Abstract
A number of authors have investigated the impact of early childhood education and care programs on the development of children. Often they have focused on the effects on children from socio-economically disadvantaged families. To assess the effects of various preschool programs on cognitive development, recent key studies were reviewed. In addition, the extent to which these programs could establish equal educational opportunities for children from different social backgrounds was evaluated. Program start, intensity, and duration were considered. The findings indicate that the vast majority of recent early education and care programs had considerable positive short-term effects and somewhat smaller long-term effects on cognitive development and that in relative terms children from socio-economically disadvantaged families made as much or slightly more progress than their more advantaged peers. Despite this, early childhood education and care cannot compensate completely for developmental deficits due to unfavorable learning conditions in disadvantaged milieus. Implications for research and policy are discussed.