There is broad support for transforming Payment and Service Delivery Models away from Fee For Service (FFS) and to Value-based Payments (VBP). Centers for Medicare and Medicaid Services Innovation (CMMI) Center has a primary role in testing various payment and service delivery models (PSDMs) that aim to achieve better care for patients, smarter spending and healthier communities. To date, the pilot tests run have been costly, risky, and inconclusive. In this work, we propose a simulation tool developed to improve decision-making before pilot implementation (decrease costs, reduce risk), support evaluation design by identifying key sources of uncertainty (yield more conclusive evaluations), and support program integrity studies (long term monitoring). Our simulation tool is in the early stages of development; we demonstrate it’s value by comparing simulation results with a PSDM previously tested by CMMI, the Federally Qualified Health Centers (FQHC) Advanced Primary Care Practice (APCP) Demonstration.