What’s Purposive Sampling?
A form of non-probability sampling in which decisions concerning the individuals to be included in the sample are taken by the researcher.
Features
Some types of research design necessitate researchers taking a decision about the individual participants who would be most likely to contribute appropriate data, both in terms of relevance and depth
For example...In life history research, some potential participants may be willing to be interviewed
A case study design is another type of research that often requires a purposive sample.
Procedure
Proceeds on the belief that the researcher knows enough about the population and its element to handpick the sample
selects “typical” persons
selects widest variety
Types of Purposive sampling
There are a wide range of purposive sampling techniques that you can use. Each of these types of purposive sampling technique is discussed in turn:
Maximum variation sampling
is a search for variation in perspectives that used to capture a wide range of perspectives relating to the thing that you are interested in studying. This can often help the researcher to identify common themes that are evident across the sample.
Homogeneous sampling
is the opposite of maximum variation sampling. A homogeneous sample is often chosen when the research question that is being address is specific to the characteristics of the particular group of interest, which is subsequently examined in detail.
Typical case sampling
used when you are interested in the normality/typicality of the units you are interested, Typical means that the researcher has the ability to compare the findings from a study using typical case sampling with other similar samples
Extreme (or deviant) case sampling
used to focus on cases that are special or unusual, typically in the sense that the cases highlight notable outcomes, failures or successes.
Critical case sampling
is particularly useful in exploratory qualitative research, research with limited resources, as well as research where a single case (or small number of cases) can be decisive in explaining the phenomenon of interest.
Total population sampling
is a type of purposive sampling technique where you choose to examine the entire population. (i.e., the total population) that have a particular set of characteristics (e.g., specific experience, knowledge, skills, exposure to an event, etc.)
Expert sampling
used when your research needs to glean knowledge from individuals that have particular expertise. This expertise may be required during the exploratory phase of qualitative research, highlighting potential new areas of interest or opening doors to other participants.