Thomas J Hwang1, Daniel Carpenter2, Aaron S Kesselheim3. 1. Faculty of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA. The Blackstone Group, London W1J 5AL, UK. tjhwang@post.harvard.edu akesselheim@partners.org. 2. Faculty of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA. Radcliffe Institute for Advanced Study, Harvard University, Cambridge, MA 02138, USA. 3. Program On Regulation, Therapeutics, And Law (PORTAL), Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02120, USA. tjhwang@post.harvard.edu akesselheim@partners.org.