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NAEP Weighting Procedures → 2002 Weighting Procedures and Variance Estimation → State Assessment Weights → Calculation of Replicate Weights for the 2002 State Assessment → Computing Student-Level Replicate Base Weights for the 2002 State Assessment → Replicate Variance Estimation for Certainty Schools → Replicate Strata for Sampled Students in Certainty Schools

NAEP Technical DocumentationReplicate Strata for Sampled Students in Certainty Schools

The primary strata for student replicate weighting factor assignments were generated by subject (reading or writing) and school.

Within the primary strata, the sampled students were paired off into preliminary replicate strata. Within each primary stratum with an even number of sampled students, all of the preliminary replicate strata were doublets, and within primary strata with an odd number of sampled noncertainty schools, one of the replicate strata was a triplet (the last one), and all others were doublets. For a description of the differences in assignment of replicate weights between doublets and triplets, see Replicate Variance Estimation.

If there were more than 62 preliminary replicate strata for a jurisdiction, the preliminary replicate strata were then grouped to form 62 replicate strata. This grouping was done to maximize the distance in the sort order between grouped preliminary replicate strata. The first 62 preliminary replicate strata for example were assigned to 62 different final replicate strata in order (1 through 62), with the next 62 preliminary replicate strata then assigned to final replicate strata 1 through 62, so that for example the 1st preliminary replicate stratum, the 63rd preliminary replicate stratum, the 125th preliminary replicate stratum (if there were that many), etc. were all assigned to the first final replicate stratum. 

If, on the other hand, there were fewer than 62 preliminary replicate strata for a jurisdiction, the number of final replicate strata was equal to the number of preliminary replicate strata. The remaining replicate weights for the jurisdiction were set equal to the school base weight (so that those replicates contribute zero to any replicate sum of squares).

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