This report builds upon a series of National Center for Education Statistics (NCES) reports on high school dropout and completion rates that began in 1988. It presents estimates of rates in 2012, provides data about trends in dropout and completion rates over the last four decades (1972-2012), and examines the characteristics of high school dropouts and high school completers in 2012. Four rates are presented to provide a broad picture of high school dropouts and completers in the United States, including the event dropout rate, the status dropout rate, the status completion rate, and the adjusted cohort graduation rate. Each rate contributes unique information. Information about individuals who pass the GED exam is provided to place the different rates into context relative to this widely used alternative high school credential. The appendices also include information on the averaged freshman graduation rate. The following are appended: (1) Technical Notes; (2) Glossary; and (3) Standard Error Tables.