Vanderbilt University released a new study last week that deflates one of the trendiest ideas in education reform: performance pay. After a three-year experiment in the Nashville school district, in which teachers were eligible for up to $15,000 in extra pay if their students scored well on tests, researchers found no impact on academic achievement. Is this bad news for the Seattle School District, which just signed a much-ballyhooed teachers' contract that doles out extra pay to teachers based partly on their performance? Under the new contract, teachers are eligible for "stipends" of $2,500 to $5,200 a year if they get high "student growth ratings," which measure the two-year average of their students' test scores. They also have to earn high marks on evaluations of their teaching style, preparation, and so forth. In order to qualify for the stipend, teachers also have to aid their peers by becoming a "demonstration," "mentor," or "master" teacher. District spokesperson Patti Spencer-Watkins did not immediately know the exact requirements of each role. But she insists that as a consequence of this requirement, the district's performance-pay scheme is critically different from the one studied by Vanderbilt. Here, teachers are supposed to be helping other teachers, and that—theoretically, at least—could help students in ways that merit pay alone would not.