af2a44c6_l__Variance_Estimation__Task_3_SUDAAN_proc_descript_procedure_Explanation
[Statements] proc descript span> data =BP_analysis_Data design =WR noprint DEFT2 ATLEVEL1=1 ATLEVEL2=2 ; [Explanation] 
Use proc descript to specify the dataset (BP_analysis_Data), specify the sample design using the design option WR (with replacement). Use the noprint option to suppress printing of results. In this example, you will be sending the results to a SAS data file for further calculations and printing in SAS. Use a DEFT2 statement to request the calculation of the design effect using method 2 (see SUDAAN manual for details on the differing methods for calculating design effect). Method 2 is the method recommended by NCHS for NHANES data. The ATLEVEL1=1 and ATLEVEL2=2 options specify the sampling stages (in NHANES, the number of strata is level 1, and the number of PSUs is level 2) for which you want counts per table cell. ATLEV1 is the number of strata with at least one valid observation and ATLEV2 is the number of PSUs with at least one valid observation. These numbers are used to calculate degrees of freedom.
Continuous NHANES Web Tutorial: Variance Estimation: Task 3
Explanation