Posted Prices and Bid Affiliation: Evidence from Experimental Auctions

In most experimental auctions, researchers ask participants to bid on the same item in multiple potentially binding rounds, posting the price submitted by the top bidder or bidders after each of those rounds. If bids submitted in later rounds are affiliated with posted prices from earlier rounds, this practice could result in biased value estimates. In this article we discuss the results of an experiment designed explicitly to test whether posted prices affect bidding behavior. We find that for familiar items, high posted prices lead to increased bids in subsequent rounds. Our results have implications for researchers conducting experimental auctions.Experimental Auctions, Posted Prices, Affiliation

Makespan Minimization via Posted Prices

We consider job scheduling settings, with multiple machines, where jobs arrive online and choose a machine selfishly so as to minimize their cost. Our objective is the classic makespan minimization objective, which corresponds to the completion time of the last job to complete. The incentives of the selfish jobs may lead to poor performance. To reconcile the differing objectives, we introduce posted machine prices. The selfish job seeks to minimize the sum of its completion time on the machine and the posted price for the machine. Prices may be static (i.e., set once and for all before any arrival) or dynamic (i.e., change over time), but they are determined only by the past, assuming nothing about upcoming events. Obviously, such schemes are inherently truthful. We consider the competitive ratio: the ratio between the makespan achievable by the pricing scheme and that of the optimal algorithm. We give tight bounds on the competitive ratio for both dynamic and static pricing schemes for identical, restricted, related, and unrelated machine settings. Our main result is a dynamic pricing scheme for related machines that gives a constant competitive ratio, essentially matching the competitive ratio of online algorithms for this setting. In contrast, dynamic pricing gives poor performance for unrelated machines. This lower bound also exhibits a gap between what can be achieved by pricing versus what can be achieved by online algorithms

Quantitative restrictions in experimental posted-offer markets

The effect of imposing binding and non-binding quantity restrictions upon price convergence in posted-offer markets is discussed. Unlike in the price control experiments prices do not jump after the removal of quantity restrictions. Further, a surprising property of prices was observed in these experiments, prices converge from below the competitive equilibrium. This result contradicted the well established empirical regularity that price convergence is from above the competitive equilibrium in Posted-Offer markets. Thus, the asymmetric distribution of surplus, or the imposition of quotas themselves affected price convergence in the quota experiments

Sequential Posted Price Mechanisms with Correlated Valuations

We study the revenue performance of sequential posted price mechanisms and some natural extensions, for a general setting where the valuations of the buyers are drawn from a correlated distribution. Sequential posted price mechanisms are conceptually simple mechanisms that work by proposing a take-it-or-leave-it offer to each buyer. We apply sequential posted price mechanisms to single-parameter multi-unit settings in which each buyer demands only one item and the mechanism can assign the service to at most k of the buyers. For standard sequential posted price mechanisms, we prove that with the valuation distribution having finite support, no sequential posted price mechanism can extract a constant fraction of the optimal expected revenue, even with unlimited supply. We extend this result to the the case of a continuous valuation distribution when various standard assumptions hold simultaneously. In fact, it turns out that the best fraction of the optimal revenue that is extractable by a sequential posted price mechanism is proportional to ratio of the highest and lowest possible valuation. We prove that for two simple generalizations of these mechanisms, a better revenue performance can be achieved: if the sequential posted price mechanism has for each buyer the option of either proposing an offer or asking the buyer for its valuation, then a Omega(1/max{1,d}) fraction of the optimal revenue can be extracted, where d denotes the degree of dependence of the valuations, ranging from complete independence (d=0) to arbitrary dependence (d=n-1). Moreover, when we generalize the sequential posted price mechanisms further, such that the mechanism has the ability to make a take-it-or-leave-it offer to the i-th buyer that depends on the valuations of all buyers except i's, we prove that a constant fraction (2-sqrt{e})/4~0.088 of the optimal revenue can be always be extracted.Comment: 29 pages, To appear in WINE 201

Equivalence of Auctions and Posted Prices

We determine the equilibrium in two transaction mechanisms: auctions and posted prices. Agents choose whether to participate in markets where trades are consummated by auctions or in markets where sellers post prices. We show that the selling mechanisms are practically equivalent. Previous studies have shown that auction markets emerge as a unique evolutionary stable equilibrium when compared to bargaining markets. Posted price market dominate bargaining markets similarly.Auctions;posted prices;random matching.

The Citation Impact of Digital Preprint Archives for Solar Physics Papers

Papers that are posted to a digital preprint archive are typically cited twice as often as papers that are not posted. This has been demonstrated for papers published in a wide variety of journals, and in many different subfields of astronomy. Most astronomers now use the arXiv.org server (astro-ph) to distribute preprints, but the solar physics community has an independent archive hosted at Montana State University. For several samples of solar physics papers published in 2003, I quantify the boost in citation rates for preprints posted to each of these servers. I show that papers on the MSU archive typically have citation rates 1.7 times higher than the average of similar papers that are not posted as preprints, while those posted to astro-ph get 2.6 times the average. A comparable boost is found for papers published in conference proceedings, suggesting that the higher citation rates are not the result of self-selection of above-average papers.Comment: 5 pages, 1 table, Solar Physics accepte

Posted Pricing as a Plus Factor

This paper identifies conditions under which an industry-wide practice of posted (or list) pricing is a plus factor sufficient to conclude that firms violated Section 1 of the Sherman Act. For certain classes of markets, it is shown that, under competition, all firms setting a list price with a policy of no discounting is contrary to equilibrium. Thus, if all firms choose posted pricing, it is to facilitate collusion by making it easier for them to coordinate their prices. It is then argued that the adoption of posted pricing communicates the necessary intent and reliance to conclude concerted action.