Recently, I have attended a training where the instructor said 36 is the recommended sample size of case study in qualitative techniques. I am curious to know if the total population is less than 36 then how it could be?
I was unsure what form you research was taking. I continued to interview people until I reached data saturation. I don't think there can be a recommended number just selected in this way.
This is maybe of interest to you; a similar question was asked in 2012 and continued to be responded to:
I don't think you can specify the sample size in terms of the number of participants; rather most important is that the stage of your data collection meet the data saturation, that's it. I am writing a paper on this debate, if you have an interesting paper, please send me it.
In my opinion from the literature I have recently gone through, there is no minimum specification when it comes to case studies. However, a researcher must determine, based on the peculiarity of the case study what 'number' or kind of sample to select. It is important to understand that handling too large a sample in a case study may become problematic.