A report on preschool diversity finds that most children in public preschools attend programs that are economically segregated. Often times these programs are effectively segregated by race as well. Diversity in preschool matters because of peer effects which show that children from low-income backgrounds make larger academic gains when attending schools with higher-income children, effectively lessening the achievement gap. Peer diversity also offers social benefits to higher-income children as well. Giving parents and children the power to choose which school to attend desegregates schools that are traditionally organized to educate only kids in a particular areas or neighborhoods that often lack socio-economic and racial diversity.