For many, merit, defined by test scores, is a readily accessible representation of academic ability, and both the K-12 and postsecondary systems have used such scores as a guide at multiple levels of decision making and accountability. In assessing the strengths and limitations of increasingly test-defined efforts to improve K-12 education and, ultimately, to expand diversity on college campuses through such a purely merit-based system, this article seeks to lay out key considerations that ought to be examined. Acknowledging that many confounding influences, including housing and school segregation, resource inequities, support services, and social factors outside the walls of the school impact those who ultimately flow through the pipeline to the college admission process, this article also focuses on how testing influences that pipeline.