An education production function is an application of the economic concept of a production function to the field of education. It relates various inputs affecting a student's learning (schools, families, peers, neighborhoods, etc.) to measured outputs including subsequent labor market success, college attendance, graduation rates, and, most frequently, standardized test scores. The original study that eventually prompted interest in the idea of education production functions was by a sociologist, James S. Coleman. The Coleman Report, published in 1966, concluded that the marginal effect of various school inputs on student achievement was small compared to the impact of families and friends.[34] Later work, by Eric A. Hanushek, Richard Murnane, and other economists introduced the structure of "production" to the consideration of student learning outcomes. Hanushek et al. (2008, 2015) reported a very high correlation between "adjusted growth rate" and "adjusted test scores"