This is an important methodological question in research. It does not seem to me that because the study is exploratory it can be restricted to one case. One of the pillars of research is generalizability; one cannot generalize one's findings from one case even if it is an in-depth investigation. And even if one is not after generalizing, it is safe to deal with a representative sample from each group to be able to find a guiding pattern justifying the thesis behind the raison d'etre of the study.

Following answers.

I appreciate my fellow RGrs up-to-date on this methodological question. And while I am hoping in my study to produce some insights that will contribute to my, and others understanding of the issue, I am not striving for generalizable results from this study. Also, Ahmed, while I appreciate the link, the guidance in it seems to be less evidence-based and more authority driven. As those of us who regularly use qualitative methodology come to know, even doing one case study can be intense, so limiting the number to a manageable number is necessary. Key question remains: how few is enough? Thanks for your thoughts!

For PhD study on gamers which is a qualitative exploratory study, I had a minimum of 11 subjects for interviewing, gameplay observation and recording. For a subsequent book chapter I published from my PhD study, I included 4 of the participants as empirical evidence for conceptualization of the theoretical model and coding scheme.

Thanks, Toh, for your contribution. How did you decide on the selection of the 4 from the original 11, and was that sufficient for your purposes or did you find it perhaps too many?

I had 11 participants played 5 different games and those 4 played Bioshock. For the purposes of refining the model and developing the coding scheme, 4 participants would be sufficient. If you would like a copy of my article, I can send you If you provide me an email.

Perhaps you might elaborate a bit, Toh, in this RG discussion on how you thought the 4 participants you selected "would be sufficient." That type of reasoning would contribute to our conversation regarding the methodological question I have raised. Could it be that the 4 in a cumulative manner, for example, represented most if not all of the diversity of your total sample?

Why do I have 4 participants:

1. I require my participants to have completed the entire game and gone through all stages of the study including the interviews. Those participants who have not completed the study would not form the core source of my data. These 4 completed the entire study.

2. I don't have a representative sample. The participants were recruited via snowball sampling where initial participants recruited via advertisements introduced their friends.

There is a related thread here discussing about sample size for qualitative study:

https://www.researchgate.net/post/I_am_going_to_interview_students_as_a_case_study_How_many_participants_should_be_interview_in_the_Qualitative_research

It is mentioned that the number of participants depend on the concept of "saturation" where we stop recruiting participants when we have induced the data that are required for the research questions.

Thank you, Toh, for your elaboration. Agree with you that a prerequisite for case study selection would be completion of the entire study. In your situation, sounds like that was 4 out of your total sample of 11. In my situation, I have a total sample of approximately 40, and 36 completed the entire study. So, for sheer feasibility issues, I cannot write up 36 indepth case studies. My problem is that I, and other qualitative researchers who face similar circumstances, need some additional rationale for how many to select to report as case studies.

Other RGers' thoughts welcome to join this conversation!

In terms of case study analysis, 40 participants is too many. Case study is done to highlight the anomaly in a given area of research or highlight a significant aspect of a case that can be impacted to an area. I think would assess your 36 cases and look for those that present anomaly, uniqueness, and significance -- perhaps three or four and this becomes a strong case study sample size.

Darrin, sorry if what I shared earlier in a response confused the issue. I was NOT saying I have nearly 40 case study participants in my study.(I have N=36 that completed it). From that total sample of approximately 40, what is being discussed is how many case study participants would be advisable to select from each of two groups that make up that sample--one group perceives the innovation is beneficial and a second group does not. I know at least one case study selected from each group is necessary, but are more? And if so, for what reason(s)? Your suggestion of selecting those that may "present anomaly, uniqueness, and significance" is promising, but how does one know if any would be "significant" or adequately "unique?" "Anomalous" ones would be the easiest to identify, but I believe in this instance, other researchers would also be interested in cases of the most common individuals in each group, as well. Thanks to all who are engaged in this discussion!

I would suggest the question of why? Why do individuals believe a particular way? Then consider answers for their level of deviation from common answers among your participants. For the many "typical" or similar answers create an aggregate case example. This takes into account both issues. You could also use demographic information collected from your participants, for example age. Choose any outlier ages to do case examples with. Perhaps most of the participants are married then aggregate the married into a single case example and do another related to the few people that are not married? These of course are just examples of ways I might consider the data to discover uniqueness.

Darrin, I appreciate very much your thoughtful consideration of this methodological issue in qualitative research (case study selection and number). Thank you.

Diving deeply into the participants' reasons for "why" they hold their beliefs regarding the pedagogical innovation I am investigating the crafting of aggregate cases that portray commonalities of each group makes much sense to me. I will identify participants in each of the two groups who held similar/common views/beliefs then present a rich aggregate case for them in which an individual case enacted such views/beliefs. I then will search through my data again looking for instances in which my participants in each of my two groups expressed differing, even outlier views/beliefs, and select from that information a second case study to present for each group to represent the diversity within each group. I expect one result of this methodological decision will be a narrative structure for the story I will report which will be potentially engaging to its readers.

What say you, RGers to this proposed direction for me to take in my study? Advice, caveats welcome!