Qualitative research sample size determination has always been a contentious and confusing issue. Studies are often vague when explaining the processes and justifications that have been used to determine sample size and strategy. Some provide no mention of sampling at all, whilst others rely too heavily on the concept of saturation for determining…

Recruiting participants through gatekeepers has been widely discussed in qualitative research. However, when a sampling frame is not available, surveying through gatekeepers can also be important for quantitative studies. We used three sampling methods to survey guardians of University students: (a) a gatekeeper variant of the time-space sampling,…

This research note discusses opportunities and challenges of using online survey engines for social network analysis (SNA) data collection and assessing sample size and representativeness. The discussion is based on a case study of SNA data collection for a pilot research on health-relevant policy networks in Canada. Our approach demonstrates how…

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…

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…

Snowball sampling is frequently advocated and employed by qualitative social researchers. Under certain circumstances, however, it is prone to faltering and even failure. Drawing on two research projects where the snowball failed to roll, the paper identifies reasons for this stasis. It goes on to argue that there are alternative forms of…

In the field of social sciences, certain tasks, such as the identification of typologies and the characterization of groups of individuals according to a set of questions, tend to pose a challenge for researchers. Further complications arise if the chosen rating scale is from 0 to 10, since the responses can be treated either as metric or…

Ragin's Qualitative Comparative Analysis (QCA) is often used with small to medium samples where the researcher has good case knowledge. Employing it to analyse large survey datasets, without in-depth case knowledge, raises new challenges. We present ways of addressing these challenges. We first report a single QCA result from a configurational…

This brief paper introduces a new approach to assessing the trustworthiness of research comparisons when expressed numerically. The 'number needed to disturb' a research finding would be the number of counterfactual values that can be added to the smallest arm of any comparison before the difference or 'effect' size disappears, minus the number of…

Snowball sampling is generally seen as a highly effective sampling technique that allows for the study of difficult to reach or 'hidden' populations. It is also seen as a valuable tool for the study of particularly sensitive or private matters. As a result, it was chosen as the sampling method for a research study into illegal drug users over the…