Principals (N = 76) in a large western U.S. school district were randomly assigned to be evaluated using either a new standards-based system or to continue with the old system. It was hypothesized that principals evaluated with the new system would report clearer performance expectations, better feedback, greater fairness and system satisfaction, and spending more effort on priorities emphasized in the new system. Surveys and interviews were used to assess these perceptions. The hypotheses about feedback and satisfaction were supported. The study also revealed several issues with implementing standards-based evaluation, including competition with many other messages that define performance expectations for principals.