Cadernos de Saúde Pública
On-line version ISSN 1678-4464
VASCONCELLOS, Mauricio Teixeira Leite de; SILVA, Pedro Luis do Nascimento and SZWARCWALD, Célia Landmann. Sampling design for the World Health Survey in Brazil. Cad. Saúde Pública [online]. 2005, vol.21, suppl.1, pp. S89-S99. ISSN 1678-4464. http://dx.doi.org/10.1590/S0102-311X2005000700010.
This paper describes the sample design used in the Brazilian application of the World Health Survey. The sample was selected in three stages. First, the census tracts were allocated in six strata defined by their urban/rural situation and population groups of the municipalities (counties). The tracts were selected using probabilities proportional to the respective number of households. In the second stage, households were selected with equiprobability using an inverse sample design to ensure 20 households interviewed per tract. In the last stage, one adult (18 years or older) per household was selected with equiprobability to answer the majority of the questionnaire. Sample weights were based on the inverse of the inclusion probabilities in the sample. To reduce bias in regional estimates, a household weighting calibration procedure was used to reduce sample bias in relation to income, sex, and age group.
Keywords : Survey Methods; Selection Bias; Sampling Studies.