Table of Contents  |  Search Technical Documentation  |  References

NAEP Weighting Procedures → 2002 Weighting Procedures and Variance Estimation → National Main Assessment Weights → Calculation of Replicate Weights → Computing Student-Level Replicate Weights

NAEP Technical DocumentationComputing Student-Level Replicate Weights

This section describes the computation of replicate student base weights. The corresponding calculation of student base weights is given in Computation of Student Base Weights. The replicate student base weights differ considerably between certainty and noncertainty schools. For noncertainty schools, school selection is the first stage of selection and replication is based on the noncertainty school strata. The students “inherit” the replicate weights of their parent noncertainty schools. For sampled students in noncertainty schools the replicate base weights are defined as follows (for school s, student k, replicate weight r):

STUWGT_sk(r) =

w_s(r) * SCHSES_s^(A) * SNRADJ_c(r) * SUBADJ_s * TRIM_s * WINSCHL_s * SES_sk^(A) * YRRND_s

where

• w_s(r) is the replicate school base weight (see Computing School-Level Replicate Weights);

• SCHSES_s^(A) is the session weighting factor (see Computation of School Base Weights for Originally Sampled Schools);

• SNRADJ_c(r) is the replicate school nonresponse adjustment (see Computing Replicate School Nonresponse Adjustments);

• SUBADJ_s is a weighting factor for substitute schools (See School Base Weights for Substitute Schools);

• TRIM_s is the school trimming factor (See Trimming of School Base Weights);

• WINSCHL_s is the within-school student sampling interval;

• SES_sk^(A) is the inverse of the probability of student assignment to session A; and

• YRRND_s is a weighting factor for year-round schools (see Computation of Student Base Weights).

The school weighting factors are replaced with replicate weighting factors, but none of the student weighting factors. For students in certainty schools, students are the first stage of selection. In this case, the student weighting factors are replicated to reflect student selection. These replicate factors are given as REPFAC_sk(r). The overall student replicate weight for students in certainty schools is as follows:

STUWGT_sk(r) =

w_s * REPFAC_sk(r) * SCHSES_s^(A) * SNRADJ_c(r) * SUBADJ_s * TRIM_s * WINSCHL_s * SES_sk^(A) * YRRND_s

Note that w_s is not replicated, but the school nonresponse factor is. Certainty schools will have replicate weighting factors that differ from the full-sample weighting factor. Note that almost all absolute certainty schools were in the fourth and eighth grades' public school jurisdiction alpha samples.¹

¹ With the exception of one absolute certainty school in the twelfth-grade private school sample.

Printer-friendly Version