The Obama administration is using billions of dollars in federal stimulus grants to encourage schools to offer merit pay to teachers. A growing body of research on teacher effectiveness has put new emphasis on the importance of recruiting and retaining strong teachers. But questions remain about the effect of merit pay on teachers? motivation and student achievement. Teachers unions often object to plans to use standardized test scores in evaluating teachers and determining pay. Still, some teachers unions have worked with districts to develop merit pay plans. The Los Angeles Unified School District plans to experiment with merit pay and a coalition of charter school organizations in Los Angeles is working on its own merit pay experiment with funding from the Bill and Melinda Gates Foundation. One way to overcome opposition may be to make sure teachers who are rewarded are helping their entire schools and not just the children in their classroom.