Blackwell Reference Online

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Nonrandom sampling, also called “nonprobabilistic” or “nonprobability sampling,” is any sampling method in which the process that determines whether a member of the population is selected for inclusion in the sample is guided by a nonchance or nonrandom process. Such nonrandom processes can include the investigator choosing who to include in the sample, advertising a study to find participants, or other methods of seeking participants in such a way that whoever is approached, recruited, or selected cannot be described by some kind of random mechanism. Nonrandom sampling methods are often perceived as inferior to random sampling methods (→  Sampling, Random ), and it has been said that their frequent use in communication research renders the field a “prescience” rather than a mature science ( Potter et al. 1993 ). Such a condemnation is too harsh, as nonrandom sampling can be an entirely effective and highly practical way of recruiting participants for a research study, and not a requirement for the application of the principles of scientific investigation ( Sparks 1995 ). But the researcher needs to be well aware of the restrictions on the kinds of inferences that can be made when sampling nonrandomly. Namely, population inference is nearly impossible when a study is based on a nonrandom sample, as the sample is very likely to be unrepresentative of the population the investigator ... log in or subscribe to read full text