A note on contribution games with loss functions

Decisions on joint funding of continuous public goods between two agents often involve heterogeneous targets. We introduce loss functions in a contribution game in order to study the effect of this conflict. Unlike Varian (1994), joint contribution occurs only if the players’ targets are sufficiently close and the sequential game reduces free riding problems, while total contribution is higher in the simultaneous game.     

MIMICKING THE WINNER LEADS TO WAR: AN EVOLUTIONARY ANALYSIS OF CONFLICT AND COOPERATION*

This note applies an evolutionary analysis to Skaperdas's (1992) static model of conflict and cooperation, in which agents are faced with trade‐offs between joint production and share competition. We adopt the stochastic evolution approach, and assume that each agent occasionally mimics the action of the winner of the stage. In contrast to Skaperdas's results that justify full or partial cooperation in productive activity, the long‐run equilibrium must exhibit total conflict; nobody engages in production at all.     

A Theory of Civil Conflict and Democracy in Rentier States*

The effects of resource rents on the political equilibrium have been studied in two main types of models. The first tradition uses models of conflict, and studies how resource rents affect the intensity and duration of civil conflict. The second tradition uses political economy models, where resource rents affect the political equilibrium due to changes in the costs and benefits of buying votes. Although they provide considerable insight, these traditions have little to say about when democracy emerges, and about when conflict emerges. In this paper, by integrating the earlier model traditions, we suggest the simplest possible framework we can think of to study the choice between conflict and democracy. We show how factors such as resource rents, the extent of electoral competition, and productivity affect economic and political equilibria.     

Core equivalence with congested public goods

Summary This paper examines a model of an infinite production economy with a finite number of types of agents andsemi- public goods, which are subjected to crowding and exclusion. The utility of an agent depends not only on the vector of public commodities produced by the coalition to which she belongs, but also on the mass of agents of her type who are the members of this coalition. The main purpose of the paper is to derive necessary and sufficient conditions on the local degrees of congestion which would guarantee the equivalence between the core and the set of equal treatment Lindahl equilibria. We prove that this equivalence holdsif and only if there are constant returns to group size for each type of agents. It implies that linearity of each agent's congestion function with respect to the mass of the agents of her own type is necessary for the core equivalence to hold.The final version of this paper was written while Shlomo Weber was visiting the Technical University of Dresden as the Fellow of the Alexander von Humboldt Foundation, whose support is gratefully acknowledged. The authors are grateful to Peter Meyer, Nicholas Yannelis and the anonymous referees for useful remarks and suggestions.     

Informational size and incentive compatibility with aggregate uncertainty

In McLean and Postlewaite (Econometrica 56, 1992, p. 2421), we analyzed pure exchange economies with asymmetrically informed agents. We defined a notion of informational size and showed that, when the aggregate information of all agents resolves nearly all the uncertainty regarding the state of nature, the conflict between incentive compatibility and (ex post) efficiency can be made small if agents have sufficiently small informational size. This paper investigates the relationship between informational size and efficiency for the case in which nontrivial aggregate uncertainty is present, i.e., when significant uncertainty about the world persists even when the information of all agents is known.     

Informational smallness and the scope for limiting information rents

For an incomplete-information model of public-good provision with interim participation constraints, we show that efficient outcomes can be approximated, with approximately full surplus extraction, when there are many agents and each agent is informationally small. The result holds even if agents' payoffs cannot be unambiguously inferred from their beliefs. The contrary result of Neeman [Z. Neeman, The relevance of private information in mechanism design, J. Econ. Theory 117 (2004) 55-77] rests on an implicit uniformity requirement that is incompatible with the notion that agents are informationally small because there are many other agents who have information about them.     

War, peace, and the size of countries

This paper studies the relationship between international conflict and the size distribution of countries in a model in which both peaceful bargaining and nonpeaceful confrontations are possible. We show how the size distribution of countries depends on the likelihood, benefits, and costs of conflict and war. We also study the role of international law and show how better defined international ‘property rights’ may lead to country breakup and more numerous local conflicts.     

An endogenous policy model of hierarchical government

Endogenous policy models usually neglect that government policies are frequently the result of decisions taken at different tiers by different agents, each enjoying some degree of autonomy. In this paper, policies are the outcome of the choices made by two agents within a hierarchy. A legislator decides on the budget to be successively spent by a bureaucrat. Both agents are lobbied by one or two interest groups. The combination of sequential decisionmaking and lobbying implies that the interaction between the agent at one tier and the interest group(s) depends on the exchange between the same interest group(s) and the agent at the other tier. Our results concerning multi-tier lobbying and legislatorial oversight substantially qualify the conventional wisdom related to one-tier lobbying. In particular, the reaction of the legislator to lobbying at the bureaucratic tier may make lobbying wasteful even when there is no competition from other lobbies. Moreover, the legislator benefits from lobbying only when there is competition between interest groups at the upper tier. It is also shown that competition for influence at the bureaucratic tier may work as a perfect substitute for legislatorial oversight. Extensions of the model indicate its usefulness for the analysis of decisionmaking in other multilevel governance structures, like federations or firms.     

Nonseparable preferences and optimal social security systems

In this paper, we consider economies in which agents are privately informed about their skills, which evolve stochastically over time. We require agents' preferences to be weakly separable between the lifetime paths of consumption and labor. However, we allow for intertemporal nonseparabilities in preferences like habit formation. In this environment, we derive a generalized version of the Inverse Euler Equation and use it to show that intertemporal wedges characterizing optimal allocations of consumption can be strictly negative. We also show that preference nonseparabilities imply that optimal differentiable asset income taxes are necessarily retrospective in nature. We show that under weak conditions, it is possible to implement a socially optimal allocation using a social security system in which taxes on wealth are linear, and taxes/transfers are history-dependent only at retirement. The average asset income tax in this system is zero.     

Aiding violence or peace? The impact of foreign aid on the risk of civil conflict in sub-Saharan Africa

This paper considers the impact of foreign aid flows on the risk of civil conflict. We improve on earlier studies on this topic by addressing the problem of the endogenous aid allocation using GDP levels of donor countries as instruments. A more structural addition to the literature is that we efficiently control for unobserved country specific effects in typical conflict onset and conflict continuation models by first differencing. The literature often overlooks the dynamic nature of these types of models, thereby forcing unlikely i.i.d. structures on the error terms implicitly.¹ As a consequence, malfunctioning institutions, deep-rooted political grievances, or any other obvious, yet unobserved and time persistent determinants of war are simply assumed away. We find a statistically significant and economically important negative effect of foreign aid flows on the probability of ongoing civil conflicts to continue (the continuation probability), such that increasing aid flows tends to decrease civil conflict duration. We do not find a significant relationship between aid flows and the probability of civil conflicts to start (the onset probability).     

The strategy-proof provision of public goods under congestion and crowding preferences

We examine the strategy-proof provision of excludable public goods when agents care about the number of other consumers. We show that strategy-proof and efficient social choice functions satisfying an outsider independence condition must always assign a fixed number of consumers, regardless of individual desires to participate. A hierarchical rule selects participants and a generalized median rule selects the level of the public good. Under heterogeneity in agents’ views on the optimal number of consumers, strategy-proof, efficient, and outsider independent social choice functions are much more limited and in an important case must be dictatorial.     

Social Conflict and Gradual Political Succession: An Illustrative Model*

This paper studies the evolution of political institutions in the face of conflict. We examine institutional reform in a class of pivotal mechanisms—institutions that behave as if the resulting policy were determined by a “pivotal” decision maker drawn from the potential population of citizens and who holds full policy‐making authority at the time. A rule‐of‐succession describes the process by which pivotal decision makers in period t + 1 are, themselves, chosen by pivotal decision makers in period t. Two sources of conflict—class conflict, arising from differences in wealth, and ideological conflict, arising from differences in preferences—are examined. In each case, we characterize the unique Markov‐perfect equilibrium of the associated dynamic political game, and show that public decision‐making authority evolves monotonically downward in wealth and upward in ideological predisposition toward the public good. We then examine rules‐of‐succession when ideology and wealth exhibit correlation.     

Informational externalities with lump-sum sampling

Abstract .  We consider a game of strategic experimentation where agents are restricted to an all-or-nothing sampling strategy. The strategic interaction between agents due to informational externalities is affected by the sizes of the experimentation samples and the sensitivity of information to changes in sample sizes. There is experimentation only if the overall sample is large enough. Equilibrium may involve optimal, insufficient or excessive experimentation relative to a second-best welfare benchmark. This unusual over-experimentation result is associated not necessarily with large samples but with a low elasticity of the value of information with respect to the sample size.     

On the robustness of laissez-faire

This paper considers a model economy in which agents are privately informed about their type: their endowments of various goods and their preferences over these goods. While preference orderings over observable choices are allowed to be correlated with an agent's private type, we assume that the planner/government is both uncertain about the nature of this joint distribution and unable to choose among multiple equilibria of any given social mechanism. We model the planner/government as having a maxmin objective in the face of this uncertainty.Our main theorem is as follows: Once we allow for this kind of uncertainty and assume no wealth effects in preferences, the uniquely optimal social contract is laissez-faire, in which agents trade in unfettered markets with no government intervention of any kind.     

Collective decisions with interdependent valuations

Many collective decision problems have in common that individuals’ desired outcomes are correlated but not identical. This paper studies collective decisions with private information about desired policies. Each agent holds private information which mainly concerns his own bliss point, but private information also affects all other agents. We concentrate on two specific mechanism, the median and mean mechanisms establish the existence of symmetric Bayesian Nash equilibria of the corresponding games and compare the performance of the mechanisms for different degrees of interdependencies. Applications of our framework include the provision of public goods and the design of decision processes in international organizations.     

The effect of ambiguity aversion on reward scheme choice

We test the implications of ambiguity aversion in a principal–agent problem with multiple agents. Models of ambiguity aversion suggest that, under ambiguity, comparative compensation schemes may become more attractive than independent wage contracts. We test this by presenting agents with a choice between comparative reward schemes and independent contracts, which are designed such that under uncertainty about output distributions (that is, under ambiguity), ambiguity averse agents should typically prefer comparative reward schemes, independent of their degree of risk aversion. We indeed find that the share of agents who choose the comparative scheme is higher under ambiguity.     

Redistribution as a selection device

This paper studies the role of the wealth distribution for the market selection of entrepreneurs when agents differ in talent. It argues that the redistribution of initial endowments can increase an economy's surplus because more talented individuals get credit for their risky investment projects. Moreover, the redistribution of initial endowments may lead to a Pareto-improvement although all agents are non-satiable. An agent's entrepreneurial ability is his private information and there is moral hazard in production. I find conditions such that unproductive rich entrepreneurs crowd out productive poor ones on the capital market. Then redistribution of initial endowments may lead to a new equilibrium where market participants are better informed about the entrepreneurs’ ability. The new equilibrium is characterized by (i) the selection of better entrepreneurs, (ii) a higher riskless rate of return on capital, (iii) lower repayments of successful entrepreneurs to their creditors and (iv) the fact that all agents are better off.     

Conflict, defense spending, and the number of nations

This paper provides a formal model of endogenous border formation and choice of defense spending in a world with international conflict. We examine both the case of democratic governments and of dictatorships. The model is consistent with three observations. First, breakup of countries should follow a reduction in the likelihood of international conflicts. Second, the number of regional conflicts between smaller countries may increase as a result of the breakup of larger countries. Third, the size of the peace dividend (the reduction in defense spending in a more peaceful world) is limited by the process of country breakup.     

Group Contests with Internal Conflict and Power Asymmetry

We investigate simultaneous inter‐ and intra‐group conflict in the shadow of within‐group power asymmetry and complementarity in members' group‐conflict efforts. A more symmetric group faces a higher degree of internal conflict, and might expend more effort in external conflict when the group‐conflict effort technology is highly complementary. Depending on the degree of complementarity, the stronger player's relative contribution to external conflict might be higher in a more asymmetric group and, as a result, it is possible for the weaker player to earn a higher payoff. In the absence of any complementarity, the rent‐dissipation is non‐monotonic with the within‐group power asymmetry.     

The relevance of private information in mechanism design

Recent results in mechanism design show that as long as agents have correlated private information and are sufficiently risk neutral, it is possible to design mechanisms that leave agents with arbitrarily small information rents. We show that these full-rent-extraction results hinge on the implicit assumption that the agents’ beliefs uniquely determine their preferences. We present an example of the voluntary provision of a public good in which this assumption is relaxed, and consequently, even in highly correlated environments, if agents’ beliefs do not uniquely determine their preferences, then the extraction of the agents’ entire information rents is impossible.