Nonresponse Rates

The nonresponse rate is defined as the percentage of all potentially eligible units (or elements) that do not have responses to—at least a certain proportion of—the items in a survey questionnaire. Thus, a nonresponse rate can be calculated at the unit level (in which all data from a sampled respondent are missing) and/or the item level (in which only data for certain variables from a sampled respondent are missing).

The nonresponse rate is not the same as nonresponse error. Nonresponse error occurs when nonre-spondents in a survey are systematically different from respondents in nonnegligible ways that are germane to the objects of the study. For example, if the survey attempts to assess public opinion on the president's new plan for the Iraq War, then nonresponse error ...