As promised, Mark McClellan, former administrator of the centers for Medicare and Medicaid Services has joined the think tank world. McClellan will focus on developing ways to improve health care and its costs as a senior fellow for regulatory studies at two think tanks – The Brookings Institute and the American Enterprise Institute. In his new role, McClellan will focus on identifying steps to speed development of new treatments and reforming payment and regulatory systems, according to a joint statement from the organizations.