The recent growth in the racial and cultural heterogeneity of college students in the United States has increased the demand for higher educational policies that will accommodate the needs of an increasingly diverse collective student body (Kao & Thompson, 2003). Traditionally, underrepresented minority students (i.e., African American, Hispanic and American Indian) persist in colleges at a lower rate compared to non-Hispanic, white and Asian students. There is evidence that minority students fail to persist because of limited or unsuccessful attempts by postsecondary institutions to help improve academic and social integration of these students in colleges (Seymour & Hewitt, 1997; Maton, Hrabowski & Schmitt, 2004; Summers & Hrabowski, 2006). In addition, many students receive inadequate family and financial support because their parents lack college education. Finally, Hispanics who are currently the largest minority group in the U.S., are more likely to be immigrants. Hispanic immigrants are one of the most vulnerable racial/ethnic groups with the lowest levels of academic success (Passel, 2005). In my dissertation, I analyze three educational strategies adopted by higher education institutions with the goal of improving educational outcomes for the most vulnerable groups such as first-generation, minority and immigrant students. In the first essay, I explore the importance of financial aid for students whose parents have low levels of education. I find that the availability of federally funded need-based aid lowers attrition rates of first-generation college students. Second, I explore the significance of undergraduate research opportunities for minority students in science fields. My results indicate that summer research opportunities obtained at academic and government sites increase participation of underrepresented minority students in science Ph.D. programs. Finally, in my third essay, I address the impact of changes in tuition prices on the educational outcomes of college students who are not U.S. citizens at two universities in Texas and find some evidence that the reduction in tuition costs improves college affordability for these students. [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.]