Key Concepts about Identifying Correct Sampling Weights and File Locations
NHANES sample weights are a measure of the number of people in the US population represented by a sampled study participant. Sample weights are constructed for each 2-year survey cycle and account for the unequal probability of selection, non-response adjustment, and adjustment to independent population controls. Weights for data collected by interview, which include physical activity questionnaire responses, can be found in the demographic file (DEMO) for each survey cycle.
For more information about weighting, see the Weighting module in the Continuous NHANES Web Tutorial.