Definition: The Quota Sampling is yet another non-probability sampling method wherein the population is divided into a mutually exclusive, sub-groups from which the sample items are selected on the basis of a given proportion.
Simply, Quota Sampling is a form of judgment sampling technique wherein the investigator selects the sample items from the exclusive sub-groups on the basis of his knowledge and professional judgment. In this method, first of all, the quotas, i.e. a proportion in which the sample items are to be selected is set up and then within the quotas the choice of sample items depends exclusively on the investigator’s judgment.
For Example, Suppose an interviewer is told to interview 250 people living in certain geographical areas. Out of which 100 males, 100 females and 50 children are to be interviewed. Within these quotas, the interviewer can select any person on the basis of his personal judgment.
The quota sampling is both economical and less time-consuming, but however there is a chance of personal prejudice or bias of the investigator that can adversely affect the credibility of the results. Such as, if the interviewer finds children insufficient to answer the questions, then he might ask their mothers to give answers on their behalf. Thus, this may tamper the results, and the purpose of research gets unfulfilled.