Estimating current-law health care spending of Medicare Advantage enrollees for use in microsimulation modeling of Medicare policies Shartzer, Adele, author. Garrett, Bowen, author. Arnos, Diane, author. Banthin, Jessica, author. Gangopadhyaya, Anuj, author. Health Expenditures Medicare Part C Models, Economic Microsimulation modeling of Medicare policy reforms requires estimates of spending for all Medicare enrollees, but quality spending data for Medicare Advantage (MA) enrollees are not generally available. MA is a large and growing part of the Medicare program, however, having accounted for 34 percent of Medicare program spending in 2019. In this methods brief, we describe our approach to estimating county-level MA program spending and spending by MA enrollees using plan- and county-level data from the Centers for Medicare & Medicaid Services. We generate our estimates in MCARESIM, the Urban Institute’s microsimulation model for estimating the effects of Medicare policy reforms. These estimates can be used as inputs for analyses of changes in Medicare policy. Washington, DC : Urban Institute, January 2021 Urban Institute, issuing body. Technical Report Text Illustrations 1 online resource (1 PDF file (19 pages)) nlm:nlmuid-9918266199806676-pdf 9918266199806676 http://resource.nlm.nih.gov/9918266199806676 English United States Reproduced with permission of the copyright holder. Further use of the material is subject to CC BY-NC-DC license. https://creativecommons.org/licenses/by-nc-nd/3.0