In this Issue Brief, differences in the average number of course credits earned between high school graduates and dropouts, both within and accumulated across academic years, are examined in order to describe enrollment and completion behavior of high school graduates and dropouts. Differences in course credit accrual by selected subjects (English, mathematics, and science) are also reported. Data for this study are drawn from high school transcripts collected in 2005 as part of the first follow-up to the National Center for Education Statistics (NCES) Education Longitudinal Study of 2002 (ELS:2002). These high school transcripts provide enrollment histories, graduation dates, and coursetaking patterns. The findings from the analysis indicate that high school dropouts earn fewer credits than do on-time graduates within each academic year, and the gap in course credits accrued between dropouts and on-time graduates increased across academic years. Differences were also observed in the course credit accrual of dropouts and on-time graduates by selected subjects (e.g., mathematics, science, and English). In addition, the gap in the cumulative number of course credits accrued between on-time graduates and dropouts grew more pronounced over time, and the disparity in cumulative course credits was most evident in the final academic year in which they earned any course credits. (Contains 2 tables, 1 figure, and 7 endnotes.)