A recent GAO report, "Medicare Advantage: CMS Should Improve the Accuracy of Risk Score Adjustments for Diagnostic Coding Practices," examines differences in diagnostic coding between MA and Medicare fee-for-service plans. Based on its analysis, the GAO concludes that CMS’s 3.4% MA coding adjustment for 2011 and 2012 likely underestimated the impact of coding differences, resulting in excess payments to MA plans. The GAO recommended that CMS improve the accuracy of its MA risk score adjustments by incorporating adjustments for additional beneficiary characteristics, using the most current data available, accounting for all relevant years of coding differences, and incorporating the effect of coding difference trends.