The No Child Left Behind Act of 2001 (NCLB) holds states and the districts and schools under their jurisdictions accountable for student performance; and it does so according to standards that considerably exceed the requirements of earlier federal legislation. While student achievement must be the primary indicator of performance under NCLB, statewide accountability systems are also required to incorporate one additional academic indicator. At the secondary level, this must be the high school graduation rate (HSGR). The states outlined their plans for implementing the federally-mandated statewide accountability systems in the Consolidated State Application Accountability Workbooks, which were submitted to the U.S. Department of Education for approval. This report presents the results of an analysis of these Workbooks and focuses specifically on provisions related to the definition and measurement of high school graduation rates under NCLB.