What is a qualitative sample size?

woman holding a book

In qualitative research, the qualitative sample size is the number of subjects in a study. Qualitative research relies on rich and vivid descriptions of people and their words and actions in the environment under study. The qualitative sample size is generally relatively small, ranging from one to 15 people on average. This is different from quantitative research, which is math- and statistical-based research that relies on much larger samples, sometimes as large as 1,000 individuals or more. A quantitative study, for example, might include comprehensive statistics on the survey responses of 1,000 people who were asked about their views on religion, while a qualitative study on the same topic might include interviews with just three people.

The main reason why a qualitative sample size can be very small is that a qualitative research study depends on the ability to obtain rich and detailed data from its subjects. While it may be appropriate, but not necessary, to include some direct quotes and anecdotes from subjects in a quantitative study, these types of details are absolutely essential for qualitative research studies. A qualitative research study, for example, might focus on in-depth interviews with 10 students and two teachers about the reasons why students drop out of a school with a high dropout rate.

Another example of a qualitative study might be longer term and involve following three university students in a teacher education program during their final year of college and the first five years of their teaching careers to see to what degree they have implemented the education methods they were taught in their undergraduate courses. A study like this would require detailed observations of teachers’ classroom behavior and in-depth interviews with them. The result would be a limited rather than a generalized conclusion about the use of teaching methods learned in college and their reasons for using them or not.

See also  What is a Superfluid? (with photo)

There are cases in this type of research where a qualitative sample size of one would be appropriate. A psychology case study, for example, might focus on a client diagnosed with intermittent explosive disorder with whom a physician has worked for a period of time. In this case study, the psychologist could try to help the client improve his anger outbursts and resume a more normal life, experimentally using cognitive strategies and behavioral management techniques. The psychologist working with the client can also act as a qualitative researcher, documenting the interventions and their success, or lack thereof, with that person. Observations of a client and interviews with him or her – and possibly with people intimately involved in the patient’s life – can provide the rich and detailed data needed for qualitative studies.

Leave a Comment