Inconvenient Truths on Merger Retrospective Studies

Gregory J. Werden, U.S. Department of Justice - Antitrust Division offers Inconvenient Truths on Merger Retrospective Studies.

ABSTRACT: Inconvenient truths prevent merger retrospective studies from substantially altering our understanding of competitive effects from horizontal mergers. Merger retrospectives cannot definitively determine the effects of particular mergers, and if they could, merger retrospectives still could not provide evidence supporting merger assessments grounded in data on actual merger effects rather than in economic theory and legal presumptions. If merger retrospectives are to have some prospect of recalibrating merger enforcement, they must be transformed from econometric exercises into case studies examining the details of the relevant agency’s assessment, but inconvenient truths likely prevent much from being learned through even such studies.