This study operationalized Bekkers and Wiepking's (2007, 2011) eight theoretical mechanisms that drive private giving, examining them within the context of alumni donor behavior at a selected public university in the southern region of the United States. The purpose of the study was to determine if the theoretical mechanisms that drive private giving represent distinct psychometric dimensions, and whether they are correlated with one another or essentially independent. A survey with 24 original items was created for this study, and completed by 178 alumni association member donors and non-member donors from the selected university. The study found support for six factors that are relatively independent of one another, contributing meaningfully to the overall multidimensional construct. The found factors were labeled efficacy, solicitation, reputation, values, altruism, and awareness of need as they fit reasonably well according to their original names. No differences were found between the mean response scores for alumni association member donors and non-member donors across the six dimensions. These results are beneficial for university fundraisers, alumni relations professionals, researchers in the field of philanthropy, and methodologists interested in developing instruments that measure the motivations for private giving. [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.]