Research conducted in the United States and Canada on the effects of group care outside of family settings for 20 or more hours per week on a regular basis shows few differences between day care and home reared children on four major variables: attachment, social interactions, cognitive development, and physical health. Of nine studies of attachment, only one found significant negative effects for day care children and two replications of the design of this study did not confirm its results. In the area of social interaction, day care children were found to be less interested in strange adults but more socially active with familiar peers than were the home reared children. Infant and toddler day care generally facilitated cognitive development especially for lower working class children. In regard to the health of children, the consensus of physicians associated with day care programs is that there are no serious medical consequences of day care if the center maintains adequate space, sanitation, staff, and medical supervision. Research aimed at investigating the effects of day care has been global, directed primarily at the identification of differences between the two groups, and the children studied were attending primarily University-affiliated programs. It seems time to move on to more refined hypotheses which reflect the range of children, families, programs, and developmental phenomena available in day care settings. (JMB)