What Is A Good Sample Size For Qualitative Research

Sample Size: What is an appropriate sample for qualitative studies?

Interviews are a commonly used information collection method in qualitative studies, where the goal is to sympathise or explore a phenomenon. They're an extremely effective fashion to gather rich, descriptive information about people'south experiences in a program or exhibition, which is one reason we use them often in our work at RK&A. Figuring out sample size for interviews can sometimes feel trickier than for quantitative methods, like questionnaires considering there aren't tools like sample size calculators to utilize. Notwithstanding, there are several important questions to consider that tin help guide your determination-making (and while you practise so, remember that a cornerstone of qualitative research is that it requires a high tolerance for ambivalence and instinct!):

How much does your population vary? The more than homogenous the population, the smaller the sample size. For example, is your population all teachers? Do they all teach the same grade level? If so, you tin employ a smaller sample size, since the population and related phenomenon are narrow. Generally speaking, if a population is very homogeneous and the phenomenon narrow, aim for a sample size of around 10. If the population is varied or the miracle is complex, aim for around 40 to l. And if you want to compare populations, aim for 25 to thirty per segment. In any case, a sample of more than 100 is by and large excessive.
What is the scope of the question or phenomenon y'all are exploring? The more narrow the question being explored or phenomena being studied, the smaller your sample size tin can be. Are you looking at one program, or only i aspect of a program? Or, are you comparing programs or looking at many different aspects of a programme?
At what point will you accomplish redundancy? This is cardinal for determining sample size for whatsoever qualitative data collection method. You want to sample merely to the signal of saturation—that is, end sampling when no new information emerges. Another way to recall about this is that you stop collecting data when yous keep hearing the same things once again and once again. To be clear, I'1000 talking about big trends here—while each interview volition have its own nuance and the small details might vary from interview to interview, you can end when the larger trends start to echo themselves and no new trends arise.

The question of "how many" for qualitative studies might e'er feel a bit frustrating, since (as illustrated by the questions in a higher place) the respond will always exist "it depends." But remember, as the word "qualitative" suggests, information technology's less about verbal numbers and more well-nigh agreement the quality of responses, including the latitude, depth, and range of responses. Each study volition vary, but as long as you consider the questions above the next time y'all are deciding on sample size for qualitative methods, yous tin can exist confident you're approaching the study in a systematic and rigorous manner.