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Internal Quality Control Checks

The sampling and weighting staff perform the following quality control checks during the various weighting stages for NAEP:

  • reviewing the computer code used to calculate and assign weights in order to check implementation of weighting specifications;
  • checking input file and variable names, and output files and variable names;
  • checking the SAS logs for missing values and other warnings when SAS programs are used for implementation;
  • reviewing a sample of records to verify weight calculations and/or assignments;
  • comparing the weighted sample counts and/or totals with the corresponding frame counts and other control totals, or estimates from the previous weighting stage, whenever available;
  • calculating and checking descriptive statistics of the weights, including
    • a listing of extreme weights,
    • the sum of the weights,
    • the number of cases with missing weights,
    • percentiles of the weight distribution, and
    • average weights within selected and relevant student groups; and
  • checking any other statistics that could be used to confirm expected patterns.

NAEP sampling and weighting staff have developed SAS macros for use in weighting for complex sample surveys. These macros perform such tasks as cell-weighting adjustments for nonresponse, poststratification (not used in state assessment), raking, creation of replicates for variance estimation, and weighting adjustments (i.e., nonresponse adjustment, poststratification, and raking) of the replicate weights.

Last updated 22 May 2008 (DB)

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National Center for Education Statistics -
U.S. Department of Education