With over half the nation's infants and toddlers in regular, non-parental child care, the quality of that care is a priority concern for policymakers. Many studies show that high-quality child care supports the positive social, emotional, and cognitive development of young children. The research summarized in this policy brief identifies factors that tend to predict higher quality within arrangement types--family child care, center care, and relative care--and describes the range of quality found in each type. A list of resources is included. (Contains 36 endnotes.)