The 2010 Patient Protection and Affordable Care Act (ACA) calls for significant policy changes that have meaningful and widespread implications for the U.S. health system. Given the magnitude and breadth of these provisions, policymakers and analysts need tools to estimate the potential effects on the health system and its participants. Microsimulation modeling is one such tool, serving as a mechanism for estimating the potential behavioral and economic effects of public policies on decision-making units.

This brief explains the basics of microsimulation modeling so that policymakers and analysts are able to secure the optimal model for their needs. With this in mind, the brief addresses three questions:

1. What are health policy microsimulation models and what are their components?
2. What are the similarities and differences among the five major federal health policy models?
3. What types of questions should policymakers and analysts consider when evaluating contracting options for health policy microsimulation?

See also the archive of a companion webinar held on March 21, 2012, "Predicting the Effects of the ACA - Understanding Microsimulation Models."