Dominic Coey

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NBER Working Papers and Publications

June 2018The Simple Empirics of Optimal Online Auctions
with Bradley Larsen, Kane Sweeney, Caio Waisman: w24698
We study reserve prices computed to maximize the expected profit of the seller based on historical observations of incomplete bid data typically available to the auction designer in online auctions for advertising or e-commerce. This direct approach to computing reserve prices circumvents the need to fully recover distributions of bidder valuations. We derive asymptotic results and also provide a new bound, based on the empirical Rademacher complexity, for the number of historical auction observations needed in order for revenue under the estimated reserve price to approximate revenue under the optimal reserve arbitrarily closely. This simple approach to estimating reserves may be particularly useful for auction design in Big Data settings, where traditional empirical auctions methods may ...
February 2016A Theory of Bidding Dynamics and Deadlines in Online Retail
with Bradley Larsen, Brennan Platt: w22038
We present an equilibrium search model that parsimoniously rationalizes the use of auctions as a sales mechanism for new-in-box goods--a frequent occurrence in online retail markets--and analyze whether the existence of these auctions is welfare enhancing relative to a market consisting only of posted prices. Buyers have a deadline by which the good must be purchased, and sellers choose between auctions and posted-price mechanisms. As the deadline approaches, buyers increase their bids and are more likely to buy through posted-price listings. The model predicts equilibrium price dispersion even for new, homogeneous goods. Using data on one million auction and posted-price listings for new-in-box items on, we find robust evidence consistent with our model. As predicted, bidders inc...
September 2014The Bidder Exclusion Effect
with Bradley Larsen, Kane Sweeney: w20523
We introduce a simple and robust approach to answering two key questions in empirical auction analysis: discriminating between models of entry and quantifying the revenue gains from improving auction design. The approach builds on Bulow and Klemperer (1996), connecting their theoretical results to empirical work. It applies in a broad range of information settings and auction formats without requiring instruments or estimation of a complex structural model. We demonstrate the approach using US timber and used-car auction data.
March 2011Set-Asides and Subsidies in Auctions
with Susan Athey, Jonathan Levin: w16851
Set-asides and subsidies are used extensively in government procurement and natural resource sales. We analyze these policies in an empirical model of U.S. Forest Service timber auctions. The model fits the data well both within the sample of unrestricted sales where we estimate the model, and when we predict (out of sample) bidder entry and prices for small business set-asides. Our estimates suggest that restricting entry to small businesses substantially reduces efficiency and revenue, although it does increase small business participation. An alternative policy of subsidizing small bidders would increase revenue and small bidder profit, while eliminating almost all of the efficiency loss of set-asides, and only slightly decreasing the profit of larger firms. We explain these findings by...

Published: Susan Athey & Dominic Coey & Jonathan Levin, 2013. "Set-Asides and Subsidies in Auctions," American Economic Journal: Microeconomics, American Economic Association, vol. 5(1), pages 1-27, February. citation courtesy of

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