Dynamic contracting with persistent shocks

In this paper, we develop continuous-time methods for solving dynamic principal-agent problems in which the agent's privately observed productivity shocks are persistent over time. We characterize the optimal contract as the solution to a system of ordinary differential equations and show that, under this contract, the agent's utility converges to its lower bound—immiserization occurs. Unlike under risk-neutrality, the wedge between the marginal rate of transformation and a low-productivity agent's marginal rate of substitution between consumption and leisure will not vanish permanently at her first high-productivity report; also, the wedge increases with the duration of a low-productivity report. We apply the methods to numerically solve the Mirrleesian dynamic taxation model, and find that the wedge is significantly larger than that in the independently and identically distributed (i.i.d.) shock case.     

CAPITAL MAINTENANCE AS A KEY DEVELOPMENT TOOL

We construct optimal growth models where labor resources can be allocated either to production, technology adoption or capital maintenance. We first characterize the balanced growth paths of a benchmark model without maintenance. Then we introduce maintenance activity via the depreciation rate of capital. We characterize the optimal allocation of labor across the three activities. Although maintenance deepens the technological gap by diverting labor resources from adoption, we show that it generally increases the long run output level. Moreover, we find that equilibrium maintenance and adoption efforts respond in opposite directions to policy or technology shocks. Finally, we find that the long‐term output response to policy shocks is slightly higher in the presence of maintenance.     

Optimal age‐dependent income taxation in a dynamic extensive model: The case for negative participation tax on young people

We consider optimal age‐dependent income taxation in a dynamic model where the labor‐leisure choice is the extensive margin, each household faces idiosyncratic shocks to labor productivity and a pecuniary cost to work, and there is no insurance market against the shocks. We show that the well‐known property of the optimal participation tax rate in the static model continues to hold in our dynamic economy, that is, the participation tax rates for some income groups with low consumption are likely negative. In dynamic models, the optimal participation tax rate depends on age and on labor income. Our numerical simulations suggest that a negative participation tax should be restricted to young households.     

The quest for status and endogenous labor supply: the relative wealth framework

We analyze the implications of relative wealth preferences in a Ramsey model with endogenous labor supply. In contrast to relative consumption preferences, they allow for the possibility that agents work too little in the long run, while under both specifications the steady-state levels of consumption and the stock of physical capital exceed their socially optimal counterparts. Even in the case of excessive leisure agents are worse off in terms of intertemporal utility because initial transitional dynamics are characterized by under-consumption and excessive work effort. “Too much” long-run consumption of goods and leisure is possible due to the excessive capital-labor ratio.      

CONSUMPTION AND LEISURE EXTERNALITIES, ECONOMIC GROWTH AND EQUILIBRIUM EFFICIENCY

This paper analyzes the effects of consumption and leisure externalities on growth and welfare in a two‐sector endogenous growth model with human capital accumulation. Both types of externalities are shown to affect the long‐run equilibrium and optimal growth rates in a rather different way. The relationship between the steady state of the market and the centrally planned economy is also analyzed. The optimal growth path can be decentralized by resorting to consumption or labor income taxation, whereas capital income should be untaxed. Numerical simulations suggest that growth and welfare effects of mild consumption and leisure externalities may be quantitatively important.     

The optimality of nominal contracts

Summary. This paper presents a model in which agents choose to use money as a medium of exchange, a means of payment, and a unit of account. The paper defines conditions under which nominal contracts, promising future payment of a fixed number of units of fiat money, prove to be the optimal contract form in the presence of either relative or aggregate price risk. When relative prices are random, nominal contracts are optimal if individuals have ex ante similar preferences over future consumption. When the aggregate price level is random, whether from shocks to the money supply or aggregate output, nominal contracts (perhaps coupled with equity contracts) lead to optimal risk-sharing if individuals have the same degree of relative risk aversion. Finally, nominal contracts may be optimal if the repayment of contracts is subject to a binding cash-in-advance constraint. In this case, a contingent contract increases the risk of holding excessive cash balances. Received: March 29, 1996; revised version: February 25, 1997     

Industry equilibrium with random exit or default

An industry consisting of a large number of small price taking firms subject to idiosyncratic productivity shocks is considered. At the moment of entry, a firm takes on debt. We show that in a competitive equilibrium, some firms exit and pay out their debt while others choose to default. The outcome depends on the realization of firm‐specific shocks. The paper demonstrates that if the firms self‐select between exit with debt repayment and default, then the default region is disconnected from the exit region. The methodological contribution of the paper is the analytical characterization of the long‐run equilibrium for two scenarios of the initial distribution of productivity shocks. We consider two public policy mechanisms—contract enforcement and creditor protection. Our policy recommendation is that regulators need to reduce the contract enforcement if they want to decrease the long‐run default rate.     

Consumption smoothing in Russia1

Using a panel from the Russian Longitudinal Monitoring Survey (1994–2004), this paper investigates to what extent Russian households have been able to maintain their living standards while suffering income shocks. Consumption smoothing is modelled by means of an equilibrium correction mechanism, which disentangles short‐run dynamics and long‐run equilibrium adjustments. GMM estimation is used to control for individual household effects in the presence of dynamics. Additionally, we differentiate between food and non‐food consumption, positive and negative shocks, rural and urban areas, and several levels of poverty risk. We find that dynamics are important in the consumption equation, and that estimates are sensitive to imputation errors in home food production. No strong claims can be made regarding heterogeneity in smoothing behaviour.     

HUMAN CAPITAL ACCUMULATION,HOME PRODUCTION AND EQUILIBRIUM DYNAMICS*

In this paper, we construct a three‐sector endogenous growth model in which long‐run growth is propelled by human capital accumulation. We show that although the addition of a home sector to the standard two‐sector endogenous growth model preserves the well‐behaved balanced growth equilibrium properties, it generates new transitional dynamics around the balanced growth path. It is shown that, when there is a positive shock to physical capital, our model is more likely to exhibit paradoxical growth than are standard multisector endogenous growth models that exclude home production. Our analysis adds new results to those from the related literature on leisure.     

Sources of Fluctuations in the Real Exchange Rates and Trade Balances of the G‐7: A Sign Restriction VAR Approach

This paper estimates structural vector autoregression models of output, the real exchange rate and trade balance for the group of seven leading advanced economies (G‐7). Unlike previous studies, we do not impose long‐run purchasing power parity as an identifying assumption; instead, the shocks underlying the model are structurally identified using a set of theory‐consistent sign restrictions. Empirical results show that nominal shocks account for most of the long‐run variability in trade balances across the G‐7 countries. We are able to attribute this finding to long‐run movements in the real exchange rate, as the real exchange rate is significantly affected by nominal shocks in the long run.     

Population growth: A pure welfarist approach

In this study we propose a framework based on welfarist principles to deal with several issues concerned with population economics models, such as the Repugnant Conclusion, both in absolute and relative sense, the shape of childbearing costs and population dynamics, under both normative and positive perspectives. We show that the relative critical level criterion can avoid both the assumption of high childbearing costs and the absolute repugnant conclusion (ARC) but cannot avoid the relative repugnant conclusion (RRC). Moreover, optimal fertility is increased by technological shocks and displays cycles. Both ARC and RRC can be avoided by extending the model to a decentralized economy with consumption externalities; in the latter model, a technological shock reduces long‐run fertility and can generate cycles along the transitional path.     

Growth effects of environmental policy when pollution affects health

In this paper, we develop a R&D-based growth model with a pollution externality and a health production sector. We study how health-impairing pollution affects long term growth, and the effect of an emissions' reduction policy (tax). We show that a tighter environmental tax has positive effects on growth via two channels. On the one hand, it improves workers' health and, thereby, productivity; on the other hand, it induces a reallocation of resources towards R&D and, thereby, higher research intensity. The size of the growth effect of a tighter environmental tax, and the level of the optimal environmental tax, are both positively correlated with the weight individuals place on health relative to consumption. As for welfare, a tighter environmental tax brings about utility gains in the long run and, potentially, also in the short run.     

Implications of Endogenous Group Formation for Efficient Risk-Sharing

The existing literature on sub-game perfect risk-sharing suffers from a basic inconsistency. While a group of size n is able to coordinate on a risk-sharing outcome, it is assumed that deviating subgroups cannot. I relax this assumption and characterise the optimal contract among all coalition-proof history-dependent contracts. This alters the predictions of the standard dynamic limited commitment model. I show that the consumption of constrained agents depends on both the history of shocks and its interaction with the current income of other constrained agents. From this, I derive a formal test for the presence of endogenous group formation under limited commitment.     

Can Habit Formation Be Reconciled with Business Cycle Facts?

Many asset pricing puzzles can be explained when habit formation is added to standard preferences. We show that utility functions with a habit then gives rise to a puzzle of consumption volatility in place of the asset pricing puzzles when agents can choose consumption and labor optimally in response to more fundamental shocks. We show that the consumption reaction to technology shocks is too small by an order of magnitude when a utility includes a consumption habit. Moreover, once a habit in leisure is included, labor input is counterfactually smooth over the cycle. In the case of habits in both consumption and leisure, labor input is even countercyclical. Consumption continues to be too smooth. Journal of Economic Literature Classification Numbers: E13, E21, E32.     

Non-neutral responses to money supply shocks when consumption and leisure are Pareto substitutes

Summary. To a greater extent than is often stressed in existing literature, preference assumptions affect responses to money shocks in equilibrium monetary models. Temporary money shocks can have persistent real effects if the marginal utility of leisure is a decreasing function of consumption, where leisure is measured as time endowment less market labor effort, and consumption refers to market produced goods. This condition is an empirically supported implication of home production models. Though not theoretically necessary for supporting the existence of short run real effects, the presence of distortionary taxes and endogenous productivity can have significant quantitative effects on responses to temporary money supply shocks. Received: August 21, 1996; revised version: February 3, 1997     

Do Firms Provide Wage Insurance against Shocks?

Implicit contract models imply that it is Pareto optimal for risk‐neutral firms to provide insurance to risk‐averse workers against shocks. Using a matched employer–employee dataset, I evaluate wage responses to both permanent and transitory shocks in Hungary, and compare my results to similar studies on Italian, Portuguese, German, and French datasets. I find that the magnitude of the wage response differs depending on the nature of the shock. Broadly speaking, the wage response to permanent shocks is twice the size of the response to transitory shocks. Unlike previous findings, my results show that full insurance against transitory shocks is rejected.     

Government Expenditure Financing in a Two‐Sector Cash‐In‐Advance Model of Endogenous Growth

We show that an expansion in the government size could be desirable from the viewpoint of the economy's long‐run growth, wherein factor intensity between the sectors, the mode of public spending financing, and the form of the cash‐in‐advance (CIA) constraint are crucial. We also show that when real balances are required only for consumption purchases, money financing is equivalent to consumption tax financing, but is not equivalent to income tax financing. If both consumption and gross investment are liquidity‐constrained, then the three financing methods are mutually not equivalent. The optimal financing scheme has the following features: (1) when the CIA constraint applies only to consumption purchases, any combination of the money growth rate and the consumption tax rate that satisfies the government budget constraint constitutes an optimal financing mix; (2) when the CIA constraint applies to both consumption and investment purchases, consumption tax financing only is optimal.     

Sustained positive consumption in a model of stochastic growth: The role of risk aversion

In a stochastic economy, long run consumption and output may not be bounded away from zero even when productivity is arbitrarily high near zero and uncertainty is arbitrarily small. In the one-sector stochastic optimal growth model with i.i.d. production shocks, we characterize the nature of preferences that lead to this phenomenon for a stochastic Cobb–Douglas technology. For the general version of the model, we outline sufficient conditions under which the economy expands its capital stock near zero and long run consumption is bounded away from zero with certainty. Our conditions highlight the important role played by risk aversion for small consumption levels.     

Modelling the demand for housing over the life cycle

We model individual demand for housing over the life cycle, and show the aggregate implications of this behaviour. Individuals delay purchasing their first home when incomes are low or uncertain. Higher house prices lead households to downsize, rather than to stop being owners. Fixed costs (property transactions taxes) have important impacts on welfare (a wealth effect) and house purchase decisions (substitution effect). In aggregate, positive house price shocks lead to consumption booms among the old but falls in consumption for the young, and reduced housing demand; positive income shocks lead to consumption booms among the young and increased housing demand.     

Optimal Redistribution with Endogenous Social Norms

In this paper, we examine the effect of social norms on redistributive policies, where social norms are reflected in the degree of work participation among the different skill classes. Participation is driven both by the material incentives and heterogeneous preferences for leisure of each skill class, and by an endogenous social norm. Results for optimal redistributive taxation show that when the social norm enters as a benefit or cost for participants, participation taxes are generally lower than in its absence. Multiple participation equilibria can occur, and an engineered shift from a low‐ to a high‐participation equilibrium can be Pareto‐improving in the long run.