NAEP Technical DocumentationComputation of Full-Sample Weights for the 2011 Assessment

Computation of Base Weights

School and Student Nonresponse Weight Adjustments

School and Student Weight Trimming Adjustments

Student Raking Adjustment

The full-sample or final student weight is the sampling weight used to derive NAEP student estimates of population and subpopulation characteristics for a specified grade (4, 8, or 12) and assessment subject (reading, mathematics, science, and writing [WCBA]). The full-sample student weight reflects the number of students that the sampled student represents in the population for purposes of estimation. The summation of the final student weights over a particular student group provides an estimate of the total number of students in that group within the population.

The full-sample weight, which is used to produce survey estimates, is distinct from a replicate weight that is used to estimate variances of survey estimates. The full-sample weight is assigned to participating students and reflects the student base weight after the application of the various weighting adjustments. The full-sample weight for student k from school s in stratum j (FSTUWGT_jsk) can be expressed as follows:

FSTUWGT subscript j s k equals STU underscore BWT subscript j s k times SCH underscore NRAF subscript j s times STU underscore NRAF subscript j s k times SCH underscore TRIM subscript j s times STU underscore TRIM subscript j s k times STU underscore RAKE subscript j s k

where

STU_BWT_jsk is the student base weight;
SCH_NRAF_js is the school-level nonresponse adjustment factor;
STU_NRAF_jsk is the student-level nonresponse adjustment factor;
SCH_TRIM_js is the school-level weight trimming adjustment factor;
STU_TRIM_jsk is the student-level weight trimming adjustment factor; and
STU_RAKE_jsk is the student-level raking adjustment factor.

School sampling strata for a given assessment varies by school type and grade. See the links below for descriptions of the school strata for the various assessments.

Last updated 24 September 2014 (JS)

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