If you are analyzing survey data, do not use PROC LOGISTIC. Weights in PROC LOGISTIC do not replicate observations - they serve as multipliers in the log likelihood. Only the SURVEY procedures (SURVEYFREQ, SURVEYLOGISTIC, etc.) can provide a proper analysis of survey sample data. A variable specified in the WEIGHT statement in other procedures may produce correct parameter estimates, but their variances will not be correct. Special variance estimators are needed in the analysis of survey data and only the SURVEY procedures have these estimators. See the discussion and examples in the PROC SURVEYLOGISTIC documentation.
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