To share an IRIS user's experience designing and implementing an impact measurement program, the Global Impact Investing Network and the Inter-American Development Bank's Opportunities for the Majority (OMJ) Initiative authored this use case. It documents OMJ's approach to measuring, tracking and reporting its social and environmental performance across both its grant and investment portfolio. It also highlights many of the key insights and lessons they learned along the way. OMJ supports impact investments that are market based, commercially viable, replicable, and scalable. It seeks to generate social and economic benefits for the base of the pyramid (BoP) across Latin America and the Caribbean. The IDB Group aims to catalyze additional capital into projects that advance long-term economic development in the region.