On September 30, 2015, the Government Accountability Office (GAO) released a report entitled “Medicare: Considerations for Expansion of the Appropriate Use Criteria Program.” In addition to describing CMS’s plans for implementing the imaging Appropriate Use Criteria (AUC) program, the GAO provides examples of non-imaging services deemed “questionable- or low-value” by researchers and for which provider-led entities have developed AUC. The GAO did not evaluate the extent to which the associated AUC are suitable for program implementation, however. In addition, the GAO identified several issues that it considers key to effective implementation of the imaging AUC program or any future expansion of the program, including: effective mapping of clinical indications to applicable AUC; enhancing clinical decision making; designing clinical decision support mechanisms for ease of use; ensuring provider confidence in appropriateness ratings and their underlying evidence; and allowing sufficient preparation time for implementation.