The National Center for Environmental Economics (NCEE) in the EPA Office of Policy requested advice from the Science Advisory Board (SAB) on the use of economy-wide modeling (EWM) for assessing the benefits and costs of air regulations. The agency’s current approach starts with detailed engineering cost assessments (ECAs) that evaluate technical options for compliance in order to produce the expected direct cost of the rules to regulated firms. EPA then uses those costs in partial equilibrium (PE) market models to estimate social costs, which include a broader range of impacts. The agency also uses PE models to evaluate benefits. EPA asked the SAB to: (1) evaluate the technical merits, methodological challenges, and potential value of using EWMs as a supplement to these tools; and (2) to suggest pathways forward that would improve the usefulness of EWMs for regulatory analysis. In response to the EPA’s request, the SAB convened the Economy-Wide Modeling Advisory Panel. The panel held a series of public meetings and teleconferences to deliberate on the charge questions. This report provides the findings and recommendations of the SAB in response to the charge questions