NAEP Assessment Weighting Procedures → Weighting Procedures for the 2008 Assessment → Weighting Procedures for the 2008 LTT Assessment → Computation of Full-Sample Weights for the 2008 LTT Assessment → School and Student Nonresponse Adjustments for the 2008 LTT Assessment → Student Nonresponse Adjustment for the 2008 LTT Assessment → Student Nonresponse Adjustment Factor Calculation for the 2008 LTT Assessment

NAEP Technical DocumentationStudent Nonresponse Adjustment Factor Calculation for the 2008 LTT Assessment

In each final student nonresponse adjustment cell c for a given sample, the student nonresponse adjustment factor STU_NRAF_c was computed as follows:

where

• S_c is the set of all eligible sampled students in cell c for a given sample,

• R_c is the set of all assessed students within S_c,

• STU_BWT_k is the student base weight for a given student k,

• SCH_TRIM_k  is the school-level weight trimming factor for the school associated with student k,

• SCH_NRAF_k is the school-level nonresponse adjustment factor for the school associated with student k, and

• SUBJFAC_k is the subject factor for a given student k.

The student weight used in the calculation above is the adjusted student base weight, without regard to subject, adjusted for school weight trimming and school nonresponse.

Nonresponse adjustment procedures are not applied to excluded students because they are not required to complete an assessment. In effect, excluded students were placed in a separate nonresponse cell by themselves, considered respondents, and all received an adjustment factor of 1. While excluded students are not included in the analysis of the NAEP scores, weights are provided for excluded students in order to estimate the size of this group and its population characteristics.

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