A Natural Experiment to Assess Effects of Medicare Changes

“Advancing Spatial Evaluation Methods to Improve Healthcare Efficiency and Quality” is a research project to assess the effects of particular Medicare health policy changes that were implemented in 2006 in a natural experimental (pre-post) space-time research design, to explore changes in disparities in the utilization of colorectal cancer (CRC) screening and the geographic diffusion of CRC screening technology over time. Selection bias is prevalent, as the elderly selectively enroll in managed care plans, which were significantly impacted by Medicare reforms, and in a geographically disparate fashion.

... with spatial econometric methods for program evaluation 

To assess these effects, we are develop new spatial analytical methods and open source software tools for use in policy evaluations. This includes spatial analytic methods for the explicit joint treatment of spatial dependence, spatial heterogeneity, and selectivity in panel data models and implement them as additions to our well-established software development and dissemination efforts.


One of the results show that the geographic distributions of age and vulnerability among Medicare eligibles changed over the decade, making many markets poorer prospects for managed care plan profitability. The Medicare Modernization Act (MMA) policies strengthened managed care business prospects, and enrollments in Medicare managed care escalated (as illustrated by Figure 1, which shows the penetration by Medicare MA plans in 2005 (before The Act was implemented), and in 2015 (using the most recent data available) across the ten Centers for Medicare & Medicaid Services regions). The MMA also eased budget constraints for seniors, making endoscopic CRC screening more affordable. Endoscopy utilization by Fee-for-Service (FFS) Medicare enrollees increased, and spread geographically to become accessible to most of the continental US. Medicare managed care plan spillovers onto FFS Medicare endoscopy utilization changed over time from a significant negative effect in the early period to no significant effect by the later period. Managed care’s restraining influence on the diffusion of endoscopy changed as it emerged as the gold standard for CRC screening.

This project is funded by the Department of Health and Human Services’ Agency for Healthcare Research and Quality under Award Number 5R01HS021752-04. The funding period is from August 2013 through July 2018. It is directed by Co-PIs Luc Anselin, Stein-Freiler Distinguished Service Professor of Sociology and the College and Director of the Center for Spatial Data Science and Lee Mobley, Associate Professor in Spatial Science and Health Economics at at Georgia State University's School of Public Health and Andrew Young School of Policy Studies. Marynia Kolak, the Research Assistant on the project, is a Ph.D candidate at Arizona State University and Research Specialist at the Center for Spatial Data Science.