In every NAEP survey, the student sample consists of the following groups:
The withdrawn students are students who have left the school before the assessment data. Excluded students are those students who cannot be assessed even with an accommodation because they are students with disabilities (SD) or are limited-English-proficient students (LEP). Assessed students are either assessed in the initial session, or if they were absent for that session perhaps in the makeup session. The last category includes students who were not excluded (i.e., “were to be assessed”), but were not assessed, due to either absence from both sessions or a refusal to participate. Assessed students are also classified as assessed without an accommodation or assessed with an accommodation. The latter group can be divided into SD students assessed with an accommodation or LEP students assessed with an accommodation (students neither SD nor LEP can only be assessed without an accommodation). Note that some SD and LEP students are assessed without accommodations.