CalSIM: Modeling the future of health care

As California continues to work to effectively implement the Affordable Care Act (ACA), its leaders require a good understanding of what the likely impacts of the law, and ongoing revisions, will be on its residents -- and the state's budget. To help them, the UCLA Center for Health Policy Research and the UC Berkeley Center for Labor and Research and Education created the California Simulation of Insurance Markets (CalSIM), a micro-simulation model that has been used since 2012 to estimate the impact of various elements of the ACA. CalSIM uses a wide range of official data sources, including the California Health Interview Survey (CHIS).

To date, CalSIM has helped California’s state and local health officials, medical providers, community representatives, insurance companies and others to understand both eligibility and likely enrollment of Californians in the Medi-Cal expansion as well as in the state’s new health insurance exchange, Covered California. Most recently, CalSIM has been used to estimate the impact of state-based reforms to expand subsidies, reinstate the “individual mandate,” and expand eligibility for Medi-Cal coverage for undocumented young adults.