The Hart Scott Rodino program, coupled with the modern Merger Guidelines has structured merger enforcement for the last twenty years. This paper reviews all of the filings on which the Commission issued a second request. While horizontal mergers predominate, vertical, potential competition and...

The rise of unilateral effects analysis, as quantified by merger simulation, creates the potential to balance anticompetitive effects and efficiencies and improve the merger review process. Unfortunately, sophisticated economic models impose a tight structure on the analytical process, one that...

To be admissible in federal court under the Daubert standard, expert economic testimony must be (1) based on scientific analysis and (2) aid the dispute resolution process. Expert evidence should be considered scientific when (1) it meets Karl Popper’s falsification standard and (2) some...

The 2010 revision of the Merger Guidelines highlighted the importance of both economic modeling of the post-merger competitive process and effects evidence, defined as information able to predict the transaction’s likely competitive effect. With sufficient data, it is possible to see how...

We collect a sample of EU and US merger investigations, estimate models of the regulatory decisions, and use the models to compare merger policies. Our approach allows us to decompose observed differences into policy effects and case-mix effects. Focusing on dominance mergers, we find that the...