Knowledge that Transforms

We endogenize preferences using the “indirect evolutionary approach”. Individuals are randomly matched to play a two-person game. Individual (subjective) preferences determine their behaviour and may differ from the actual (objective) pay-offs that determine fitness. Matched individuals may observe the opponents’ preferences perfectly, not at all, or with some in-between probability. When preferences are observable, a stable outcome must be efficient. When they are not observable, a stable outcome must be a Nash equilibrium and all strict equilibria are stable. We show that, for pure-strategy outcomes, these conclusions are robust to allowing almost perfect, and almost no, observability, with the notable exception that inefficient strict equilibria may fail to be stable with any arbitrarily small degree of observability (despite being stable with no observability).

We study coalition formation in “real time”, a situation in which coalition formation is intertwined with the ongoing receipt of pay-offs. Agreements are assumed to be permanently binding: They can only be altered with the full consent of existing signatories. For characteristic function games we prove that equilibrium processes—whether or not these are history dependent—must converge to efficient absorbing states. For three-player games with externalities each player has enough veto power that a general efficiency result can be established. However, there exist four-player games in which all Markov equilibria are inefficient from every initial condition, despite the ability to write permanently binding agreements.

This paper analyses a dynamic auction in which a fraction of each bid is sunk. Jump bidding is used by bidders to signal their private information. Bluffing (respectively sandbagging) occurs when a weak (respectively strong) player seeks to deceive his opponent into thinking that he is strong (respectively weak). A player with a moderate valuation bluffs by making a high bid and drops out if his bluff is called. A player with a high valuation should vary his bids and should sometimes sandbag by bidding low, to induce lower bids by his rival.

The paper studies a model in which in period 1, a decision-maker chooses a set of lotteries; and in period 2, Nature chooses a lottery from the set chosen by the decision-maker and the decision-maker consumes the lottery chosen by Nature. Larger sets are interpreted as representing more ambiguous objective information about the lottery that will be consumed. The axioms imposed on preferences over sets of lotteries generalize those often imposed on preferences over single lotteries in the existing literature. A decision-maker who satisfies these axioms evaluates sets of lotteries according to a weighted average of the expected utilities of the best and the worst lottery in a set, with the weights interpreted as a measure of (comparative) attitude to objective ambiguity. ∗I am grateful to Walter Bossert and Peter Klibanoff for their remarks and suggestions regarding related literature. The paper has been presented at Northwestern University, Princeton University,

This paper shows how standard arguments supporting the imposition of price caps break down in the presence of demand uncertainty. In particular, though in the deterministic case the introduction or lowering of a price cap (above marginal cost) results in increased production, increased total welfare, decreased prices, and increased consumer welfare, we show that all of the above comparative statics predictions fail for generic uncertain demand functions. For example, for price caps sufficiently close to marginal cost, a decrease in the price cap always leads to a decrease in production and total welfare under certain mild conditions. Under stronger regularity assumptions, all of the monotone comparative statics predictions from the deterministic case also do not hold for a generic uncertain demand if we restrict attention to price caps in an arbitrary fixed interval (as long as the price caps are binding for some values in that interval).

In contrast to domestic trade, international trade inherently requires more intensive use of skilled labour with expertise in areas such as international business, language skills, and maritime insurance, and the transoceanic transportation is more capital intensive than the local transportation. In the presence of such bias in factor demands, globalization caused by an improvement in the export technologies can lead to a worldwide increase in the relative prices of the factors used intensively in international trade. Furthermore, a worldwide increase in the factors used intensively in international trade can lead to globalization. To capture these effects, we develop a flexible approach to model costly international trade, which includes the standard iceberg approach as a special case. More specifically, we extend the Ricardian model of trade with a continuum of goods by introducing multiple factors of production and by making technologies of supplying goods depend on whether the destination is home or abroad. If the technologies of supplying the same good to the two destinations differ only in total factor productivity, the model becomes isomorphic to the Ricardian model with the iceberg cost. By allowing the two technologies to differ in the factor intensities, our approach enables us to examine the links between factor endowments, factor prices, and globalization that cannot be captured by the iceberg approach. Copyright 2007, Wiley-Blackwell.

This paper shows how particle filtering facilitates likelihood-based inference in dynamic macroeconomic models. The economies can be non-linear and/or non-normal. We describe how to use the output from the particle filter to estimate the structural parameters of the model, those characterizing preferences and technology, and to compare different economies. Both tasks can be implemented from either a classical or a Bayesian perspective. We illustrate the technique by estimating a business cycle model with investment-specific technological change, preference shocks, and stochastic volatility.

We present identification and estimation results for the “collective” model of labour supply in which there are discrete choices, censoring of hours, and non-participation in employment. We derive the collective restrictions on labour supply functions and contrast them with restrictions implied by the usual “unitary” framework. Using the large changes in the wage structure between men and women in the U.K. over the last two decades, we estimate a collective labour supply model for married couples without children. The estimates of the sharing rule show that male wages and employment have a strong influence on bargaining power within couples.

Much of the existing literature on social security has taken the extreme assumption that individuals have little or no altruism; this paper takes an opposite assumption that there is full two-sided altruism. When households insure members that belong to the same family line, privatizing social security can gain public support. In our benchmark model calibrated to the U.S. economy, privatization without compensation is favoured by 52% of the population. If social security participants are fully compensated for their contributions, and the transition to privatization is financed by a combination of debt and a consumption tax, 58% experience a welfare gain. These gains and the resulting public support for social security reform depend critically on a flexible labour market. If the labour supply elasticity is low, then support for privatization disappears. Copyright 2007, Wiley-Blackwell.

In this paper I show that an equilibrium exists to the sequential voting game in which a bandwagon begins with probability 1. These bandwagons are driven by a combination of beliefs and the desire of voters to vote for the winning candidate. Significantly, in this equilibrium the pivot probability for each voter is non-zero, even in an infinite population. Consequently, the bandwagons do not always start after one (or at most two) favourable decisions (as do economic cascades) and varying levels of informative voting are observed, consistent with observations from sequential voting in U.S. presidential primaries. Further, voters are exposed to counterintuitive incentives, referred to as “buyers' remorse”, that have been attributed to real primary voters. I also derive equilibrium behaviour in this environment when voting is simultaneous and compare the quality of information aggregation within each mechanism. I relate the conclusions to U.S. presidential primaries and find they are consistent with a common conclusion about the front-loading of the primary process: that in tight elections (with no front-runner) simultaneous voting is preferred, whereas in lopsided elections sequential voting is preferred. The superior performance of sequential voting in lopsided races is precisely because bandwagons occur.