Judgmental sampling which may also be referred to as authoritative sampling is a non-probability sampling technique in which the researcher collects units for sampling based on his own existing knowledge or professional judgement .Non-probability sampling involves gathering samples in a process that does not give all individuals in the population equal chances to be selected (Fleetwood, 2020). Judgmental sampling method is majorly in cases where knowledge of the authority is able to select a more representative sample, which in turn may yield more accurate data than if other sampling techniques were used. It is most effective when only a limited number of individuals possess the trait that the researcher is interested in. Unlike a random sample data obtained from judgmental samples ay not be extrapolated to the entire population.
Judgmental sampling is appropriate in situations where there is a restricted number of people in the population who have qualities that the researcher expects from the target population. The advantages of this sampling technique include, consumes minimal time for execution, allows the researcher to approach their target directly and it yields almost real time results (Fleetwood, 2020). One of its weaknesses is in evaluating the reliability of the of the authority or expert, hence in order to avoid error it is advisable to choose the best and most experienced authority in the field of interest. The sampling process may also be biased since no randomization is used, which may lead to misinterpretation of entire population which makes it difficult to make generalization of the study results.
The term response rate is mostly used in survey research to refer the number of people who completed a survey divided by the number of people in the sample. It is a mathematical formula used by survey researchers as a tool to understand the degree of success in obtaining completed interviews in a sample (Lavrakas, 2008). it is often expressed in terms of a percentage. The term may also be used in marketing to refer to the number of people that responded to an offer. Response rates can only be calculated with a defined sample group. This means that one needs a constant number of people that are being approached to take the survey. Deployment methods like pop-up and embed make it difficult to define the number of people who are represented in the survey which can render the measurement of a response rate unreliable
A low response rate may give rise to sampling bias if the nonresponses is equal among the participants regarding outcome and or exposure. It is referred to as nonresponse bias. A survey response rate is an indicator of the quality of a survey. Higher response rate assures obtaining of more accurate survey results. Higher response rate is often preferred because the missing data is not random and there is no satisfactory statistical solution to deal with missing data that may not be random. In bid to eliminate nonresponse bias, it is important that a pretest of the survey is first done and later to recognize and resolve any issues as they happen.
Fleetwood, D. (2020). Judgmental Sampling: Definition, Examples and Advantages | QuestionPro. Retrieved 18 May 2020, from https://www.questionpro.com/blog/judgmental-sampling/
Lavrakas, P. (2008). Response Rates. Retrieved 18 May 2020, from https://methods.sagepub.com/reference/encyclopedia-of-survey-research-methods/n490.xml