sample design, unit nonresponse, multilevel analysis
Response rates of face-to-face surveys often show regional variation. In larger cities e.g., response typically will be lower than in smaller villages. Following current survey practices, substitution of survey non-respondents is no longer recommended. In order to achieve an adequate regional representation of the population in a survey, differential regional oversampling can be an option. We show how regional ineligible rates and response rates of previous surveys can be used in a multilevel analysis to obtain residuals that form the basis for the computation of an ineligible correction and a regional oversampling factor for subsequent surveys. We argue that this oversampling design is a good alternative or complement to nonresponse weighting. We illustrate our approach with the sampling procedure used for the last edition of the yearly survey on social and cultural changes in the Flemish region.