Approximately one-third of American freshmen at two-year and four-year colleges require remedial coursework and over 40 percent of employers rate new hires with a high school diploma as "deficient" in their overall preparation for entry-level jobs. Yet, over the past decade, as these students marched through America's public education…

This addendum to previously published results presents alternative analyses of data from large-scale effectiveness studies of Cognitive Tutor Algebra I in middle schools and high schools. These alternative analyses produce results that are substantively the same as previously reported. We find a significant positive effect of 0.21 standard…