This note outlines the methodology for developing Evidence Gap Maps (EGMs) as adapted for the Inter-American Development Bank, positioning them as tools to enhance the quality and impact of development policies and operations. EGMs compile and structure existing studies to highlight evidence clusters and gaps around specific topics, guiding institutions to target resources where they can have the greatest effect. The note outlines the main steps involved in building an EGM and draws lessons from two EGMs recently developed by the IDB, including one prepared jointly with the International Initiative for Impact Evaluation (3ie). Beyond documenting available evidence, EGMs can inform policy dialogue and guide operational design, contributing to more effective use of public resources. Looking ahead, new technologies and software will allow EGMs to be produced more quickly and of higher quality, making them an increasingly powerful tool for policymakers and practitioners.