For almost a decade now, outcomes question has been driving reform in teacher education (Cochran-Smith, 2001). Spurred by sharp criticisms that teacher education programs have not been held accountable for results and that there is little evidence that higher education-based teacher preparation is a fiscally sound and effective educational policy, many new efforts to assess and/or enhance the impact of teacher education have emerged. Although these often rest on strikingly different assumptions about what and pupils should know and be able to do and about what the larger purposes of American schooling should be, all of these efforts assume that a defining goal of teacher education is student learning. They also assume that there are certain measures that can be used to assess the degree to which this outcome is or is not being achieved by teachers, K-12 pupils, teacher educators, higher education institutions, alternative programs, local and state policies, and the education profession itself. This editorial provides a brief of in teacher education by outlining several recent efforts to analyze, document, or enhance the impact of collegiate teacher preparation on teaching, learning, and practice. To make the point that current assessment efforts are quite different from one another in form, content, and intention, I have included examples from the following three loosely defined groupings: empirical studies or reviews that assess the effectiveness of teacher education/ teacher certification as a broad educational policy; national initiatives to make teacher preparation more assessment-based and evidence-driven by spearheading and linking local efforts along these lines; and regional efforts to assess the impact on attitudes, learning, and practices of naturally occurring variations among program components, structures, and arrangements to influence local program decisions but also inform larger policy controversies. ASSESSING TEACHER EDUCATION/ TEACHER CERTIFICATION AS EDUCATIONAL POLICIES For some time now, there have been visible and contentious debates about whether or not there is an empirical warrant for collegiate teacher education and/or for state-regulated teacher certification as broad educational policies that add value to teaching quality and pupil learning outcomes. Two important studies have recently added to this debate. Darling-Hammond and Youngs's (2002) review of existing research on highly qualified teachers was written as a direct response to Secretary of Education Rod Paige's report on teaching quality (U.S. Department of Education, 2002). The Darling-Hammond and Youngs article rejects the conclusions of the Secretary's report, claiming that it fails to meet its own standards for the use of scientific research in formulating public policy. The bulk of the Darling-Hammond and Youngs article is a repudiation of Paige's major propositions based on a thorough analysis that takes into account age of the studies included, sample size, research methods, levels of aggregation, and teacher retention. Not surprisingly, Darling-Hammond and Youngs reach conclusions that are diametrically opposed to Paige's. They conclude the secretary's recommendations are not based on scientific evidence; there is evidence that teacher preparation contributes at least as much to effectiveness and retention as do verbal ability and content knowledge; and, although some of them are well designed, alternate entry paths that do not include the core aspects of teacher preparation lead to ineffective who feel underprepared and leave teaching at high rates. Like the Darling-Hammond and Youngs review, Laczko-Kerr and Berliner's (2002) recent study of the impact of certified and under-certified elementary school on pupils' academic achievement also adds fuel to the fiery debate about teacher certification as educational policy. …