The National Assessment of Educational Progress (NAEP), also known as “the Nation?s Report Card,” is the only nationally representative and continuing assessment of students in the United States. Assessments have been conducted periodically since 1969 in a variety of subjects, including mathematics and reading. The National Center for Education Statistics (NCES), a division of the U.S. Department of Education, is responsible for administering NAEP. The National Assessment Governing Board (NAGB), an independent, bipartisan group, is responsible for setting NAEP policy as well as developing the framework and test specifications for the NAEP assessments.

Since 1990, NAEP has provided assessment results for participating states as well as for the nation. State participation was initially voluntary, but under the No Child Left Behind Act, participation is now required of states receiving Title I funds. Compared with national NAEP results, state results have more stakeholders and therefore tend to generate greater interest. The audience for NAEP data is particularly interested in states’ progress over time, as well as in comparisons across states at a given point in time. Additionally, states are interested in comparing their progress on NAEP with their progress as measured on their own state assessments. It is important for NAEP to aggressively investigate any factors that can potentially obscure or bias these comparisons.

One area of concern is the observed variation in the percentage of students excluded from testing due to their disability (SD) or English language learner (ELL) status. Because SD and ELL students tend to perform near the bottom of the achievement distribution, significant fluctuations in their participation can influence state scores disproportionately. Moreover, these variations have occurred despite NAEP’s efforts to standardize the inclusion and accommodation decision process. The motivation for the present study was to obtain more systematic information about how decisions are made at the local school level so as to better understand the causes of the observed variation and to suggest modifications in NAEP procedures that could reduce variation.