In recent years, there has been a tremendous proliferation of quantitative evaluative social measures in the field of law as well as society generally. One of these measures, the U.S. News & World Report rankings of law schools, has become an almost obsessive concern of the law school community, generating a great deal of speculation about the effects of these rankings on legal education. However, there has been no attempt to systematically ascertain what, if any, effects these rankings have on the decisionmaking of students and schools in the admission process. This article documents some of these effects by conceptualizing rankings as a signal of law school quality, investigating (1) whether students and schools use this signal to make decisions about where to apply and whom to admit, and (2) whether the creation of this signal distorts the phenomenon—law school quality—that it purports to measure. Using data for U.S. law schools from 1996 to 2003, we find that schools' rankings have significant effects on both the decisions of prospective students and the decisions schools make in the admissions process. In addition, we present evidence that the rankings can become a self-fulfilling prophecy for some schools, as the effects of rank described above alter the profile of their student bodies, affecting their future rank. Cumulatively, these findings suggest that the rankings help create rather than simply reflect differences among law schools through the magnification of the small, and statistically random, distinctions produced by the measurement apparatus.