Experimental Evidence on the Endogenous Entry of Bidders in Internet Auctions

This paper tests the empirical predictions of recent theories of the endogenous entry of bidders in auctions. Data come from a field experiment, involving sealed-bid auctions for collectible trading cards over the Internet. Manipulating the reserve prices in the auctions as an experimental treatment variable generates several results. First, observed participation behavior indicates that bidders consider their bid submission to be costly, and that bidder participation is indeed an endogenous decision. Second, the participation is more consistent with a mixed-strategy entry equilibrium than with a deterministic equilibrium. Third, the data reject the prediction that the profit- maximizing reserve price is greater than or equal to the auctioneerç—´ salvage value for the good, showing instead that a zero reserve price provides higher expected profits in this case.

Field Experiments on the Effects of Reserve Prices in Auctions: More Magic on the Internet

This paper presents experimental evidence on the effects of minimum bids in first-price, sealed-bid auctions. The auction experiments manipulated the minimum bids in a preexisting market on the Internet for collectible trading cards from the game Magic: the Gathering. They yielded data on a number of economic outcomes, including the number of participating bidders, the probability of sale, the levels of individual bids, and the auctioneerç—´ revenues. The benchmark theoretical model tested here is the classic auction model described by Riley and Samuelson (1981), with symmetric, risk-neutral bidders with independent private values. The data verify a number of the predictions of the theory. A particularly interesting result shows that many bidders behave strategically, anticipating the effects of the reserve price on others?bids.

Public Versus Secret Reserve Prices in eBay Auctions: Results from a Pokemon Field Experiment

Sellers in eBay auctions have the opportunity to choose both a public minimum bid amount and a secret reserve price. We ask, empirically, whether the seller is made better or worse off by setting a secret reserve above a low minimum bid, versus the option of making the reserve public by using it as the minimum bid level. In a field experiment, we auction 50 matched pairs of Pok‚mon cards on eBay, half with secret reserves and half with equivalently high public minimum bids. We find that secret reserve prices make us worse off as sellers, by reducing the probability of the auction resulting in a sale, deterring serious bidders from entering the auction, and lowering the expected transaction price of the auction. We also present evidence that some sellers choose to use secret reserve prices for reasons other than increasing their expected auction prices.

Online Auctions

The economic literature on online auctions is rapidly growing because of the enormous amount of freely available field data. Moreover, numerous innovations in auction-design features on platforms such as eBay have created excellent research opportunities. In this article, we survey the theoretical, empirical, and experimental research on bidder strategies (including the timing of bids and winner's-curse effects) and seller strategies (including reserve-price policies and the use of buy-now options) in online auctions, as well as some of the literature dealing with online-auction design (including stopping rules and multi-object pricing rules).

Bidding Behavior and Decision Costs in Field Experiments

Whether rationality of economic behavior increases with expected payoffs and decreases with the cognitive cost it takes to formulate an optimal strategy remains an open question. We explore these issues with field data, using individual bids from sealed-bid auctions in which we sold nearly $10,000 worth of sports cards. Our results incdicate that stakes do indeed matter, as high-priced ($70) cards produced more of the theoretically predicted strategic behavior than did lower-priced ($3) cards. We find additional evidence consistent with the importance of cognitive costs, as subjects more experienced with sports card auctions exhibited a greater tendency to behave strategically than did less experienced bidders.

Recombinant Estimation for Normal-Form Games, with Applications to Auctions and Bargaining

In empirical analysis of economic games, researchers frequently wish to estimate quantities describing group outcomes, such as the expected revenue in an auction or the mean allocative efficiency in a market experiment. For such applications, we propose an improved statistical estimation technique called "recombinant estimation." The technique takes observations of the complete strategy of each player and recombines them to compute all the possible group outcomes which could have resulted from different matches of players. We calculate the improvement in efficiency of the recombinant estimator relative to the standard estimator, and show how to estimate standard errors for the recombinant estimator for use in hypothesis testing. We present an application to a two-player sealed-bid auction and a two-player ultimatum bargaining game. In these applications, the improved efficiency of our estimator is equivalent to an increase of between 40% and 200% in the sample size. We discuss how to design game experiments in order to be able to take full advantage of recombinant estimation. Finally, we discuss practical computational issues, showing how one can avoid combinatorial explosions of computing time while still yielding significantly improved efficiency of estimation.

Using field experiments to test equivalence between auction formats: Magic On the Internet

William Vickrey's predicted equivalences between first-price sealed-bid and Dutch auctions, and between second-price sealed-bid and English auctions, are tested using field experiments that auctioned off collectible trading cards over the Internet. The results indicate that the Dutch auction produces 30-percent higher revenues than the first-price auction format, a violation of the theoretical prediction and a reversal of previous laboratory results, and that the English and second-price formats produce roughly equivalent revenues.

"The War for the Fare": How Driver Compensation Affects Bus System Performance

Two systems of bus driver compensation exist in Santiago, Chile. Most drivers are paid per passenger transported, while a second system compensates other drivers with a fixed wage. Compared with fixed-wage drivers, per-passenger drivers have incentives to engage in "La Guerra por el Boleto" ("The War for the Fare"), in which drivers change their driving patterns to compete for passengers. This paper takes advantage of a natural experiment provided by the coexistence of these two compensation schemes on similar routes in the same city. Using data on intervals between bus arrivals, we find that the fixed-wage contract leads to more bunching of buses, and hence longer average passenger wait times. The per-passenger drivers are assisted by a group of independent information intermediaries called "sapos" who earn their living by standing at bus stops, recording arrival times, and selling the information to subsequent drivers who drive past. We find that a typical bus passenger in Santiago waits roughly 10% longer for a bus on a fixed-wage route relative to an incentive-contract route. However, the incentives also lead drivers to drive noticeably more aggressively, causing approximately 67% more accidents per kilometer driven. Our results have implications for the design of incentives in public transportation systems.