A method of sampling whereby a specified number of interviews is required for different sub-groups. For example:
- 50 males under 30
- 50 females under 30
- 50 males 30 or above
- 50 females 30 or above
The key distinction between quota sampling and stratified random sampling is that in stratified sampling people are randomly selected to participate in the research and then it is determined whether the are eligible according to whether the quotas are or are not full. By contrast, in quota sampling people satisfying the description of each group are searched for in the most cost-effective way.
Quota sampling is the primary means of recruiting samples for qualitative research and is conducted from time-to-time in modern quantitative surveys. The term quota sampling is generally used as a pejorative term in survey research as when a sample has been obtained in this way there is no scientific basis for drawing any conclusions about the population from the survey (i.e., as quota sampling is not a form of probability sampling).