Adult students are an important component of the current U.S education landscape. They account for over 40% of the degree-seeking fresh enrollees in the U.S. colleges and according to the U.S. Department of Education, their growth will soon outpace that of traditional students. Adult students have also received considerable attention in higher education policy circles as an important resource to meet the future skills demand in U.S. industries. The focus on adult students is integral to sustaining the health of the U.S economy. Chapters in this dissertation aim to understand and quantify issues surrounding adult students. Chapter 1 of this dissertation analyzes the characteristics and factors that help or inhibit the decisions to return to school of adult students. Using an endogenous switching model and data from the Survey of Income Program and Participation (SIPP) 2008, I examine the determinants of the return decision. The results show positive selection bias from observed earnings of those who return, and the probability of returning to school hinges significantly on family size, family income, and the presence of children under 18. Chapter 2 analyzes the pecuniary returns to returning adults using the National Longitudinal Youth Survey of 1979 (NLSY79). I find 10-20% returns to returning adults across different education degrees. I also find that the post-return experience premium is higher for returners relative to non-returners. Chapter 3 analyzes the degree of persistence or state dependence in enrollment behavior of adult students using NLSY data from 1989-1994 and dynamic panel estimation methods. The results suggest that state dependence effects exist with respect to the previous enrollment incidence for men and women. For men I find that about 20% of the observed persistence in the enrollment probability is accounted for by state-dependence, as compared with roughly 36% for women. [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.]