State accountability systems and the federal No Child Left Behind Act have put additional demands on schools and teachers to improve teacher quality and improve student achievement. Many researchers (e.g., Cohen, 1996; Corcoran & Goertz, 1995; Floden, 1997; Newman, King, & Rigdon, 1997) have argued that such improvements will require a substantial increase in the instructional capacity of schools and teachers. One strategy for capacity building is to provide teachers with incentives to improve their performance, knowledge, or skills. The incentive strategy requires the design and implementation of alternative teacher compensation systems that depart from the single salary schedule (Odden, 2000; Odden & Kelley, 2002). Though slow to take hold, the incentive strategy is currently being pursued by several states (Peterson, 2006). Most of these new or proposed plans link pay to combinations of assessments of teacher performance, acquisition of new knowledge and skills, and student test score gains. The Teacher Compensation Group of the Consortium for Policy Research in Education (CPRE) has been studying the design and effectiveness of such systems for nearly a decade. Findings from this research on some of these systems are the focus of this issue of "CPRE Policy Briefs." Appended is: Summary of Research Activities at the Four Sites.