Measures of quality are now in widespread use across states as part of quality improvement initiatives. For example, many states are currently using global measures of quality that were first developed for research and practice purposes (such as the Environmental Rating Scales) in their Quality Rating Systems (QRSs). Although global quality measures are widely used and applied in both the research and policy arenas, recent analyses indicate that the associations between global measures of quality and child outcomes are modest. Findings suggest that existing measures of quality may not capture adequately those aspects of practice and children's experiences that are linked most closely to children's development. Indeed, measures of specific practices are found to be slightly better predictors of child outcomes than are global quality measures. The goal of this research brief is to explore areas for refining, extending, and developing measures of quality for early childhood education and school-age care settings. The authors focus on identifying the practices and aspects of the environment that support specific domains of children's school readiness (language and literacy; math, science, and general cognitive development; social emotional development; and health, safety, and nutrition), as well as two specific contexts of development (families and culture). It is of critical importance that, as new measures are developed, adequate attention is paid to their applicability across settings, age groups, and diverse demographic backgrounds. Specifically, measures must be developmentally appropriate and applicable among children with special needs, such as children with disabilities or children with limited English proficiency. Where possible, they highlight aspects of quality within domains that accommodate variations of setting, age, race/ethnicity, ability, and linguistic and cultural diversity. (Contains 18 footnotes.)