Mathematica's final report on the Chicago Teacher Advancement Program (Chicago TAP) found that the program did not raise student math or reading scores, but it increased teacher retention in some schools. For example, teachers in Chicago TAP schools at the start of the program in fall 2007 were about 20 percent more likely than teachers in comparison schools to be in those same schools three years later (67 percent versus 56 percent retention rate). However, the program did not have an impact on student achievement overall in the four-year rollout period in the Chicago Public Schools (CPS). Although Chicago TAP increased the amount of mentoring, promotion opportunities, and compensation in participating schools relative to non-TAP schools, the program did not fully implement its performance-based pay or value-added components as intended.