In September 2003, the Head Start Bureau, in the Department of Health and Human Services (HHS) Administration for Children and Families (ACF), implemented the National Reporting System (NRS), the first nationwide skills test of over 400,000 4- and 5-year-old children. The NRS is intended to provide information on how well Head Start grantees are helping children progress. Given the importance of the NRS, this report examines:(1) what information the NRS is designed to provide; (2) how the Head Start Bureau has responded to concerns raised by grantees and experts during the first year of implementation; and (3) whether the NRS provides the Head Start Bureau with quality information. Government Accountability Office (GAO) recommends the HHS Assistant Secretary for ACF, in collaboration with the Head Start Bureau, determine how NRS data will be used for accountability and targeting technical assistance; monitor the effects of the NRS on local Head Start practices:use first year NRS results to conduct further study of the reliability and validity of the NRS; compile a detailed, well-organized document on the technical quality of the NRS; improve management of its data on NRS participation; and study the costs and benefits of sampling in administering the NRS. ACF generally agreed with the recommendations.