Forty-three percent of doctoral students never complete their degree. This dropout is the highest among graduate and professional degree programs. Previous cross sectional studies of doctoral students' retention show the importance of financial aid in predicting degree completion. The studies however, do not estimate the labor market's effect on doctoral student retention and neglect the longitudinal nature of doctoral study and the multiple requirements that make doctoral education a three-stage process. This research study examines the effect of various factors, including financial aid and labor market conditions, on the likelihood that doctoral students will complete the three stages of doctoral education: transition, development, and research. Tinto's theory of doctoral persistence and human capital theory formed the conceptual framework for this study. The study will use longitudinal data and survival analysis to model how time influences the various factors that affect doctoral retention. The results show that although financial aid as a whole is important, the type of financial aid received is even more significant and has differential impacts on doctoral students' retention at each stage. Students with research assistantships have the highest likelihood of degree completion compared to students with other forms of financial support. Labor market conditions are also an important factor affecting doctoral student retention. Higher assistant professor salaries motivate doctoral students in the later part of their programs to complete their degrees. [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.]