Endogenous public policy and multiple equilibria

One of the well known roles of public policy in models with indeterminacy is to reduce the set of equilibria. However, agents' expectations regarding future policy may be self fulfilling when public policy is endogenized. We show that a simple overlapping generations economy with public education may yield multiple equilibria. Under a laissez-faire system, our model has a unique equilibrium. Thus, the presence of public policy may generate, rather than eliminate, multiple equilibria.     

The role of warnings in regulation: keeping control with less punishment

Regulatory agencies frequently present violators with warnings, not pursuing prosecution if the violation ceases upon receipt of the warning. We show how such warnings may help regulators to keep control: Prosecution is costly for the regulator, and insufficient prosecution efforts yield low penalties. Thus, with a limited regulatory budget, threats of harsh sanctions are credible only if the number of violators is low. This produces multiple Nash equilibria. If firms may make mistakes, the economy can accidentally switch from one equilibrium to another. Warnings reduce substantially the probability of such accidental switches from the full-compliance to the no-compliance equilibrium.     

Type interaction models and the rule of six

In this paper, I describe and analyze a class of type interaction models. In these models, an infinite population of agents with discrete types interact in groups of fixed size and possibly change their types as a function of those interactions. I then derive conditions for these models to produce multiple equilibria. These conditions demonstrate a trade off between the number of types and the size of the interacting groups. For deterministic interaction rules, I derive the rule of six: the number of agent types plus the group size must be at least six in order to support multiple equilibria given a spanning assumption.Troy Tassier provided help with early versions of this model. Ken Arrow, Bob Axelrod, Larry Blume, Steven Durlauf, David Harris, John Holland, Lu Hong, Mercedes Pascual, Rick Riolo, and Carl Simon provided input on earlier drafts of this research. Financial support from the National Science Foundation, the James S. McDonnell Foundation and the John D. and Catherine T. MacArthur Foundation is gratefully acknowledged.     

Multiple equilibria and hysteresis in simple exchange models

This paper presents a simple two-good general equilibrium model of exchange in which demands are linear functions of relative prices. The solution of the model is represented by a cubic equation which can have either a single root which corresponds to a unique equilibrium price or three roots corresponding to multiple equilibria. The major properties of the model are that the relative price can make large discrete jumps in response to small parameter changes, and can display hysteresis. The paper shows how recent developments in non-linear methods can be used to examine the equilibrium properties of the model and establish conditions under which multiple equilibria can arise. The model is compared with that used by Shapley and Shubik.     

时滞产品生产的经济增长与社会福利分析

时滞产品生产所带来的负外部性 ,使厂商利益与社会利益往往不一致 ,时滞产品的生产导致经济增长率与社会福利的同步下降 ,并可能引致资本向时滞产品生产领域流动从而加剧其影响程度。在生产领域适当的政府调控是保障经济增长目标实现与社会福利提升的必然选择。     

A note on some properties of the ESTAR model

Some properties of ESTAR models are derived. We demonstrate that these models can exhibit chaotic dynamics and multiple equilibria. We show that a nonchaotic deterministic model with added noise can produce a time series that (falsely) appears to be chaotic.     

Evaluating currency crises: the case of the European monetary system

In this paper we examine the nature of currency crises. We ascertain whether the currency crises of the European Monetary System (EMS) were based either on fundamentals, or on self-fulfilling market expectations driven by extrinsic uncertainty. In particular, we extend previous work of Jeanne and Masson (J Int Econ 50:327–350, 2000) regarding the evaluation of currency crisis. We contribute to the existing literature proposing the use of Markov regime-switching with time-varying transition probability model. Our empirical results suggest that the currency crises of the EMS were not due only to market expectations driven by external uncertainty, or ‘sunspots’, but also to fundamental variables that help to explain the behavior of market expectations. We would like to thank Joseph Byrne, James Mitchell, Martin Weale and two anonymous referees for very useful comments and suggestions.     

Knightian uncertainty and poverty trap in a model of economic growth

This paper explores how Knightian uncertainty affects dynamic properties in an economic growth model. The decision-making theory employed in the analysis is the theory of expected utility under a non-additive probability measure, i.e., the Choquet expected utility model of preference. We apply this decision-making theory to an overlapping generations model where producers face “uncertainty” in their technologies. When the producer is averse to uncertainty, the firm's profit function may not be differentiable. Therefore, the firm's decision to invest and hire labor becomes rigid for a certain measurable range of real interest rates. In dynamic equilibrium, the existence of firm-level rigidity causes discontinuity in the wage function; this makes multiple equilibria the more likely outcomes under the log utility and Cobb–Douglas production functions. In this paper, we show that even if aversion to uncertainty is small, the “poverty trap” can arise for a wide range of parameter values.     

Public capital, endogenous growth, and endogenous fluctuations

Cazzavillan [Cazzavillan, G., 1996. Public spending, endogenous growth, and endogenous fluctuations. Journal of Economic Theory 71, 394–415] studies a discrete-time, one-sector endogenous growth model with a flow of publicly enjoyable goods and productive services financed through income taxation. He demonstrates how equilibrium paths are indeterminate, for a large range of the consumption externality of public spending. This study extends [Cazzavillan, 1996] by considering an otherwise identical production function, except with public capital stock as an input. The results support the robustness of multiple growth paths even in a one-sector growth model with public capital stock, and modify the set of the consumption externality of public spending, in determining growth dynamics in a similar model with non-accumulated public spending.     

De Finetti meets Ellsberg

The paper outlines an exchangeable non-Bayesian model of preference generalizing the Savage/de Finetti classic model of subjective expected utility preference with an exchangeable prior. The treatment is informal, and the emphasis is on motivation and potential applications rather than on axiomatic foundations and technical details. The objective is to provide a widely accessible introduction to research that is reported in detail elsewhere.     

Rich Nations, Poor Nations: How Much Can Multiple Equilibria Explain?

This paper asks whether the income gap between rich and poor nations can be explained by multiple equilibria. We explore the quantitative implications of a simple two-sector general equilibrium model that gives rise to multiplicity, and calibrate the model for 127 countries. Under the assumptions of the model, around a quarter of the world’s economies are found to be in a low output equilibrium. We also find that, since the output gains associated with an equilibrium switch are sizeable, the model can explain between 15 and 25% of the variation in the logarithm of GDP per worker across countries.     

Multiple equilibria, coordination, and transitional growth

We study a small open economy with two sectors and two factors of production. In one of the sectors, external economies of scale are generated through the industry-level capital input. This leads to a divergence between private and social production possibility frontiers as well as to multiple equilibria. The equilibrium selection problem that arises is solved by agents who follow a simple trial-and-error learning rule. The growth path of the economy as agents learn lies below the production possibility frontier and may display cyclical transitional dynamics. We also show that coordination problems which may prevent the economy from attaining the “good” equilibrium may be alleviated by the temporary use of policy instruments that shape the allocation of resources.     

Social interaction and children's academic test scores: Evidence from the National Child Development Study

We explore the relationship between educational attainment and social interaction using individual level data from the British National Child Development Study. To be specific, we analyze whether an intergenerational aspect to this relationship exists by examining the relationship between the educational attainment of children and the degree of formal social activity undertaken by their parents. Our results suggest that children's scores in reading, mathematics and vocabulary tests are positively associated with the extent of their parents’ formal social interaction, and this relationship is robust to alternative definitions of social interaction.     

Non-convex aggregate technology and optimal economic growth

This paper examines a model of optimal growth where the aggregation of two separate well behaved and concave production technologies exhibits a basic non-convexity. First, we consider the case of strictly concave utility function: when the discount rate is either low enough or high enough, there will be one steady state toward which the convergence of the optimal path is monotone and asymptotic. When the discount rate is in some intermediate range, we will find sufficient conditions for having either one equilibrium or multiple equilibria steady state. Depending to whether the initial capital per capita is located with respect to a critical value, we show that the optimal paths monotonically converge to one single appropriate equilibrium steady state. Second, we consider the case of linear utility and provide sufficient conditions to have either unique or two steady states when the discount rate is in some intermediate range. In this range, we give conditions under which the above critical value might not exist, and the economy attains one steady state in finite time, then stays at the other steady state afterward. P. Michel passed away when this research was completed. This paper is dedicated to his memory as a friend and colleague. N. M. Hung and C. Le Van thank the referee for vey helpful remarks and criticisms. They are grateful to Takashi Kamihigashi for very fruitful discussions. They also thank J.-F. Leclerc for editing the final version of this paper.     

Regional debt in monetary unions: Is it inflationary?

This paper studies the inflationary implications of interest bearing regional debt in a monetary union. Is this debt simply backed by future taxation with no inflationary consequences? Or will the circulation of region debt induce monetization by a central bank?We argue here that both outcomes can arise in equilibrium. In the model economy, there are multiple equilibria which reflect the perceptions of agents regarding the manner in which the debt obligations will be met. In one equilibrium, termed Ricardian, the future obligations are met with taxation by a regional government while in the other, termed Monetization, the central bank is induced to print money to finance the region's obligations. The multiplicity of equilibria reflects a commitment problem of the central bank. A key indicator of the selected equilibrium is the distribution of regional debt holdings. We show that regional governments, anticipating central bank financing of their debt obligations, have an incentive to create excessively large deficits. We use the model to assess the impact of some policy measures within a monetary union as well as dollarization.     

Endogenous technological change with leisure-dependent utility

Summary. This paper investigates the effect of introducing leisure-dependent utility into two models of endogenous technological change. Due to the flexibility in the labour supply the dynamics of the models change significantly. It is shown that if agents attach enough value to leisure in comparison to consumption two balanced growth paths may exist. This implies that economies with the same preferences and the same technology may experience different long-run growth rates. Received: October 17, 1997; revised version: January 6, 1999