My dissertation utilizes an explanatory, sequential mixed-methods research design to assess factors influencing community college students' transfer probability to baccalaureate-granting institutions and to present promising practices in colleges and states directed at improving upward transfer, particularly for low-income and first-generation college students. First, the dissertation features multi-level random-effects model analyses to better understand how factors such as students' academic and social integration, community college characteristics and expenditures, and state transfer policy components influence community college students' 2/4 transfer probability over a recent six-year period (utilizing the Beginning Postsecondary Study 2003-2009). Second, comparative case studies of six community colleges in three states (Florida, Georgia, and Washington) report about how community colleges and state policy leaders currently engage in experimentation and innovation in seeking to improve students' 2/4 transfer, and how they use data to inform decision-making on this issue. The case studies consider ways in which community college and state policy leaders make decisions regarding improving students' transfer prospects, the types of promising initiatives being implemented, and what is being learned from them. The case study design used above-average compared to average performers to illustrate field implementation dynamics that may influence student transfer outcomes, and provide deeper examination of issues affecting community college students as they are making the decision to transfer to a four-year institution, with the goal of improving policies and practices. Similar to other researchers' findings, I found that most state policy variables designed to affect transfer demonstrated little or no statistical association with the probability of transfer, after controlling for state wealth (gross state product per capita (GSP), shown to be associated with the historic rise of state cooperative agreements facilitating transfer in the 1980s and 1990s). Gross state product per capita is also highly positively correlated with the percentage of the state's population with bachelor's degrees, also significantly associated with increased upward transfer probability. The close correlation between state wealth and the proportion of state residents with a bachelor's degree education are likely proxies for a state's social capital and stronger demand for affordable access to college education by state residents, which may be accomplished through 2/4 transfer educational options in the state's public higher education sector. Even though state transfer policy components did not show significant overall effects in the multi-level regression, the presence of common course numbering was associated with increased transfer probability among first generation students (to earn a bachelor's degree), compared with non-first generation students. Findings from the case studies center on four main areas: 1) the role of academic and transfer advising, 2) data use for decision support with respect to improving students' progress toward transfer, 3) leadership strategies for developing and assessing interventions to increase transfer, and 4) the role of state policies in framing and supporting colleges to improve students' upward transfer rates. This dissertation identifies some promising strategies, interventions, and practices among colleges with above-average transfer rates compared with colleges with average transfer rates. While colleges have implemented a range of interventions to improve supports for upward transfer, such as mandatory student advising, transfer fairs and transfer advising programs, there is still considerable room for improvement. Even among the better-performing colleges, too many students, particularly those most at risk of not transferring, may not have sufficient, coordinated supports to successfully complete transfer from their lower-division courses to upper-division coursework leading to a bachelor's degree. (Abstract shortened by UMI.) [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.]