In this essay David Labaree explores the historical and sociological elements that have made educational researchers dependent on statistics. He shows that educational research as a domain, with its focus on a radically soft and thoroughly applied form of knowledge and with its low academic standing, fits the pattern in which weak professions have been most likely to adopt quantification. One problem with educational researchers' seduction by the quantitative turn is that it deflects attention away from many of the most important issues in the field, which are not easily reduced to standardized quanta. Another is that by adopting this rationalized, quantified, abstracted, statist, and reductionist vision of education, educational policymakers risk imposing reforms that will destroy the local practical knowledge that makes the ecology of the classroom function effectively. Quantification, Labaree suggests, may be useful for the professional interests of educational researchers, but it can be devastating for school and society.