Within-Unit Selection

In survey research, a sample of households usually must be converted into a sample of individuals. This often is accomplished by choosing respondents within households using methods intended to yield a sample similar to the population of interest. Ideally, this is done with a probability technique because all unit members will have a known, nonzero chance of selection, thus allowing generalization to a population. Probability methods, however, tend to be time consuming and relatively intrusive because they ask about household composition, potentially alienating prospective respondents and therefore increasing nonresponse.

Most researchers have limited resources, so often they need quicker, easier, and less expensive quasi-probability or nonprobability methods that they believe will yield samples adequately resembling the population being studied. Although surveyors wish to minimize nonresponse and ...