The purpose of this study was to use a comprehensive framework to examine academic, psychosocial, noncognitive, and other background factors that are related to retention at a large, public four-year institution in the southeastern United States. Specifically, the study examined what factors are most important in predicting first-to-second year retention both before the student enrolls at the university and after completion of their first semester of coursework. Data were drawn from institutional records, a survey instrument designed to measure psychosocial constructs, the ACT student record, and the National Center for Education Statistics. The sample for the study consisted of 12,342 students. Hierarchical generalized linear models and ensemble tree-based methods were utilized to identify important predictors of retention, ascertain the nature of the significant relationships, and to build models for predicting retention outcomes. An initial model was built for prediction before students enrolled followed by a second model with first semester performance variables added. Predictive validity was assessed by splitting the sample into a training and test set. Findings from the study showed that nontraditional factors were significant predictors of retention along with traditional predictors such as high school GPA. The results showed that the influence of financial factors and high school characteristics were among the most significant predictors of retention. Moreover, the results showed that multiple psychosocial factors are influential variables in retention outcomes. This study demonstrated that considering a variety of factors when forecasting postsecondary retention outcomes is vital for more accurate predictions. The models in this study showed that pre-college predictive models have the potential to be nearly as effective as models incorporating college performance and activity. The results of this study have important implications for higher education policymakers, college administrators, and high schools. Several of the relationships revealed have significant policy implications related to budget concerns, university programming, and college preparatory initiatives at the high school level. The study also provides a useful model for identifying students at risk of not being retained that could be adapted for implementation at other institutions and points the importance of a holistic understanding of the total student. [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.]