OECD countries, compensation for teachers drives education spending at all education levels. At the college and university level, spending on instruction decreases but still consumes the majority of education expenditures. Since a majority of public education is funded through local taxes in the US, the wealth of a community affects school district funding. Wealthier communities are able to afford to pay more in income and property taxes, while poorer communities cannot, causing inequalities in public education. One notable inequality that arises from differences in funding is the ability of wealthier schools to afford more qualified educators who are more experienced and can improve student test results. Since many European countries finance education primarily through federal taxes, there is less inequality among schools compared to the US as education spending is more uniform. Equal distribution of education resources has the ability to reduce variation in income by creating a more uniform educational system, which can benefit human capital in the long term. Pre-primary education financing Compared to other areas of basic education, globally comparable data on pre-primary education financing remain scarce. While much of existing non-formal and private programmes may not be fully accounted for, it can be deduced from the level of provision that pre-primary financing remains inadequate, especially when considered against expected benefits. Globally, pre-primary education accounts for the lowest proportion of the total public expenditure on education, in spite of the much-documented positive impact of quality early childhood care and education on later learning and other social outcomes. Education production function 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. 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". A large number of successive studies,