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NAEP Weighting Procedures → 2003 Weighting Procedures and Variance Estimation → Computation of Base Weights

NAEP Technical DocumentationComputation of Base Weights

			School Base Weights for Originally Selected Schools School Base Weights for New Schools School Base Weights for Substitute Schools Student Base Weights

Every sampled school and student received a base weight equal to the reciprocal of its probability of selection. Base weights can vary because selection probabilities can vary. For example, in most states larger schools have a higher chance of selection than smaller schools; and consequently, selected smaller schools in these states have larger base weights than the selected larger schools. Computation of a school base weight varies by whether the school was an originally selected school (i.e., not a new or substitute school), a new school, or a substitute school.

Computation of a student base weight reflects its overall probability of selection accounting for school and student sampling and its assignment to the mathematics or reading assessment.

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