The "The Effects of Accelerated College Credit Programs on Educational Attainment in Rhode Island" study examined participation in accelerated college credit programs dual enrollment, concurrent enrollment, and Advanced Placement courses in Rhode Island high schools to understand their effects on educational attainment in the 2013/14 grade 9 cohort. The state, which has funded and promoted these opportunities for students to earn college credit during high school over the past five years, sought evidence of the programs' effects on participants' high school graduation rates, postsecondary enrollment rates, and enrollment rates in developmental education courses in college. This document presents the following four appendices that accompany the study: (1) About the study; (2) Methods; (3) Supporting analysis; and (4) Other analyses. [For the full report, see ED612887. For the study snapshot, see ED612888.]