Browsing by Person "Sim, Julius"

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Can sample size in qualitative research be determined a priori?
(Informa UK Limited, 2018-03-27) Sim, Julius; Saunders, Benjamin; Waterfield, Jackie; Kingstone, Tom
There has been considerable recent interest in methods of determining sample size for qualitative research a priori, rather than through an adaptive approach such as saturation. Extending previous literature in this area, we identify four distinct approaches to determining sample size in this way: rules of thumb, conceptual models, numerical guidelines derived from empirical studies, and statistical formulae. Through critical discussion of these approaches, we argue that each embodies one or more questionable philosophical or methodological assumptions, namely: a nave realist ontology; a focus on themes as enumerable 'instances', rather than in more conceptual terms; an incompatibility with an inductive approach to analysis; inappropriate statistical assumptions in the use of formulae; and an unwarranted assumption of generality across qualitative methods. We conclude that, whilst meeting certain practical demands, determining qualitative sample size a priori is an inherently problematic approach, especially in more interpretive models of qualitative research.
Focus group methodology: Some ethical challenges
(Springer, 2019-07-16) Sim, Julius; Waterfield, Jackie
Focus group methodology generates distinct ethical challenges that do not correspond fully to those raised by one-to-one interviews. This paper explores, in both conceptual and practical terms, three key issues: consent; confidentiality and anonymity; and risk of harm. The principal challenge in obtaining consent lies in giving a clear account of what will take place in the group, owing to unpredictability of the discussion and interaction that will occur. As consent can be seen in terms of creating appropriate expectations in the participant, this may therefore be hard to achieve. Moreover, it is less straightforward for the participant to revoke consent than in one-to-one interviews. Confidentiality and anonymity are potentially problematic because of the researcher’s limited control over what participants may subsequently communicate outside the group. If the group discussion encourages over-disclosure by some participants, this problem becomes more acute. Harm in a focus group may arise from the discussion of sensitive topics, and this may be amplified by the public nature of the discussion. A balance should be struck between avoiding or closing down potentially distressing discussion and silencing the voices of certain participants to whom such discussion may be important or beneficial. As a means of addressing the above issues, we outline some strategies that can be adopted in the consent process, in a preliminary briefing session, during moderation of the focus group, and in a subsequent debriefing, and suggest that these strategies can be employed synergistically so as to reinforce each other.
Intra-individual variations in the bifurcation of the radial nerve and the length of the posterior interosseous nerve
(2011-09-07) Benham, Alex; Introwicz, Barbara; Waterfield, Jackie; Sim, Julius; Derricott, Hayley; Mahon, Mike
Anatomical literature on the radial nerve predominantly features inter-individual variations, with comparatively few studies investigating intra-individual variations. The radial nerve has a complex and variable course, particularly in relation to the location at which the nerve bifurcates to form the superficial branch of the radial nerve and the posterior interosseous nerve. Variations of the radial nerve may change the way the nerve and its branches, their blood supply and nerve transmission respond to forces. This study investigated the presence of intra-individual differences in the bifurcation point of the radial nerve and the length of the posterior interosseous nerve from the bifurcation to the radial tunnel. Eighteen embalmed human cadavers were dissected to reveal the radial nerve. Measurements were taken from the level of the lateral humeral epicondyle to the bifurcation of the radial nerve, and from the bifurcation to the radial tunnel. All cadavers presented with intra-individual variations between the left and right limbs. Significant differences were found between the left and right limbs for the measurement from the lateral humeral epicondyle to the bifurcation (median difference _ 18.0 mm; p _ 0.016) but not for the measurement from the bifurcation to the radial tunnel (median difference _ 7.0 mm; p _ 0.396). In conclusion, the location of the radial nerve bifurcation is subject to both intra- and inter-individual variations. Its specific relationship to the lateral humeral epicondyle also varies, occurring both distal and proximal to the level of the epicondyle. Clinical implications of these findings warrant further investigation.
Saturation in qualitative research: exploring its conceptualization and operationalization
(2017-09-14) Saunders, Benjamin; Sim, Julius; Kingstone, Tom; Baker, Shula; Waterfield, Jackie; Bartlam, Bernadette; Burroughs, Heather; Jinks, Clare
Saturation has attained widespread acceptance as a methodological principle in qualitative research. It is commonly taken to indicate that, on the basis of the data that have been collected or analysed hitherto, further data collection and/or analysis are unnecessary. However, there appears to be uncertainty as to how saturation should be conceptualized, and inconsistencies in its use. In this paper, we look to clarify the nature, purposes and uses of saturation, and in doing so add to theoretical debate on the role of saturation across different methodologies. We identify four distinct approaches to saturation, which differ in terms of the extent to which an inductive or a deductive logic is adopted, and the relative emphasis on data collection, data analysis, and theorizing. We explore the purposes saturation might serve in relation to these different approaches, and the implications for how and when saturation will be sought. In examining these issues, we highlight the uncertain logic underlying saturation - as essentially a predictive statement about the unobserved based on the observed, a judgement that, we argue, results in equivocation, and may in part explain the confusion surrounding its use. We conclude that saturation should be operationalized in a way that is consistent with the research question(s), and the theoretical position and analytic framework adopted, but also that there should be some limit to its scope, so as not to risk saturation losing its coherence and potency if its conceptualization and uses are stretched too widely.
The sample size debate: Response to Norman Blaikie
(Informa UK Limited, 2018-03-27) Sim, Julius; Saunders, Benjamin; Waterfield, Jackie; Kingstone, Tom
In his detailed response to our paper on sample size in qualitative research, Norman Blaikie raises important issues concerning conceptual definitions and taxonomy. In particular, he points out the problems associated with a loose, generic application of adjectives such as 'qualitative' or 'inductive'. We endorse this concern, though we suggest that in some specific contexts a broad categorization may be more appropriate than a more nuanced distinction - provided that it is clear in which sense the terms are employed. However, other concepts, such as saturation, do not lend themselves to generic use, and require a more detailed conceptualization. Blaikie's analysis also makes it clear that meaningful discussion of sample size in qualitative research cannot occur with reference to an undifferentiated conception of the nature of qualitative research; clear distinctions need to be made within this approach in terms of methodology, ontological and epistemological assumptions and broader research paradigms.