quota control
in survey methodology, an approach that imposes a limit on the number of respondents that are obtained either in the total sample or in substantively meaningful subgroups, such as those defined by gender or ethnicity. The approach is efficient because it does not overuse resources, such as respondent time or good will, by obtaining more individuals than are needed for a study. It also allows a researcher to obtain a desired balance of sample sizes across groups for statistical testing. Most computerized surveys include an automatic quota control function.