In the last fifteen years dramatic changes have occurred in early childhood education, particularly in early literacy. Responding to the research, public libraries have transformed their services to young children and caregivers. In 2004, the Public Library Association launched Every Child Ready to Read. Maryland librarians were on the forefront of this effort, which developed in tandem with their It's Never Too Early campaign. At the same time, libraries have been trying to develop outcome measures to assess their impact on users. The current study uses data from a kindergarten readiness assessment in literacy and finds a positive correlation with children's library use as shown by circulation and attendance at children's programs in Maryland. This paper examines the implications of such research on policies and practices and makes recommendations for future study. (author abstract)