Following merger, an optimal mechanism discriminates against merging bidders with higher reserve prices and by allocating more often towards non-merging bidders. In this setting, we show that mergers always harm the auctioneer, benefit non-merging bidders, can increase total surplus, and have...

In this paper, we characterize adversarial decision-making as a choice between competing interpretations of evidence ("models") constructed by interested parties. We show that if a court cannot perfectly determine which party's model is more likely to have generated the evidence, then...

In a private values, open auction, we show that bidder surplus can be expressed as a simple difference between unconditional moments of order statistics. The strength of the result is its simplicity and generality, as we dispense with the typical assumptions of independence and/or symmetry. We...

We propose a simple method for predicting price effects from mergers between branded retail chains competing in many local markets. When past mergers created markets with the same number of brands but different numbers of brand owners, price data at a single point in time exhibit between-market...

This paper introduces a simple free web app that can teach regression to anyone who can point and click. Originally designed to teach Justice Department attorneys enough about regression so that they could cross examine rival experts, the app ``inverts'' the usual pedagogy: instead of showing...

Health plans create competition among hospitals by threatening to “steer” patients to preferred facilities. Mergers can reduce this competition and economists have begun using travel cost demand models to predict their effects. In this paper, we document an anomaly in estimation: for any...

For 181 million Americans not on Medicare or Medicaid but insured through their employer, labor union, or private insurance health plan, the primary restraints on pharmaceutical prices are pharmaceutical benefit managers (PBMs) who administer health plan drug benefits. PBMs use the aggregate...