With the goal of motivating a broader swath of philanthropists to make well-informed, actionable "big bets" to catalyze social change, The Bridgespan Group launched an ambitious research project in partnership with Bridgespan Fellow Jim Shelton. The intent: determine how private donors can best invest to increase upward social mobility for millions of low-income Americans. Collective efforts generated a list of 15 actionable ideas to enhance social mobility for low-income Americans. The Bridgespan Group developed six of these ideas in-depth, working with field experts and practitioners to create roadmaps for making large-scale investments. Part of the intent in developing the six concepts was to ground the ideas by assessing the potential return on investment (ROI) that could be achieved through innovative approaches to using philanthropic capital. This overview outlines the assumptions behind each of the six concepts and the process that was used to calculate each bet's ROI. [For the main report, see ED606509.]