Qual 1
Participants are chosen because they met certain criteria, or possess certain characteristics or traits.
Purposive - Qual
Cases that demonstrate a particular theory particularly well, or allow you to develop a theory are chosen
Theoretical - Qual
Where every member of the population has an equal probability of being selected
Random - Quant
The sample aims to achieve the full range of experiences, demographics and so on to capture the full range of the subject being explored
Maximum - Qual
You choose cases that are unique, or special in some way
Extreme Case Sampling - Qual
Where groups are randomly selected, rather than individuals.
Cluster Sampling - Quant
Your sample is chosen on the basis that they are ‘typical’ of a particular context, for example
Typical Case Sampling - Qual
Initial participants are identified, and these participants identify further potential participants themselves
Snowball - Qual
The population is divided into subgroups. Random samples are then taken from within these groups
Stratified - Quant
The sample is chosen as it is convenient in terms of location, accessibility and so on
Convenience Sampling - Qual
You select samples as they arise, taking advantage of unexpected opportunities
This method involves selecting every nth case, for example taking every fourth name from a list.
Systematic Sampling - Quant
Individuals are chosen on the basis of specific knowledge that they possess
Key informant Sampling - Qual
Name two ways in which mistakes can be made in selecting a sample.
1. Convenient individuals - already known to the research may cultivate bias
2. Mixture of volunteer and random - no mentioning of difference
3. Using a random sample when other sampling methods would be more preferrable
4. Not having the appropriate sample size
How can sample sizes be determined?
1. Quant: Sample size calculator, previous studies
2. Qual: Design determined - Aiming for transferability of rich data and potentially saturation