coverage errormeans the error that stems from not covering part of the population in the sampling frame (‘under coverage’) or, on the contrary, from keeping some ineligible units in the sampling frame (‘over coverage’).
eligible unitsmeans the set of units selected from the sampling frame that are part of the statistical population;
gross samplemeans the set of units initially selected from the sampling frame, comprising the eligible units (the net sample and the non-response units) as well as the ineligible units;
ineligible unitsmeans the set of units selected from the sampling frame that are not part of the statistical population;
net samplemeans the set of eligible units (including substitution units), from which enough information has been obtained to include the unit in the survey estimations;
non-responsemeans the failure of a survey to collect any data from a unit designated for data collection, or for one or several data items in the survey questionnaire, or for both, specifically:
sampling errormeans part of the difference between a population value and an estimate of that value derived from a random sample, arising from the fact that only a subset of the population is enumerated;