The SURVEYREG Procedure

Stratum Information

When you specify the LIST option in the STRATA statement, PROC SURVEYREG displays a Stratum Information table, which provides the following information for each stratum:

  • Stratum Index, which is a sequential stratum identification number

  • STRATA variable(s), which lists the levels of STRATA variables for the stratum

  • Population Total, if you specify the TOTAL= option

  • Sampling Rate, if you specify the TOTAL= option or the RATE= option. If you specify the TOTAL= option, the sampling rate is based on the number of nonmissing observations in the stratum.

  • N Obs, which is the number of observations

  • number of Clusters, if you specify a CLUSTER statement

  • Collapsed, which has the value 'Yes' if the stratum is collapsed with another stratum before analysis

If PROC SURVEYREG collapses strata, the Stratum Information table also displays stratum information for the new, collapsed stratum. The new stratum has a Stratum Index of 0 and is labeled 'Pooled.'