The study represented an examination of the factors influencing students' ability to successfully graduate from postsecondary institutions and whether this differs between high school equivalency credential earners and high school diploma earners. The study has clarified a predictive relationship among type of high school credential and graduation success and entrance examination score and graduation success. An interaction between entrance examination score and type of high school credential was also present. With the disparity in graduation outcomes between high school equivalency credential earners and high school diploma-earning students, understanding student and institutional factors influencing or preventing success in getting a postsecondary degree is necessary to reduce the gap in educational success. The study was conducted using a sample of 1000 students from archival student data from a vocational, postsecondary institution in Los Angeles, California. The data generated in this quantitative study were analyzed using ANOVA and multinomial regression. Statistically significant, predictive relationships among the variables high school credential, entrance examination score, and graduation success were identified, as well as the interaction between high school credential and entrance examination score. The predictive relationship between type of high school credential and graduation success indicated students with high school equivalency credentials graduated at a higher rate from vocational postsecondary programs than students with traditional high school diplomas. Recommendations include the development of career preparatory courses or testing to encourage students to understand the types of programs that are most suitable for the future outcome they are seeking. Creating programming for students that facilitates understanding the required investment of time and financial resources and the potential return on education in terms of paying back any financial resources they have borrowed or expended. Other recommendations include institutions reinforce the benefits to students of any services that support graduation success and the development of relationships with employers and the community that promote placement of graduates. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]