Sampling weights, which are also known as survey weights, are positive values associated with the units in your sample. Ideally, the weight of a sampling unit should be the “frequency” that the sampling unit represents in the target population.

Often, sampling weights are the reciprocals of the selection probabilities for the sampling units. When you use PROC SURVEYSELECT, the procedure generates the sampling weight component for each stage of the design, and you can multiply these sampling weight components to obtain the final sampling weights. Sometimes, sampling weights also include nonresponse adjustments, poststratification, or regression adjustments by using supplemental information.

When the sampling units have unequal weights, you must provide the weights to the survey analysis procedures. If you do not specify sampling weights, the procedures use equal weights in the analyses.