Research Findings: Examining the effects of professional development of the early childhood workforce that fit within the constraints of government policy is crucial for identifying types and amounts of effective training and informing child care policy. The present study used a cluster-randomized trial to evaluate the effects of a professional development program for child care providers designed to meet the criteria for 2 state-level policies: (a) that child care providers working in licensed centers engage in 10 hr of professional development annually and (b) that all licensed child care settings provide 30 min of developmentally appropriate literacy activity daily. Results indicated that 10 hr of professional development focused on literacy was effective for significantly improving the literacy practices and knowledge of child care providers. However, it was not effective in eliciting substantial growth in child literacy outcomes, at least in the short term. The lack of child outcomes illustrates the importance of measuring professional development effects at both the provider and child levels. Practice or Policy: This study illustrates the importance of critically questioning and analyzing state policy, particularly dosage. In practice, dosage is an influential factor in how professional development is selected by programs and providers, because most policies only specify a required number of hours to be completed. The design of policy, which can influence both provider practice and child outcomes, relies upon alignment between early childhood research and policy.