quota sampling
a method of forming a sample in which a prespecified number of individuals with certain background characteristics, such as a particular age, race, ethnicity, sex, or education, are selected for inclusion. Often, participants are recruited as they arrive; once the quota for a given demographic group is filled, the researcher stops recruiting subjects from that group. A researcher who uses this approach can obtain a final study sample that has the same proportional characteristics as the target population, enabling statistical testing to be performed on a subset of cases that is appropriately representative of the larger group of interest. See deliberate sampling. See also quota control.