Nonsampling Error

Nonsampling error is a catchall phrase that refers to all types of survey error other than the error associated with sampling. This includes error that comes from problems associated with coverage, measurement, nonresponse, and data processing. Thus, non-sampling error encompasses all forms of bias and variance other than that associated with the imprecision (variance) inherent in any survey sample.

Coverage error refers primarily to the bias and variance that may result when the sampling frame (the list from which the sample is drawn) used to represent the population of interest fails to adequately "cover" the population, and the portion that is missed differs in non-ignorable ways from the portion that is included on the frame. Coverage error also includes bias and variance that can result when ...