Relatively few students from lower socioeconomic backgrounds are enrolled in the most selective American colleges and universities. To improve enrollment, scholars have suggested that college admission offices provide these low SES students an admissions advantage, also known as class-based affirmative action. This study examined to what degree class-based affirmative action is being employed by admissions offices at highly selective colleges. The dataset includes 208,507 records, one for each student application to each of 14 highly selective universities, and includes many factors considered in admissions decisions, such as first generation to college status, which served as this study's proxy for low SES. To reveal correlation between socioeconomic status and two important stages of the College Destination Process--admissions and matriculation--separate from other confounding admission and enrollment factors, such as test scores, gender, and race, a logistic regression analysis was used. This analysis showed an admissions advantage being provided by the set of schools, though the degree of advantage provided by individual schools varied, including one school that put first generation college students at a clear disadvantage. Results were inconclusive for an analysis of the relative likelihood for first generation college students enrolling after having been offered admission, possibly because of important missing variables. The study's overall results confirm the existence of class-based affirmative action among highly selective colleges, while the results by individual college suggest that many colleges could be providing an even greater admissions advantage to first generation college students than they currently do. [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.]