Quota sampling method is a non-probability sampling and it can be defined as “a sampling method of gathering representative data from a group”. Quota sampling means to take a very tailored sample that’s in proportion to some characteristic or trait of a population chosen by the researcher. The population is divided into groups and samples are taken from each group to meet a quota. Care is taken to maintain the correct proportions representative of the population. In short, quota sampling is a non-probabilistic version of stratified sampling.
With probability sampling, like simple random sampling, there are rules that govern how to get the sample. However, with quota sampling, no formal rules exist. The general steps to follow are:
- Dividing the population into specific groups.
These should be exclusive. For example, you might divide the population into five groups according to their cultural background like that:
- Asian (India)
- Asian (China)
- Black (African)
- Calculating a quota for each group.
This is to figure out the proportion of subgroups to the population and choosing the sample size. You may confirm that each of the cultural group occupies 1/5 of the population, therefore in order to achieve research objectives, 30 representatives from each group and the total sample size of 150 respondents would be appropriate.
- Determine specific condition(s) to be met and quota in each group
Both genders, males and females need to be represented equally in your sample group. This is a specific condition that has to be satisfied. Accordingly, you recruit 15 males and 15 females from each group.
Application of quota sampling ensures that sample group represents certain characteristics of the population chosen by the researcher. In example above, an equal representation of both genders, males and has been chosen as an important characteristic of sampling.
Quota sampling is useful when time is limited, a sampling frame is not available, the research budget is very tight or when detailed accuracy is not important.
- Quota sampling emerges as an attractive choice when you are pressed for time, since primary data collection can be done in shorter time with this method compared to many alternatives. The application of quota sampling can save costs and time
- Quota sampling is not dependent on the presence of the sampling frames. In occasions where suitable sampling frame is absent, quota sampling may be the only appropriate choice available. Under quota sampling, Subsets are chosen and then either convenience or judgment sampling is used to choose people from each subset. The researcher decides how many of each category is selected.