To address concerns about low graduation rates and a lack of workforce readiness, states and districts have been experimenting with different models of high school reform. One of the most popular models has been the Early College High School (ECHS) model, small schools that blur the line between high school and college. Since 2002, over 200 ECHSs have been created under the auspices of the Early College High School Initiative, which is primarily funded by the Bill & Melinda Gates Foundation. North Carolina has the largest concentration, with over 70 ECHSs across the state. The purpose of this study is to rigorously examine the implementation and impact of the Early College High School model in North Carolina. This study is the first to utilize a longitudinal experimental design to assess the impact of the ECHS model on student outcomes. The study has three main goals: (1) Determine the impact of the model on selected student outcomes; (2) Determine the extent to which impacts differ by student characteristics; and (3) Examine the implementation of the model by site and the extent to which variation in specific model components is associated with impacts. Nineteen ECHS in North Carolina are participating in the study. Early results from this study show that the Early College High School model is having a positive impact on many outcomes associated with remaining in school and becoming ready for college. These results suggest that the ECHS is making substantial progress towards its goal of graduating more students who are ready for college and work. Although these findings are very positive, they are restricted to the model as implemented in North Carolina. Other early colleges around the country may not follow the same design principles and may not receive the same level of assistance in implementation as the schools in North Carolina; as a result, their results may differ. (Contains 1 figure and 4 tables.)