This report is one of a series presenting findings from the National Job Corps Study. The main impact analysis results based on the experimental design are presented in a companion report. The impact analysis report focuses on the average impacts of the program on post-program earnings and other outcomes. The analysis reported here goes beyond simple average impacts in order to provide program operators and others with information about how specific programmatic achievements contribute to observed average impacts. We apply non-experimental statistical methods to estimate the impacts on quarterly earnings during the 48-month period after application for eligible applicants who attain key program milestones, as well as for those who do not achieve those milestones. The specific milestones we examine include completion of a vocational training program and attainment of a GED while enrolled in Job Corps. The results derived from an examination of the achievement of these two milestone address key policy relevant questions because the Workforce Investment Act of 1998 directs Job Corps to focus on the outcomes of graduates, and defines graduation as either completion of a vocational training program or attainment of a GED.