Medicare Advantage, CMS should fully develop plans for encounter data and assess data quality before use

" Medicare Advantage-the private plan alternative to the traditional Medicare program-provides health care for nearly 15.5 million enrollees, about 30 percent of all Medicare beneficiaries. After a multiyear rollout, CMS began collecting encounter data in January 2012. GAO was asked to review CMS's plans for using MA encounter data and its efforts to validate the data's quality. This report examines (1) how the scope of MA encounter data compare with CMS's current risk adjustment data, (2) the extent to which CMS has specified plans and time frames to use encounter data for risk adjustment and other purposes, and (3) the extent to which CMS has taken appropriate steps to ensure MA encounter data's completeness and accuracy. In addition to reviewing laws, regulations, and guidance on MA encounter data collection and reporting, GAO interviewed CMS officials and representatives of MAOs. GAO also compared CMS's activities to the protocol CMS developed to validate Medicaid encounter data-comparable data collected and submitted by entities similar to MAOs. "