The Mathematics Learning Study committee offers a promising mechanism for helping those concerned with school mathematics begin to use the available research more productively. The committee of practitioners, research mathematicians, cognitive psychologists, researchers in mathematics education, and a representative from the business community was convened by the National Research Council to synthesize the research on preK-8 mathematics learning to provide recommendations for best practice in the early years of schooling. Committee members applied the criteria of relevance, soundness, and generalizability in examining the evidence on mathematics learning and looked for a body of evidence that converged on a single point and that made good common and theoretical sense among the research studies that met those criteria for a given topic. A consensus had to be reached on the studies that would be cited in the draft report and the language that would be used to describe them. The entire draft was then reviewed by 15 independent reviewers.