The environment of U.S. schools has changed dramatically over a quarter century as standards tied to test-based accountability and market competition became commonplace. We examine the issues that school systems face in this changing environment, to identify considerations for researchers interested in reform as educational system building. We highlight a central dilemma: Systems manage environmental pressures to become more coherent enterprises that focus on tested outcomes while managing the inherited differentiated organizations and environmental pressures which support these enterprises. We identify four activity domains that are defined by these competing pressure: consensus on outcomes; infrastructure to connect outcomes with instruction; recruitment that is aligned with outcomes; and competing environmental pressures.