註釋 The changing nature of the U.S. economy has fostered concerns that too few students are successfully completing postsecondary education (Achieve, 2004). Three quarters of those who enter high school graduate within four years, with approximately 70 percent of those graduates enrolling immediately in some form of postsecondary education (Ross et al., 2012). Of those who do attend, insufficient numbers complete a degree with only a little less than half (49 %) of beginning postsecondary students attaining some sort of a postsecondary credential within six years of enrolling (Ross, et al., 2012). As a result, there have been numerous initiatives to increase the number of students who graduate from high school prepared to enroll and progress in postsecondary education. One approach is the Early College High School (ECHS or early college) model, small schools that blur the line between high school and college. The primary goal of the early college model is to increase the number of students who graduate from high school and who continue on to and succeed in college. This paper presents results from a longitudinal experimental study that is examining the impact of early colleges on students' outcomes in high school and in postsecondary (PS) education, specifically on postsecondary enrollment and college credit accrual during and after high school. Early results from this study show that the Early College High School model is increasing students' enrollment in postsecondary education, primarily by the required exposure in high school. The results show that, as is inherent in its design, the program is successful in providing early access to college. This paper also reports results from a detailed cost and benefit analysis of the early college model. The following are appended: (1) References; and (2) Tables and Figures. 