January 2012

Addition through Subtraction: Are Rising Test Scores in Connecticut School Districts Related to the Exclusion of Students with Disabilities?

Robert Cotto, Jr., Ed.M.

This report finds that the exclusion of thousands of students with disabilities from reported Connecticut Mastery Test results has distorted reported trends in test scores. Following test scores from year to year in the same grade, the study finds that statewide improvements in standard Connecticut Mastery Test (CMT) scores reported by the Connecticut State Department of Education (SDE) between 2008 and 2009 -- the period of the largest reported gains -- were largely the result of the exclusion of students with disabilities from these standard test results, rather than overall improvements in performance. For example, 84% of the reported improvement in 4th grade math proficiency between 2008 and 2009 and 69% of the improvement in 8th grade reading proficiency could be attributed to the exclusion of these students. Much of the reported improvements in later years could also be attributed to this exclusion, though there were some modest overall gains as well.

In 2009, state and federal policy changes enabled school districts to offer a modified assessment (MAS) to students with disabilities that the districts determined would not have passed the CMT in math and/or reading. As a result of these policy changes, the share of students taking the regular CMT declined substantially. Prior to 2009, students who did not reach the proficient level on the CMT because of their disabilities were included in statewide CMT results. In 2009, thousands of low-scoring students were assigned to take the MAS test instead of the standard CMT, and these students were not included in the CMT results. Thus, CMT scores reported by the State Department of Education appeared to improve in large part because these low-scoring students were no longer included in the calculations.

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