dures were handled in the same way as in the early 1990s, and students with special needs could be excluded from the assessment. For the S2 sample, revisions aimed at increasing participation were made to the criteria given to schools for determining whether to include students with special needs, but no accommodations or adaptations were offered. For state NAEP, the schools were split between S1 and S2. For national NAEP, a third sample of schools, S3, was identified, in which the revised inclusion criteria were used, and accommodations were permitted for students with disabilities and English language learners. These students were allowed to participate with the accommodations that they routinely received in their state or district testing.

Analyses of the 1996 data revealed no differences in inclusion rates between the S1 and S2 samples, so the S1 criteria were discontinued, and further research was based on samples of schools that applied either the revised criteria. Comparison of the S2 and S3 samples provided the opportunity to examine the net effects of both types of changes, both more lenient criteria for inclusion and the use of accommodations.

The research continued with the 1998 national and state NAEP reading assessment and the 2000 assessments (math and science at the national level in grades 4, 8, and 12 and at the state level in grades 4 and 8; reading at the national level in grade 4). Analyses of the 1998 and 2000 data revealed that providing accommodations did increase the number of students with disabilities and English language learners included in NAEP in grades 4 and 8.

Table 3-1 presents information from the research study on the participation rates of students with disabilities and English language learners in NAEP’s reading and math assessments for fourth graders. Participation rates (column 6) were calculated by dividing the number of students assessed (column 5) by the number identified (column 4) and multiplying by 100. Thus, the table shows that the percentages of students with disabilities who participated in NAEP’s fourth grade reading assessment were 13.8 percent in 1992 and 34.1 percent in 1994. These were years in which students with disabilities and English language learners could participate but no accommodations were allowed. Participation rates for the S2 (accommodations not allowed) and S3 (accommodations allowed) study samples are displayed separately for each of the years the study was in place.

Comparisons of the participation rates in a given year demonstrate the impact of providing accommodations. For example, for the 1998 fourth grade reading assessment, the participation rate for students with disabilities was 6.3 percentage points higher for the S3 sample than for the S2 sample. The median differences over assessment years between the participation rates when accommodations were not allowed and were allowed were 17.7 percent for students with disabilities and 21.3 percent for English language learners.

Table 3-2 presents this same information from the research study on the participation rates of students with disabilities and English language learners in NAEP’s reading and math assessments for eighth graders. For eighth graders, the