Dominic Coey

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We introduce a simple and robust approach to address several key questions in empirical auction analysis: testing for dependence between bidders’ valuations and the number of entrants, and quantifying the revenue effects of improved auction design or from bidder mergers or collusion. The approach applies in a broad range of information settings, including(More)
Identifying the same internet user across devices or over time is often infeasible. This presents a problem for online experiments, as it precludes person-level randomization. Randomization must instead be done using imperfect proxies for people, like cookies, email addresses, or device identifiers. Users may be partially treated and partially untreated as(More)
Classical statistical inference of experimental data assumes that the treatment affects the test group but not the control group. This assumption will typically be violated when experimenting in marketplaces because of general equilibrium effects: changing test demand affects the supply available to the control group. We illustrate this with an email(More)
We present an equilibrium search model that parsimoniously rationalizes several defining patterns of online markets for new goods. We model buyers in these markets as having a deadline by which the good must be purchased and we model sellers’ choice between auctions and fixed-price mechanisms. As the deadline approaches, buyers increase their bids and are(More)
I use data from an online financial service to show that many consumers fail to stick to their self-set debt paydown plans, and argue that this behavior is best explained by present bias. Each user’s sensitivity of consumption spending to paycheck receipt proxies for his short-run impatience. I empirically distinguish between consumers who are aware(More)
This paper provides a positive identification result for procurement models with asymmetric bidders, statistically dependent private information, and interdependent costs. When bidders are risk neutral, the model’s payoff-relevant primitives are: (i) the joint distribution of private information and (ii) each bidder’s fullinformation expected cost—the(More)
We estimate how physicians’ financial incentives affect their treatment choices in heart attack management, using a large dataset of private health insurance claims. Different insurance plans pay physicians different amounts for the same services, generating the required variation in financial incentives. We begin by presenting evidence that,(More)
We consider a population of buyers who have unit demand for a homogeneous good, and only differ in terms of how soon they need to purchase it. These buyers have access to a stochastic stream of second-price auctions, as well as posted-price listings that can be used at any time. Using the tools of equilibrium search theory, we characterize the equilibrium(More)