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NAEP Weighting Procedures → 2002 Weighting Procedures and Variance Estimation → National Main Assessment Weights → Computation of Base Weights → School Base Weights for Substitute Schools

NAEP Technical DocumentationSchool Base Weights for Substitute Schools

A school that takes the place of a nonresponding originally selected school is known as a substitute school. A substitute school is treated as if it were the original school that it replaced, and so it is assigned the school base weight of the original school.

For recruited cooperating substitutes of nonresponding originally sampled schools, a substitute adjustment factor was attached as a weighting factor to the base weight in later calculations. (It is the factor SUBADJ in school nonresponse adjustment factors.) This factor is designed to allow the student sample from the participating substitute school to fully represent the nonresponding originally sampled school. It is equal to the ratio of the estimated grade enrollment for the originally sampled school to the estimated grade enrollment for the substitute school. The student sample from the substitute school then "represents" the grade-eligible group from the originally sampled school. For example, suppose the originally sampled school had 50 grade-eligible students, with the substitute school having 60 students. In this case the substitute adjustment factor would be 50/60. The 60 students' assessments would be "representing" the 50 students from the originally sampled school. Note that the substitute selection process was designed to minimize the differences between the originally sampled school enrollment and the substitute school's enrollment.

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