Impact Evaluation of Merger Decisions

This paper provides a comparative analysis of methods for the empirical ex post evaluation of merger control decisions. It develops a competition-policy oriented framework of assessment criteria for the leading evaluation methods and applies them to structural modeling and simulation, differences-in-differences methods, event studies as well as survey-based methods. It concludes that a method-mix is recommendable, however, under the exclusion of event studies that fail to secure a minimum level of reliability regarding the evaluation results. Furthermore, it warns against overly optimistic expectations about the effects of systematic impact evaluations of merger decisions. I like to thank the participants of the OECD Roundtable „Impact Evaluation of Merger Decisions“ (Paris, Juni 2011), Arndt Christiansen and Knud Sinding for valua-ble comments on earlier versions of this paper as well as Janne Mordhorst for valuable editorial assistance.