Absence of Conflict of Interest

The studies Dynarski et. al. (2007) and Campuzano et. al. (2009), cited in the references section below, were prepared, in whole or in part, by staff of Mathematica Policy Research, Inc. (MPR). However, because the Cognitive Tutor ^® Algebra I study samples fell outside the scope of the review, the studies were not eligible for review under the Middle School Math topic area.