Abstract
Thirty-five states and more than 400 districts offer incentives to teachers who are certified as "accomplished" by the National Board for Professional Teaching Standards. However, the board's criteria for assessing teachers are not universally accepted and may conflict with criteria important to local authorities. The board relies on a very slender evidentiary basis for assessments. It is unable to authenticate or verify the accuracy of the materials it receives. The secrecy surrounding the board's assessments means teachers who fail do not know the reasons why. The involvement of teacher unions in the board constrains the uses to which board assessments can be put. These issues raise the question of whether it is cost-effective to rely on the board to identify accomplished teachers rather than improve local efforts.