Coordination of mobile labor

We study coordination failures in many simultaneously occurring coordination problems. Players encounter one of the problems but have the outside option of migrating to one of the remaining ones. Drawing on the global games approach, we show that such a mobile game has a unique equilibrium that allows us to examine comparative statics. The endogeneity of the outside option value and of the migration activity leads to non-monotonicity of welfare with respect to mobility friction; high mobility may hurt players. We apply these “general equilibrium’’ findings to the problem of the labor market during industrialization as described by Matsuyama [Increasing returns, industrialization and indeterminacy of equilibrium, Quart. J. Econ. 106 (1991) 617-650].     

The impact of bargaining on markets with price takers: Too many bargainers spoil the broth

In this paper we study how bargainers impact on markets in which firms set a list price to sell to those consumers who take prices as given. The list price acts as an outside option for the bargainers, so the higher the list price, the more the firms can extract from bargainers. We find that an increase in the proportion of consumers seeking to bargain can lower consumer surplus overall, even though new bargainers receive a lower price. The reason is that the list price for those who do not bargain and the bargained prices for those who were already bargaining rise: sellers have a greater incentive to make the bargainers’ outside option less attractive, reducing the incentive to compete for price takers. Competition Authority exhortations to bargain can therefore be misplaced. We also consider the implications for optimal seller bargaining.     

Discounting and altruism to future decision-makers

Is discounting of future decision-makers’ consumption utilities consistent with “pure” altruism toward those decision-makers, that is, a concern that they are better off according to their own, likewise forward-looking, preferences? It turns out that the answer is positive for many but not all discount functions used in the economics literature. In particular, “hyperbolic” discounting of the form used by Phelps and Pollak (Rev. Econ. Studies 35 (1968) 201) and Laibson (Quart. J. Econ. 112 (1997) 443) is consistent with exponential altruism towards future generations. More generally, we establish a one-to-one relationship between discount functions and altruism weight systems, and provide sufficient, as well as necessary, conditions for discount functions to be consistent with pure altruism.     

Buyer power and supplier incentives

This paper analyzes the origins and welfare consequences of buyer power. We show that if suppliers are capacity constrained or have strictly convex costs, there are two different channels through which large buyers can obtain more favorable terms from their suppliers. In particular, we show how the presence of large buyers can then erode the value of suppliers’ outside option. Somewhat surprisingly, we show how this can induce suppliers to undertake strategies that lead to higher output and potentially higher welfare.     

Real options and demographic decisions

The theory of real options is used to incorporate the influence of uncertainty on demographic decision-making. The decision to have children is formulated as an investment using portfolio theory. The timing of the decision to have a child is modelled as a real options decision, with uncertainty affecting a woman's ability to exercise the ‘option to wait’ in order to delay or space births. An increase and reduction in uncertainty on this option is explored. Compared to the widely used net present value (NPV) framework, the real options approach (ROA) better explains the process of demographic decision-making in poor countries.     

Hope springs eternal: learning and the stability of cooperation in short horizon repeated games

This paper considers learning rates in finitely repeated prisoners’ dilemmas. If players think their opponents might be relatively cooperative (e.g., tit-for-tat or grim types), they will cooperate in finitely repeated prisoners’ dilemmas (see Kreps et al., J. Econom. Theory 27 (1982) 245). However, if there are actually no cooperative types, players will eventually learn this and cooperation will break down. This paper shows that this learning is extremely slow, so it will take an extremely long time for cooperation to break down.Thus, suppose the world is either “good” or “bad.” The probability of a grim type is δ>0 if the world is good, and zero if the world is bad. Successive generations pair up to play finitely repeated prisoners’ dilemmas. Players observe play in previous generations and use Bayes’ rule to update their prior, π, that the world is good. We show that, if the world is really bad, then π falls per generation on average. Thus, if δ is small, there is less cooperation if the world is good, but cooperation may become more stable. For a representative 19 period repeated prisoners’ dilemma, beliefs fall one percentage point on average after a thousand generations.To derive these learning rates, we must refine existing results on the sensitivity of repeated games to Kreps et al. (1982) type perturbations. Specifically, we show cooperation is possible in perturbed prisoners’ dilemmas repeated O(log(1/δ)) times. This improves significantly on the O(1/δ) results in previous work. The paper thus provides two new reasons why cooperation tends to be stable, even in short horizon repeated games.     

Endogenous private information structures

We formally incorporate the option to gather information into a game and thus endogenize the information structure. We ask whether models with exogenous information structures are robust with respect to this endogenization. Any Nash equilibrium of the game with information acquisition induces a Nash equilibrium in the corresponding game with an exogenous structure. We provide sufficient conditions on the structure of the game for which this remains true when ‘Nash’ is replaced by ‘sequential’. We characterize the (sequential) Nash equilibria of games with exogenous information structures that can arise as a (sequential) Nash equilibrium of games with endogenous information acquisition.     

Non-marketed options, non-existence of equilibria, and non-linear prices

This paper presents a surprising example that shows that the lattice theoretic properties in Mas-Colell's (1986) seminal work are relevant to the existence of equilibrium even when the commodity space is finite dimensional.The example is a two-period securities model with a three-dimensional portfolio space and two traders. The paper identifies a non-marketed call option that fails to have a minimum cost super-replicating portfolio. Using this option, we construct an economy that satisfies all of Mas-Colell's assumptions, except that the three-dimensional commodity space is not a vector lattice. In this economy, there is no Walrasian equilibrium and the second theorem of welfare economics fails.Our example has important finite- as well as infinite-dimensional implications. It is also an example of a “well behaved” economy in which optimal allocations that are not supported by linear Walrasian prices are decentralized by the non-linear prices studied in Aliprantis-Tourky-Yannelis (2001).     

Buyer search and price dispersion: a laboratory study

We study markets with costly buyer search in which sellers simultaneously post prices. Buyers costlessly observe one or (with probability 1−q) two of the posted prices, and can accept one or pay to search again. The experiment varies q, the search cost, and the number of buyers. Equilibrium theory predicts a unified very low (high) price for q=0 (q=1) and predicts specific distributions of dispersed prices for q=1/3 and 2/3. Actual prices conform closely to the predictions in some treatments. Buyers’ reservation prices are biased away from the extremes, however, and sellers’ prices have positive autocorrelation and cross-sectional correlation.     

Outside options: Another reason to choose the first-price auction

In this paper we study equilibrium and experimental bidding behaviour in first-price and second-price auctions with outside options.We find that bidders do respond to outside options and to variations of common knowledge about competitors’ outside options. However, overbidding in first-price auctions is significantly higher with outside options than without. First-price auctions yield more revenue than second-price auctions. This revenue-premium is significantly higher with outside options. In second-price auctions the introduction of outside options has only a small effect.     

The impact of disembodied technological progress on unemployment

This paper studies the relationship between disembodied technological progress and unemployment in a standard search-matching model. We find that the sign of the correlation crucially depends on the degree of idiosyncratic uncertainty. The analysis uncovers a new effect whereby an increase in growth intensifies the endogenous rate of job separation because it raises the workers' outside option. For plausible parameter values, the outside option effect outweighs the capitalization effect, so that disembodied technological progress increases the rate of unemployment.     

Merger negotiations and ex-post regret

We consider a setting in which two potential merger partners each possess private information pertaining both to the profitability of the merged entity and to stand-alone profits, and we investigate the extent to which this private information makes ex-post regret an unavoidable phenomenon in merger negotiations. To this end, we consider ex-post incentive compatible mechanisms, which use both players' reports to determine whether or not a merger will take place and what each player will earn in each case. When the outside option of at least one player is known, the efficient merger decision can be implemented by such a mechanism under plausible budget-balance requirements. When neither outside option is known, we show that the potential for regret-free implementation is much more limited, unless the budget balance condition is relaxed to permit money-burning in the case of false reports.     

Groups, collective decisions and markets

We consider a general equilibrium model where multi-member households make efficient collective consumption decisions and operate in a competitive market environment. Individuals have the option to leave the household and make it on their own or join another household. We study the effect of these outside options on household formation, household stability and equilibrium existence.     

Motives for sharing in social networks

What motivates people in rural villages to share? We first elicit a baseline level of sharing using a standard, anonymous dictator game. Then using variants of the dictator game that allow for either revealing the dictator's identity or allowing the dictator to choose the recipient, we attribute variation in sharing to three different motives. The first of these, directed altruism, is related to preferences, while the remaining two are incentive-related (sanctions and reciprocity). We observe high average levels of sharing in our baseline treatment, while variation across individuals depends importantly on the incentive-related motives. Finally, variation in measured reciprocity within the experiment predicts observed ‘real-world’ gift-giving, while other motives measured in the experiment do not predict behavior outside the experiment.     

General equilibrium models of monopolistic competition: A new approach

We analyze a class of ‘large group’ Chamberlinian monopolistic competition models by applying different concepts of functional separability to the same set of first-order conditions for utility maximization. We show that multiplicatively quasi-separable (MQS) functions yield ‘constant relative risk aversion’ (CRRA), and, therefore ‘constant elasticity of substitution’ (CES), functions, whereas additively quasi-separable (AQS) functions yield ‘constant absolute risk aversion’ (CARA) functions. We then show that the CARA specification sheds new light on: (i) pro-competitive effects, i.e., profit-maximizing prices are decreasing in the mass of competing firms; and (ii) a competitive limit, i.e., profit-maximizing prices converge to marginal costs when the mass of competing firms becomes arbitrarily large.     

Mechanism design with multidimensional, continuous types and interdependent valuations

We consider the mechanism design problem when agents’ types are multidimensional and continuous, and their valuations are interdependent. If there are at least three agents whose types satisfy a weak correlation condition, then for any decision rule and any ?>0 there exist balanced transfers that render truthful revelation a Bayesian ?-equilibrium. A slightly stronger correlation condition ensures that there exist balanced transfers that induce a Bayesian Nash equilibrium in which agents’ strategies are nearly truthful.     

Selling options

Contracts often take the form of options: oil fields can be abandoned, planning permission may go unused, and acquired firms can be liquidated. We consider a seller who auctions a dynamic option among N agents. After the auction, the economy evolves and the winning bidder chooses both if and when to execute the option. The revenue-maximising auction consists of an up-front bid and a contingent fee, where the latter is chosen in a Pigouvian manner, so the winning agent's choice of exercise time maximises the seller's revenue. This contingent payment is time- and state-invariant, so the seller does not have to observe post-auction information in order to implement the optimal auction. The revenue-maximising mechanism induces a dynamic distortion: the option is exercised later than under the comparable welfare-maximising mechanism.     

Scenarios and creativity: Thinking in new boxes

To be creative and make change happen, leaders must do more than simply ‘think outside the box’, as the traditional business manuals suggest, using the popular American expression. After all, the space outside the box is infinitely expansive. Moreover, there can be no guarantee that a solution to the problem will be found. The answer: ‘Think in new boxes.’ This requires developing the right new box; in other words, useful new models, a helpful new approach to a problem. That is the real art of practical creativity. This short article outlines the approach (Thinking in New Boxes) and its application to classic scenario planning with a few examples. The authors also present the ‘Expressway to Scenarios’, an approach that wins in impact and practicality what it loses in deep analysis, by having top executives involved in key steps.     

Speed and quality of collective decision making: Imperfect information processing

This paper studies efficient programmed hierarchies as introduced by Radner [The organization of decentralized information processing, Econometrica 61(5) (1993) 1109-1146] in which agents cannot process information perfectly. A group of P identical managers has to make a choice between n alternatives. In order to learn which is the best option, the alternatives have to be compared. The evaluation of an alternative takes time and managers are only able to identify the better one of two alternatives with a positive probability. The skip-level reporting tree proposed by Radner is found to be efficient in terms of the dimensions decision cost, decision delay, and decision quality.     

Group decision-making in the shadow of disagreement

A model of group decision-making is studied, in which one of two alternatives must be chosen. While agents differ in their preferences over alternatives, everybody prefers agreement to disagreement. Our model is distinguished by three features: private information regarding valuations, differing intensities in preferences, and the option to declare neutrality to avoid disagreement. There is always an equilibrium in which the majority is more aggressive in pushing its alternative, thus enforcing their will via both numbers and voice. However, under general conditions an aggressive minority equilibrium inevitably makes an appearance, provided that the group is large enough. Such equilibria invariably display a “tyranny of the minority”: the increased aggression of the minority always outweighs their smaller number, leading to the minority outcome being implemented with larger probability than the majority alternative. We fully characterize the asymptotic behavior of this model as group size becomes large, and show that all equilibria must converge to one of three possible limit outcomes.