There are several small-scale randomized controlled trial (RCT) studies in the United States documenting the benefits of curriculum-led experimental preschool programs and "pre-kindergarten" education for long-term educational, occupational and social outcomes for disadvantaged children. In addition a larger-scale quasi-experimental study in Chicago found similar benefits up to age 28 of sustained, publicly-funded early education to subsequent education, socio-economic status, health and crime for a disadvantaged population. Such programs are cost-effective with disadvantaged groups, at risk for poor outcomes, in that the savings outweigh any costs. Besides benefits for disadvantaged groups, there is strong evidence that preschool education, whether or not a specialized program or routine provision, is beneficial for the general population. Studies of population-representative samples in the U.S. find benefits for school readiness of prekindergarten experiences, with greater if preschool started between 2 and 3 years of age. Similar evidence also occurs outside the U.S. and effects are long-term (e.g., preschool prio r to compulsory education at age 5 in a population sample was associated with increased qualifications, employment and earnings up to age 33). In France, preschool (école maternelle) is a universal, free, education program with access from age 3. During the 1960s and 1970s large-scale expansion in France led to the enrollment of 3-year-olds increasing from 35% to 90% and of 4-year-olds from 60% to 100%. Based on state-collected data of representative samples there were sizable and persistent effects indicating that preschool helps children succeed in school and obtain higher wages in the labor market. Preschool also appeared to reduce socioeconomic inequalities as children from less advantaged backgrounds benefitted more than the more advantaged. Likewise in Switzerland the impact of preschool expansion was associated with improved intergenerational educational mobility with children from disadvantaged backgrounds benefiting most. Further evidence comes from the expansion of preschool education for 3 to 6 year olds in Norway during the 1970s, where examining differential implementation of preschool by municipalities and population education and employment data, it was found that preschool participation was associated with strong benefits for later educational and labor market outcomes across the population.