NAEP Technical DocumentationCalculation of Replicate Weights for the 2002 State Assessment

Defining Replicate Strata and Forming Replicates

Computing School-Level Replicate Weights

Computing School Replicate Nonresponse Adjustments

Computing Student-Level Replicate Base Weights

Computing Student-Level Replicate Nonresponse Adjustments

Trimming Student-Level Replicate Weights

Poststratification of Replicate Student Weights

In addition to the regular weights, a set of replicate weights was provided for each student. These replicate weights are used in calculating the sampling variance of estimates obtained from the data, using the jackknife repeated replication method. These weights were aimed at reflecting the features of the sample design appropriately in each jurisdiction, so that when the jackknife variance estimation procedure is implemented, approximately unbiased estimates of sampling variance are obtained. This page gives the specifics for generating the replicate weights for the 2002 State NAEP assessment samples. The theory that underlies the jackknife variance estimators used in NAEP assessments is discussed on the web page Replicate Variance Estimation.

In each sample, replicates were formed in two steps. First, each school was assigned to one or more of 62 replicate strata. In the next step, a random subset of schools (or, in some cases, students within schools) in each replicate stratum was excluded. The remaining subset and all schools in the other replicate strata then constituted one of the 62 replicates.

The computation of replicate weights includes

defining replicate strata and forming replicates;
computing school-level replicate base weights;
generating school-level replicate nonresponse adjustments;
computing student-level replicate base weights;
generating student-level replicate nonresponse adjustments; and
computing student-level poststratification adjustments.

Last updated 18 December 2008 (RF)

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