Convenience sampling is a type of nonprobability sampling in which people are sampled simply because they are "convenient" sources of data for researchers. In probability sampling, each element in the population has a known nonzero chance of being selected through the use of a random selection procedure. Nonprobability sampling does not involve known nonzero probabilities of selection. Rather, subjective methods are used to decide which elements should be included in the sample. In nonprobability sampling, the population may not be well denned. Nonprobability sampling is often divided into three categories: purposive sampling, convenience sampling, and quota sampling.

Convenience sampling differs from purposive sampling in that expert judgment is not used to select a representative sample of elements. Rather, the primary [Page 149]selection criterion relates to the ...