TY  - JOUR
AU  - Ashenfelter,Orley C.
AU  - Hosken,Daniel
AU  - Weinberg,Matthew
TI  - Generating Evidence to Guide Merger Enforcement
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 14798
PY  - 2009
Y2  - March 2009
UR  - http://www.nber.org/papers/w14798
L1  - http://www.nber.org/papers/w14798.pdf
N1  - Author contact info:
Orley C. Ashenfelter
Industrial Relations Section
Firestone Library
Princeton University
Princeton, NJ  08544
Tel: 609/258-4040
Fax: 609/258-2907
E-Mail: c6789@princeton.edu

Daniel Hosken
Federal Trade Commission
600 Pennsylvania Avenue, NW
Washington, DC 20580
E-Mail: dhosken@ftc.gov

Matthew Weinberg
Federal Trade Commission
Mail Stop 4264
600 Pennsylvania Avenue, NW
Washington , DC 20580
E-Mail: mweinberg@ftc.gov
AB  - The challenge of effective merger enforcement is tremendous. U.S. antitrust agencies must, by statute, quickly forecast the competitive effects of mergers that occur in virtually every sector of the economy to determine if mergers can proceed. Surprisingly, given the complexity of the regulators task, there is remarkably little empirical evidence on the effects of mergers to guide regulators. This paper describes the necessity of retrospective analysis of past mergers in building an empirical basis for antitrust enforcement, and provides guidance on the key measurement issues researchers confront in estimating the price effects of mergers. We also describe how evidence from merger retrospectives can be used to evaluate the economic models used to predict the competitive effects of mergers.
ER  -