In a short essay, list and discuss the four commonly used nonprobability sampling techniques used in marketing research

What will be an ideal response?

a. Convenience sampling attempts to obtain a sample of elements based on the convenience of the researcher. The selection of sampling units is left primarily to the interviewer. Often, respondents are selected because they happen to be in the right place at the right time. Examples of convenience sampling are 1. use of students, church groups, and members of social organizations, 2. mall intercept interviews conducted without qualifying the respondent, 3 . department stores using charge account lists, 4. tear-out questionnaires included in magazines, 5. "people on the street" interviews, and 6. Internet browsers.
b. Judgmental sampling is a form of convenience sampling in which the population elements are selected based on the researcher's judgment. The researcher chooses the sampling elements because she or he believes they represent the population of interest. Common examples of judgmental sampling include 1. test markets selected to determine the potential of a new product, 2. purchase engineers selected in industrial marketing research because they are considered to be representative of the company, 3 . bellwether precincts selected in voting behavior research, 4. expert witnesses used in court, and 5. department stores selected to test a new merchandising display system.
c. Quota sampling introduces two stages to the judgmental sampling process. The first stage consists of developing control categories, or quotas, of population elements. Once the quotas have been assigned, the second stage of the sampling process takes place. Elements are selected using a convenience or judgment process. There is considerable freedom in selecting the elements to be included in the sample.
d. In snowball sampling, an initial group of respondents is selected, usually at random. After being interviewed, these respondents are asked to identify others who belong to the target population of interest. This process is continued, resulting in a snowball effect as one referral is obtained from another. Thus, the referral process effectively produces the sampling from which respondents are selected.