The SURVEYSELECT Procedure

The following statements are available in the SURVEYSELECT procedure:

The PROC SURVEYSELECT statement invokes the SURVEYSELECT procedure. Optionally, it identifies input and output data sets. It also specifies the selection method, the sample size, and other sample design parameters. The PROC SURVEYSELECT statement is required.

The SIZE statement identifies the variable that contains the size measures of the sampling units. This statement is required for any probability proportional to size (PPS) selection method unless you specify the PPS option in the SAMPLINGUNIT statement.

The remaining statements are optional. The STRATA statement identifies a variable or set of variables that stratify the input data set. When you specify a STRATA statement, PROC SURVEYSELECT selects samples independently from the strata that are formed by the STRATA variables. The STRATA statement also provides options to allocate the total sample size among the strata.

The SAMPLINGUNIT statement identifies a variable or set of variables that group the input data set observations into sampling units (clusters). Sampling units are nested within strata. When you specify a SAMPLINGUNIT statement, PROC SURVEYSELECT selects clusters instead of individual observations.

The CONTROL statement identifies variables for ordering units within strata. It can be used for systematic and sequential sampling methods. The ID statement identifies variables to copy from the input data set to the output data set of selected units.

The FREQ statement identifies a variable that contains the frequency of occurrence for each observation. The FREQ statement is available only for sample allocation when no sample is selected, which you can request by specifying the ALLOC= and NOSAMPLE options in the STRATA statement.

The rest of this section gives detailed syntax information for the CONTROL, FREQ, ID, SAMPLINGUNIT, SIZE, and STRATA statements in alphabetical order after the description of the PROC SURVEYSELECT statement.