This two-day symposium, held by the American Bar Association Section of Antitrust Law at The George Washington University Law School on 28-29 June 2013, brought together researchers, practitioners, and policymakers to examine the use of retrospective studies to assess past enforcement decisions and improve merger control. The goal of the symposium was to identify lessons from previous studies, discuss state-of-the-art evaluation techniques, and consider how to move the measurement of merger policy quality from an emphasis on outputs to an assessment of outcomes. On the second day of the event, NERA Senior Vice President Dr. Graeme Hunter joined a panel of experts from the European Commission, the Federal Trade Commission, the University of Mannheim, and the University of East Anglia to discuss the existing literature.