal of the concept away from the characteristics of the study at hand. No new topics were identified following analysis of approximately two thirds of the interviews; however, all interviews were coded in order to develop a better understanding of how characteristic the views and reported behaviours were, and also to collect further examples of unusual/deviant observations. Sandelowski M. Real qualitative researchers do not count: the use of numbers in qualitative research. Meeting sampling requirements (7.2% of all justifications) was another argument employed by two BMJ and four SHI articles to explain their sample size. (BJHP38). In Proceedings of the 2016 CHI conference on human factors in computing systems. (BJHP53). Sample size in grounded theory cannot be determined a priori as it is contingent on the evolving theoretical categories. The relatively low response rate was anticipated, due to the busy life-styles of young people in the age range, the geographical constraints, and the time required to participate in a semi-structured interview, so a larger target sample allowed a sufficient number of participants to be recruited. that moved beyond description. We note, first, the limited number of health-related journals reviewed, so that only a snapshot of qualitative health research has been captured. 0000001752 00000 n This number was not fixed in advance, but was guided by the sampling strategy and the judgement, based on the analysis of the data, of the point at which category saturation was achieved. We believe that such an analysis would yield useful insights as it links the methodological issue of sample size to the broader philosophical stance of the research. New York: Macmillan; 1986. p. 11961. 0000011904 00000 n The analysis showed that there were three main characterisations of the sample size in the articles that provided relevant comments and discussion: (a) the vast majority of these qualitative studies (n=42) considered their sample size as small and this was seen and discussed as a limitation; only two articles viewed their small sample size as desirable and appropriate (b) a minority of articles (n=4) proclaimed that their achieved sample size was sufficient; and (c) finally, a small group of studies (n=5) characterised their sample size as large. 2nd ed. Glaser BG, Strauss AL. The determination of sample size on the basis of pragmatic considerations was the second most frequently invoked argument (9.6% of all justifications) appearing in all three journals. 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. In total, 214 articles 21 in the BMJ, 53 in the BJHP and 140 in the SHI were eligible for inclusion in the review. A comparative method for themes saturation (CoMeTS) has also been suggested [23] whereby the findings of each new interview are compared with those that have already emerged and if it does not yield any new theme, the saturated terrain is assumed to have been established. .fCjYtf7#qYPcgU/:n[{/pYu.}3oH>c5|M' j \b`H :/( Qualitative sample sizes were predominantly and often without justification characterised as insufficient (i.e., small) and discussed in the context of study limitations. Malterud K, Siersma VD, Guassora AD. Sandelowski M. Sample size in qualitative research. non-representativeness, biases, self-selection) or anticipated that they might be criticized for their small sample size. Thomson SB. A minority of articles discussed how sample-related limitations (with the latter most often concerning the type of sample, rather than the size) limited generalizability. Sample size in qualitative interview studies: guided by information power. Because the order in which interviews are analysed can influence saturation thresholds depending on the richness of the data, Constantinou et al. Defence of sample size was most frequently supported across all three journals with reference to the principle of saturation and to pragmatic considerations. However, the emphasis changes from an in-depth individualistic analysis to one in which common themes from shared experiences of a group of people can be elicited and used to understand the network of relationships between themes that emerge from the interviews. Marshall MN. Thirty three women were approached to take part in the interview study. 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. 0000012498 00000 n Pairwise comparisons following a significant Kruskal-WallisFootnote 2 test indicated that the studies published in the BJHP had significantly (p<.001) smaller samples sizes than those published either in the BMJ or the SHI. These thirty, from which we draw our findings, were chosen for translation based on heterogeneity in depressive symptomology and educational attainment. (SHI23). Fam Pract. 0000001969 00000 n (BMJ13). Two articles reported pre-determining their sample size with a view to achieving data saturation (BMJ08 see extract in section In line with existing research; BMJ15 see extract in section Pragmatic considerations) without further specifying if this was achieved. Twenty-three people with type I diabetes from the target population of 133 (i.e. https://doi.org/10.1186/s12874-018-0594-7, DOI: https://doi.org/10.1186/s12874-018-0594-7. Expert Rev Med Devices. When in doubt, discussions about retaining or excluding articles were held between KV and JB in regular meetings, and decisions were jointly made. The past decade has seen a growing appetite in qualitative research for an evidence-based approach to sample size determination and to evaluations of the sufficiency of sample size. These narratives were evident both in papers that justified their sample size and those that did not. 0000007668 00000 n Google Scholar. Beyond such guidance, specific numerical recommendations have also been proffered, often based on experts experience of qualitative research. We next review the existing conceptual and empirical literature on sample size determination. Whilst the quantitative research community has established relatively straightforward statistics-based rules to set sample sizes precisely, the intricacies of qualitative sample size determination and assessment arise from the methodological, theoretical, epistemological, and ideological pluralism that characterises qualitative inquiry (for a discussion focused on the discipline of psychology see [12]). (BMJ13). Guest G, Bunce A, Johnson L. How many interviews are enough? (SHI35). Two articles explicitly stated that they did not achieve saturation; instead claiming a level of theme completeness (BJHP27) or that themes being replicated (BJHP53) were arguments for sufficiency of their sample size. For greater transparency, Francis et al. Clarity and sharpness of emerging themes and alignment with previous relevant work were the arguments employed to warrant the validity of the results. [25] reached data saturation at the 17th interview for all their pre-determined theoretical constructs. Braun V, Clarke V. (Mis) conceptualising themes, thematic analysis, and other problems with Fugard and Potts (2015) sample-size tool for thematic analysis. Qual Res. 29], specific numbers at which saturation was achieved within these projects cannot be routinely extrapolated for other projects. Int J Soc Res Methodol. Hays DG, Wood C, Dahl H, Kirk-Jenkins A. Methodological rigor in journal of counseling & development qualitative research articles: a 15-year review. 0000013041 00000 n 0000003258 00000 n L X kFAd F%%d.KhXZ0`qI$ Morse JM. A thematic analysis [55] was then performed on all scientific narratives that discussed or commented on the sample size of the study. This study used rich data provided by a relatively large sample of expert informants on an important but under-researched topic.

Four BJHP studies, all adopting IPA, expressed the appropriateness or desirability of small sample sizes (BJHP41; BJHP45) or hastened to explain why they included a larger than typical sample size (BJHP32; BJHP47). London: Sage; 2006. 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. 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. Qual Health Res. Ogden J, Cornwell D. The role of topic, interviewee, and question in predicting rich interview data in the field of health research. The second major concern that arose from a small sample size pertained to the internal validity of findings (i.e. ACM. Although our numbers were too small to demonstrate gender differences with any certainty, it does seem that the biomedical and erotic scripts may be more common in the accounts of men and the relational script more common in the accounts of women. The present research, therefore, incorporates a comparative element on the basis of three different disciplines engaging with qualitative health research: medicine, psychology, and sociology. In a theory-driven content analysis, Francis et al. 2011;11(1):26. Chicago, IL: Aldine; 1967. Qual Quant. The level of analysis i.e. This sample size justification (8.4% of all justifications) was mainly employed by BJHP articles and referred to an intensive, idiographic and/or latently focused analysis, i.e. We drew participants from a list of prisoners who were scheduled for release each week, sampling them until we reached the target of 35 cases, with a view to achieving data saturation within the scope of the study and sufficient follow-up interviews and in line with recent studies [810]. 2017;27(4):591608. Qual Res. Konstantina Vasileiou. 0000015417 00000 n (BJHP28). generalisation that can be made from and about cases [5]). Finally, SHI112 (see extract in section Further sampling to check findings consistency) argued that it achieved saturation of discursive patterns. In: Wittrock M, editor. They noted that their sample was relatively homogeneous, their research aims focused, so studies of more heterogeneous samples and with a broader scope would be likely to need a larger size to achieve saturation. She invites researchers to take into account parameters, such as the scope of study, the nature of topic (i.e. How theory is used and articulated in qualitative research: development of a new typology. 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. Onwuegbuzie AJ. (BJHP31). We would like to thank Dr. Paula Smith and Katharine Lee for their comments on a previous draft of this paper as well as Natalie Ann Mitchell and Meron Teferra for assisting us with data extraction. Indicative of an apparent oscillation of qualitative researchers between the different requirements and protocols demarcating the quantitative and qualitative worlds, there were a few instances of articles which briefly recognised their small sample size as a limitation, but then defended their study on more qualitative grounds, such as their ability and success at capturing the complexity of experience and delving into the idiographic, and at generating particularly rich data. 2007;41(1):10521.

2017;17(5):57188. Whilst the themes from the initial interviews seemed to be replicated in the later interviews, further interviews may have identified additional themes or provided more nuanced explanations. Once this sample had been analysed, one further interview from each age-stratified group was randomly chosen to check for consistency of the findings.

Sitemap 34