Family is important for child development. Internationally it is well documented that family environments of young children are important predictors of outcomes later in life, such as education, labor market participation, earnings, health, and crime. In particular, children of families with low income and education, and children of broken families, have substantially lower prospects for success in life than other children. Norway is no exception.This research project will investigate how Norwegian publ ic policies targeted towards early childhood can improve children's long-run outcomes and increase social mobility. Recent research from a number of fields suggests that early childhood is a particularly promising time to intervene in the lives of childre n, especially those from disadvantaged families. Three different sub-projects will investigate the following questions:1. What is the role of the universal childcare system in Norway for children's long-run development and social mobility? To what exten t does childcare quality, such as staff-child ratio, matter for child development?2. How important is family income in early childhood for children's long-run development in Norway? Will children benefit from public programs that increase early childhoo d family income? In particular, do such programs increase social mobility in Norway?3. How important is the presence of two parents for children's long-run development? Will public policies restricting a parent's post divorce relocation be beneficial to the child?The project will investigate these questions using individual level register data for the whole resident Norwegian population available every year back to the late 1960s. The empirical analyses will utilize a wide range of child outcomes measu red far into the child's adulthood. Moreover, the analyses will focus on establishing causal inferences, using various instrumental variable and difference-in-difference approaches.