A Closer Look at Exclusion and Accommodations as Related to Assessment ResultsWithin any assessment year, exclusion and accommodation rates may vary across jurisdictions. In addition, exclusion and accommodation rates may increase or decrease between assessment administrations, making it difficult to interpret comparisons over time within jurisdictions. Since students with disabilities (SD) and English language learners (ELL) tend to score below average on assessments, exclusion of students from these groups may result in a higher average score than if those students had taken the assessment. Providing appropriate testing accommodations (e.g., providing extended time for some SD or ELL students to take the assessment), on the other hand, removes barriers that would otherwise prevent them from demonstrating their knowledge and skills. NCES has commissioned several studies of the impact of exclusion and accommodation rates on overall scores. NCES has also investigated scenarios for estimating what the average scores might have been if excluded students had been assessed. The data in the sections below are presented as an exploration of how accommodations and exclusion rates may impact assessment results for jurisdictions that participated in the 2007 NAEP assessments. Population Subset EstimatesOne way to investigate the potential impact of accommodation rates is to examine the results for the subset of the population that was not given testing accommodations. Students who were not accommodated include students who may or may not have been identified as SD and/or ELL. Another way to examine the potential effect of accommodation rates is to view performance data for only those students who were not identified as SD and/or ELL. Comparing the results reported for all assessed students to those for nonaccommodated or non-SD/ELL students provides some indication of the impact of the accommodations. The tables below provide such estimates for the urban districts that participated in the 2007 Trial Urban District Assessments in mathematics, reading, and writing. In the mathematics and reading assessments where previous assessments were administered in 2005, the trends in performance were the same in most districts for all students, for nonaccommodated students, and for non-SD/ELL students. This suggests that provision of accommodations did not affect the mathematics or reading trends for these districts. Full Population EstimatesSeveral statistical scenarios have been proposed, based on different assumptions about how excluded students might have performed. Combined with the actual performance of students who were assessed, these scenarios produce results for the full population (that is, one that includes estimates for excluded students) in each jurisdiction and each assessment year. These techniques provide an indication as to which statements about trend gains or losses might be changed if exclusion rates were zero in both assessment years (and if the assumptions about the performance of missing students are correct). The results of one of these scenarios are presented here. However, the methods used to construct the scenario are still under development. The results of this special analysis should not be interpreted as official results. The Trial Urban District Assessment (TUDA) results are presented in the following tables. The first column of each of these tables presents the reported score gain (or loss) for each jurisdiction based on the sample of students who were included in the assessment. The second column shows the score gain (or loss) under the full population scenario. The third column reports the difference between the official gain and the gain under this scenario. Statistically significant score changes in columns one and two are marked with an asterisk. A footnote marks jurisdictions that show a trend that is statistically significant in the official results but not significant under the full population scenario or vice versa. The state results are presented in the following tables: Read more about the NAEP inclusion policy, including the percentages of students excluded from recent assessments. See full population estimates for the 2005 mathematics, reading, and science assessments, and read more details about the method used to compute the full population estimates.
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