Abstract
This study addresses the important yet underexplored question of whether the Common Core State Standards in Mathematics, first introduced in the United States in 2009 and which emphasize critical thinking and problem-solving, as well as the computer-based assessments aligned with the Common Core, have facilitated or hindered learning for students with disabilities. By analysing administrative data from a large county in California, we track mathematics achievement trends before and after the implementation of the Common Core. Our findings show a significant widening of the achievement disparity in mathematics between students with and without disabilities, suggesting that the Common Core and computerized assessments may have disproportionately affected students with disabilities.