Low graduation rates of high school students are a problem for the Native American community. One possible solution for low graduation rates is a credit recovery program that may assist Native American students to recover credit not earned in their early high school years. The purpose of this study was to examine the effectiveness of a credit recovery program on graduation rates of at-risk students in a high school on the Navajo Indian Reservation. The research question posed in the time-lagged comparative design was to determine the impact of a credit recovery program on at-risk students by comparing two years of graduation rates for at-risk students and graduation rates from the two prior years, when a credit recovery program was not available. Two methods used to assist the students in the program followed the theoretical foundation of the proximal development theory. The first was assisted performance, which was designed to increase the students' zone of proximal development thereby increasing the students' ability to complete credits. The second was providing multiple credit recovery methods so the students could select the method closest to their learning style. Independent t-test analyses of graduation data showed that the credit recovery program did not result in higher graduation rates, and use of assisted performance and multiple methods of credit recovery did not affect the results. The current study contributes to social change by empirically documenting problems in the effectiveness of existing intervention models aimed at increasing graduation rates when applied in Native American schools. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]