Abstract:
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The Behavioral Risk Factor Surveillance System (BRFSS) is a network of health-related telephone surveys-conducted by all 50 states, DC, and participating US territories. Data users often aggregate BRFSS state samples for national estimates without accounting for state-level sampling, a practice that could introduce bias because the weighted distributions of the state samples do not always adhere to national demographic distributions. We will be examining six methods of reweighting, which are then compared with key health indicator estimates from the National Health Interview Survey (NHIS) using the 2013 data. Although one of the six methods reduces the variance of weights and design effect at the national level, statistically significant differences between aggregated state weights and national weights did not occur in these analyses. Despite the outcomes in the analyses, the new method leads to weighted distributions that more accurately reproduce national demographic characteristics. To the extent that survey outcomes are associated with these demographic characteristics, matching the national distributions will reduce bias in estimates of these outcomes at the national level.
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