In each final student nonresponse adjustment cell c for a given sample, the student nonresponse adjustment factor STU_NRAFc was computed as follows:
Sc is the set of all eligible sampled students in cell c for a given sample,
Rc is the set of all assessed students within Sc,
STU_BWTck is the student base weight for a given student k,
SCH_TRIMk is the school-level weight trimming adjustment factor for the school associated with student k,
SCH_NRAFk is the school-level nonresponse adjustment factor for the school associated with student k, and
SUBJFACk 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.