Definition: The Judgement Sampling is the non-random sampling technique wherein the choice of sample items depends exclusively on the investigator’s knowledge and professional judgment.
In other words, the investigator chooses only those sample items which he feels to be the best representative of the population with regard to the attributes or characteristics under investigation. The judgement sampling is not a scientific method as the sample items are selected on a judgement basis and hence the results could be affected by the personal prejudice or bias of the investigator.
Thus, the judgement sampling involves the risk that the conclusion drawn could be influenced by the preconceived notions of the investigator about the elements under study. Even though the principles of sampling do not apply to the judgement sampling, it can be used for solving several economic or business problems, such as:
- In case the sample size is small, the judgement sampling certainly includes all the important elements that might be missed by the simple random sampling.
- In the case of day-to-day business problems or public-policy creation, the executives and the government officials are pressed for time and therefore could not wait for the probability sample designs. Thus, the judgement sampling is the only practical method that can be used to take the actions immediately on the basis of estimates that are readily available with the businessmen and public officials.
- It can be used to conduct the pilot studies. Since the reliability of sample results depends on the practical knowledge or the expertise of an individual and if it is good and skillfully applied then the judgment sampling will yield valuable results.
Thus, the success of this method depends on the excellence in judgment. If the person is knowledgeable about the population and has a good judgment ability, then the sample selected will be typical of the population with regard to the attributes or characteristics. On the other hand, the skewed results are obtained if the selection suffers from the personal prejudice or bias of the investigator.