Pure Numbers Effects, Market Power, and Tacit Collusion in Posted Offer Markets

This paper studies the effects of seller concentration and static market power on tacit collusion in extensively repeated laboratory posted-offer markets. Contrary to the implications of some earlier research, we find that tacit collusion does not become pervasive with extensive repetition. In a ‘strong no power’ design persistently competitive outcomes are observed in markets with three or four sellers. Even duopolies are frequently competitive in this design. Unilateral market power raises prices, as predicted. However, static Nash predictions fail to organize outcomes across power treatments, because tacit collusion moves inversely with concentration. Excess capacity appears to explain observed tacit collusion levels.experiments, market concentration, market power

Rebate Subsidies, Matching Subsidies and Isolation Effects

In a series of recent experiments (Davis, Millner and Reilly, 2005, Eckel and Grossman, 2003, 2005a-c, 2006), matching subsidies generate significantly higher charity receipts than do theoretically equivalent rebate subsidies. This paper reports a laboratory experiment conducted to examine whether the higher receipts are attributable to a relative preference for matching subsidies or to an ‘isolation effect’ (McCaffery and Baron, 2003, 2006). Some potential policy implications of isolation effects on charitable contributions are also considered.experiments, charitable contributions, methodology

Posted - Offer Markets In Near Continuous Time: an Experimental Investigation

This paper reports an experiment conducted to evaluate a ‘near continuous’ variant of the posted-offer trading institution, where the number of periods in a market session is increased by reducing sharply each period’s maximum length. Experimental results suggest that although decisions in time-truncated periods are not equivalent to periods of longer duration, extensive repetition improves considerably the drawing power of equilibrium predictions in some challenging environments. Nevertheless, significant deviations remain in the near continuous framework. We also observe that the extra data collected in the near continuous framework allows new insights into price convergence and price signaling.experiment, monopoly, pricing, price signaling

Nominal Price Shocks in Monopolistically Competitive Markets: An Experimental Analysis

We report a market experiment that examines the capacity of price and information frictions to explain real responses to nominal price shocks. As predicted by the standard dynamic adjustment models, we find that both price and information frictions impede the response to a nominal shock. We also find, however, that the observed adjustment delays far exceed predicted levels. Results of a pair of subsequent treatments indicate that a combination of announcing the shock privately to all sellers (rather than publicly) and a failure of many sellers to best respond to their expectations explains the observed adjustment inertia.Market Experiments, Price Rigidities, Information Rigidities, Bounded Rationality

Experimental economics: Methods, problems and promise

The purpose of this paper is to discuss the growing importance of experimentation in economic analysis. We present a variety of economic issues that have been explored with laboratory techniques. We also address some common objections to experimentation, as well as some of the principal lessons that have been learned.

Strategic Buyers, Horizontal Mergers and Synergies: An Experimental Investigation*

This paper reports an experiment designed to evaluate interrelationships between strategic buyers, market power and merger-induced synergies. The experiment consists of 40 posted-offer quadropolies. Treatments include the use of simulated or human buyers, seller consolidations and merger-induced fixed cost and unit cost synergies. In the simulated-buyer markets we observe behavior generally consistent with comparative static predictions: prices rise post-merger, and unit (but not fixed) cost synergies may exert some price-moderating effect. The addition of powerful buyers changes results markedly. Although prices are lower in the human buyer markets, outcomes are more variable and predicted comparative static effects are no longer observed.

Experimental Economics

This is the first comprehensive treatment of laboratory experiments designed to evaluate economic propositions under carefully controlled conditions. While it acknowledges that laboratory experiments are no panacea, it argues cogently for their effectiveness in selected situations. Covering methodological and procedural issues as well as theory, Experimental Economics is not only a textbook but also a useful introduction to laboratory methods for professional economists. The emphasis is on organizing and evaluating existing results. The book can be used as an anchoring device for a course at either the graduate or advanced undergraduate level. Applications include financial market experiments, oligopoly price competition, auctions, bargaining, provision of public goods, experimental games, and decision making under uncertainty. The book also contains instructions for a variety of laboratory experiments.laboratory experiments, financial markets, price competition, auctions, bargaining, games, decision making, uncertainty

Re-matching, Information and Sequencing Effects in Posted Offer Markets

This paper evaluates the effects of some standard procedural variations on outcomes in posted offer oligopoly experiments. Variations studied include the presence or absence of market information, the use of re-matching or fixed seller pairs and alterations in the order of sequencing. Experimental results indicate that such variations can have first order effects on outcomes. For this reason, we recommend that results in oligopoly experiments be carefully interpreted in light of the procedures selected.Market Experiments, Oligopoly, Re-Matching, Information, Market Concentration

Cooperation without Coordination: Signaling, Types and Tacit Collusion in Laboratory Oligopolies

We study the effects of price signaling activity and underlying propensities to cooperate on tacit collusion in posted offer markets. The primary experiment consists of an extensively repeated baseline sequence and a 'forecast' sequence that adds to the baseline a forecasting game that allows identification of signaling intentions. Forecast sequence results indicate that signaling intentions considerably exceed those that are counted under a standard signal measure based on previous period prices. Nevertheless, we find essentially no correlation between either measure of signal volumes and collusive efficiency. A second experiment demonstrates that underlying seller propensities to cooperate more clearly affect collusiveness.Experiments, Tacit Collusion, Price Signaling, TypesExperiments, Tacit Collusion, Price Signaling, Types

Behavioral Convergence Properties of Cournot and Bertrand Markets: An Experimental Analysis

This paper reports an experiment that examines the relative convergence properties of differentiated-product Cournot and Bertrand oligopolies. Overall, Bertrand markets tend to converge to Nash equilibrium predictions more quickly and more completely than Cournot markets. Further, when products are close substitutes Bertrand markets respond more quickly to an announced nominal shock. As products become weaker substitutes, however, an increased tendency for tacit collusion degrades convergence in Bertrand markets. This effect is particularly pronounced following a nominal shock. Our results suggest that in an oligopoly context variations in decision error costs dominate a 'Strategic Substitutes Effect' isolated in previous experimental research.Experiments, Strategic Substitutes and Strategic Complements, Bertrand and Cournot Markets