[Sampling plan for the National Survey Sexual Behavior and Perceptions of the Brazilian Population concerning HIV/AIDS, 2005].

OBJECTIVE To describe the sampling plan and estimation methods used to collect and analyze data in the survey Sexual Behavior and Perceptions of the Brazilian Population concerning HIV/AIDS in 2005. METHODS The study presents the decisions that were made concerning population definition, strata of interest to the survey and to the sampling plan, main procedures for data analysis and sample performance in the field. SAMPLING RESULTS A probabilistic plan was designed with 5,040 sampling units obtained from the Brazilian population, with individuals aged between 16 and 65 years living in large Brazilian urban centers. It is a complex sampling plan distributed over eight main estimation domains, designed in multiple stages. A man or a woman was interviewed in the last stage. Each interviewed unit and each household have specific probability of belonging to the sample.