The SURVEYMEANS Procedure

Overview

The SURVEYMEANS procedure produces estimates of survey population means and totals from sample survey data. The procedure also produces variance estimates, confidence limits, and other descriptive statistics. When computing these estimates, the procedure takes into account the sample design used to select the survey sample. The sample design can be a complex survey sample design with stratification, clustering, and unequal weighting. PROC SURVEYMEANS uses the Taylor expansion method to estimate sampling errors of estimators based on complex sample designs. This method obtains a linear approximation for the estimator and then uses the variance estimate for this approximation to estimate the variance of the estimate itself (Woodruff 1971, Fuller 1975). When there are clusters, or primary sampling units (PSUs), in the sample design, the procedure estimates variance from the variation among PSU. When the design is stratified, the procedure pools stratum variance estimates to compute the overall variance estimate.

PROC SURVEYMEANS uses the Output Delivery System (ODS) to place results in output data sets. This is a departure from older SAS procedures that provide OUTPUT statements for similar functionality.

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