The Michigan Contraceptive Access, Research, and Evaluation Study (M-CARES) will use large-scale administrative data, complemented by follow-up surveys and a randomized intervention, to estimate the causal impact of greater financial access to contraception. We will study effects on a broad set of outcomes, including contraceptive use, pregnancy, and parenting strategies; partnership decisions; health care use; education, labor market success, and public assistance receipt; mental health and stress; and life plans. The resulting estimates will inform a more complete understanding of the costs and benefits of financial access to contraception and, therefore, the investment value of related policies and programs.