Unobserved Heterogeneity in Auctions
Unobserved Heterogeneity in Auctions

Author: Philip A. Haile

Publisher:

Published: 2018

Total Pages: 31

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A common concern in the empirical study of auctions is the likely presence of auction-specific factors that are common knowledge among bidders but unobserved to the econometrician. Such unobserved heterogeneity confounds attempts to uncover the underlying structure of demand and information, typically a primary feature of interest in an auction market. Unobserved heterogeneity presents a particular challenge in first-price auctions, where identification arguments rely on the econometrician's ability to reconstruct from observables the conditional probabilities that entered each bidder's equilibrium optimization problem; when bidders condition on unobservables, it is not obvious that this is possible. Here we discuss several approaches to identification developed in recent work on first-price auctions with unobserved heterogeneity. Despite the special challenges of this setting, all of the approaches build on insights developed in other areas of econometrics, including those on control functions, measurement error, and mixture models. Because each strategy relies on different combinations of model restrictions, technical assumptions, and data requirements, their relative attractiveness will vary with the application. However, this varied menu of results suggests both a type of robustness of identifiability and the potential for expanding the frontier with additional work.

Unobserved Heterogeneity and Reserve Prices in Auctions
Unobserved Heterogeneity and Reserve Prices in Auctions

Author: James W. Roberts

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Published: 2010

Total Pages: 0

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This study addresses the need to account for unobserved heterogeneity in auctions to improve our estimates of the distribution of bidder values. The method uses reserve prices to allow the distribution of bidders' private information to depend on the realization of the unobserved heterogeneity. The identifying assumption is that reserve prices are monotonic in the realization of unobserved heterogeneity and sellers are not required to set reserve prices optimally. The model can be estimated using only transaction prices. The paper proposes an estimation method and derives the asymptotic distribution of the proposed estimator. Working with data on used car auctions, the paper shows that controlling for unobserved heterogeneity affects estimates of the distribution of bidder values and impacts predicted outcomes dramatically.

Nonparametric Identification of First-Price Auctions With Non-Separable Unobserved Heterogeneity
Nonparametric Identification of First-Price Auctions With Non-Separable Unobserved Heterogeneity

Author: David McAdams

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Published: 2010

Total Pages: 0

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We propose a novel methodology for nonparametric identification of first-price auction models with independent private values, which allows for one-dimensional auction-specific unobserved heterogeneity, based on recent results from the econometric literature on nonclassical measurement error in Hu and Schennach (2008). Our approach can accommodate a wide variety of applications in which some location of the conditional distribution of bids (e.g. min or max of the support, mean, etc.) is increasing in the unobserved heterogeneity. This includes settings in which the econometrician fails to observe the reserve price, the cost of bidding, the number of bidders, or some factor (“quality”) with a non-linear effect on bidder values.

Common Values, Unobserved Heterogeneity, and Endogenous Entry in U.S. Offshore Oil Lease Auction
Common Values, Unobserved Heterogeneity, and Endogenous Entry in U.S. Offshore Oil Lease Auction

Author: Giovanni Compiani

Publisher:

Published: 2018

Total Pages: 79

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An oil lease auction is the classic example motivating a common values model. However, formal testing for common values has been hindered by unobserved auction-level heterogeneity, which is likely to affect both participation in an auction and bidders' willingness to pay. We develop and apply an empirical approach for first-price sealed bid auctions with affiliated values, unobserved heterogeneity, and endogenous bidder entry. The approach also accommodates spatial dependence and sample selection. Following Haile, Hong and Shum (2003), we specify a reduced form for bidder entry outcomes and rely on an instrument for entry. However, we relax their control function requirements and demonstrate that our specification is generated by a fully specified game motivated by our application. We show that important features of the model are nonparametrically identified and propose a semiparametric estimation approach designed to scale well to the moderate sample sizes typically encountered in practice. Our empirical results show that common values, affiliated private information, and unobserved heterogeneity-three distinct phenomena with different implications for policy and empirical work-are all present and important in U.S. offshore oil and gas lease auctions. We find that ignoring unobserved heterogeneity in the empirical model obscures the presence of common values. We also examine the interaction between affiliation, the winner's curse, and the number of bidders in determining the aggressiveness of bidding and seller revenue.

Common Values, Unobserved Heterogeneity, and Endogenous Entry in U.S. Offshore Oil Lease Auctions
Common Values, Unobserved Heterogeneity, and Endogenous Entry in U.S. Offshore Oil Lease Auctions

Author: Giovanni Compiani

Publisher:

Published: 2018

Total Pages: 99

ISBN-13:

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In a "common values" environment, some market participants have private information relevant to others' assessments of their own valuations or costs. Economic theory shows that this type of informational asymmetry can have important implications for market performance and market design. Yet even for the classic example of an oil lease auction, formal evidence on the presence and strength of common values has been limited by the problem of auction-level unobserved heterogeneity that is likely to affect both participation in an auction and bidders' willingness to pay. Here we develop an empirical approach for first-price sealed bid auctions with affiliated values, unobserved heterogeneity, and endogenous bidder entry. We show that important features of the model are nonparametrically identified and apply a semiparametric estimation approach to data from U.S. offshore oil and gas lease auctions. Our empirical results show that common values, affiliated private information, and unobserved heterogeneity - three distinct phenomena with different implications for policy and empirical work - are all present. Failing to account for unobserved heterogeneity obscures the empirical evidence of common values. We examine the implications of our estimates for the classic revenue ranking of sealed bid auction designs, and for the interaction between affiliation, the winner's curse, and the number of bidders in determining the aggressiveness of bidding and seller revenue.

Essays on Empirical Auctions and Related Econometrics
Essays on Empirical Auctions and Related Econometrics

Author:

Publisher:

Published: 2014

Total Pages: 218

ISBN-13:

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The first chapter studies identification and estimation of first-price auctions if the bidders face ambiguity about the distribution of valuations. Ambiguity is modeled using Gilboa and Schmeidler's (1989) Maxmin Expected Utility preferences. We exploit variation in the number of bidders to identify the essential primitives of the model. The identification result yields a closed form for the inverse bid function, which suggests a two-step estimation procedure. We study asymptotic and finite sample properties of the estimators. We find evidence of ambiguity in USFS timber auctions which leads to aggressive bidding for bidders with high valuations and has important implications for auction design. The second chapter proposes a procedure to test restrictions on infinite-dimensional parameters (partially) identified by unconditional or conditional moment equalities. Our new method allows us to test restrictions involving a continuum of inequalities. Examples of such restrictions include weakly increasing, concavity and first-order stochastic dominance. We show that our testing procedure controls size uniformly and has power approaching 1 against fixed alternatives. We conduct Monte Carlo Experiments to study the finite sample properties of our procedure. The third chapter studies the inference problem of bidders' risk attitudes in Independent Private Value (IPV) first-price auctions with multiplicative auction-level unobserved heterogeneity. Bidders are assumed to have Constant Relative Risk Aversion. Under the exclusion restriction that bidders randomly select themselves into auctions given the auction-level unobserved heterogeneity, bidders' CRRA coefficient is point-identified from bid data of auctions with at least two different number of active bidders. Our exclusion restriction is consistent with a variety of models with endogenous entry. Empirical application to USFS timber auctions shows that we will conclude that timber firms are risk averse if we ignoring the unobserved heterogeneity. But once we take the unobserved heterogeneity into account, risk neutrality is consistent with the data.

Identification and Estimation of Risk Aversion in First-price Auctions with Unobserved Auction Heterogeneity
Identification and Estimation of Risk Aversion in First-price Auctions with Unobserved Auction Heterogeneity

Author: Serafin Grundi

Publisher:

Published: 2016

Total Pages: 64

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This paper shows point identification in first-price auction models with risk aversion and unobserved auction heterogeneity by exploiting multiple bids from each auction and variation in the number of bidders. The required exclusion restriction is shown to be consistent with a large class of entry models. If the exclusion restriction is violated, but weaker restrictions hold instead, the same identification strategy still yields valid bounds for the primitives. We propose a sieve maximum likelihood estimator. A series of Monte Carlo experiments illustrate that the estimator performs well in finite samples and that ignoring unobserved auction heterogeneity can lead to a significant bias in risk-aversion estimates. In an application to U.S. Forest Service timber auctions we find that the bidders are risk neutral, but we would reject risk neutrality without accounting for unobserved auction heterogeneity.