In this paper, a part of the Evaluating and Improving Teacher Preparation Programs Project, commissioned by The National Academy of Education, the authors examine a set of performance- and outcomes-based measures that have emerged in the past few decades as potential ways to assess teacher preparation program (TPP) effectiveness and to support program improvement. Both the historical review of accreditation and more contemporaneous review of performance- and outcomes-based measures inform recommendations for how TPP accreditors might more effectively incentivize, support, and provide assurance of teacher preparedness and effectiveness. The authors suggest that TPPs reorient data use toward professional quality assurance and continuous improvement; partner with states to build system capacity to support accreditation and program approval; and provide leadership in key efforts to update standards and structures for the teaching profession.