Time Consistent Optimal Redistribution Policy in an Overlapping Generations Model

This paper analyzes optimal redistribution policy in a two‐period version of the overlapping generations model with heterogeneous individuals and asymmetric information between the government and the private sector. The government of the first period determines redistribution transfers for the first period but is not able to set the policy variables for the second period. With respect to savings the paper considers two scenarios: In the first scenario savings are observable and the government can set individual savings levels in addition to redistributive transfers. In the second scenario savings and capital incomes are not observable. In both cases the redistribution equilibrium is not second‐best efficient.     

Optimal growth in the two-sector neoclassical growth model

This article analyzes optimal growth in the neoclassical two-sector model. First, the optimal savings ratio is derived corresponding to that growth path which maximizes consumption at each point of time. Secondly, it can be shown that this optimal savings ratio is the limit for the optimal savings ratio as derived by Pontryagin's maximum principle for an optimal policy, when the social discount rate for future per capita consumption approaches zero.This work was supported by the Deutsche Forschungsgemeinschaft, West-Germany.     

Social Comparisons and Optimal Taxation in a Small Open Economy

In this paper, we analyze how international capital mobility affects the optimal labor and capital income tax policy in a small open economy when consumers care about relative consumption. The main results crucially depend on whether the government can tax returns on savings abroad. If the government can use flexible residence‐based capital income taxes, then the optimal policy rules from a closed economy largely carry over to the case of a small open economy. If it cannot, then capital income taxes become completely ineffective. The labor income taxes must then indirectly also reflect the corrective purpose that the absent capital income tax would have had.     

Consumption externalities with endogenous time preference

This paper shows that in a model with inelastic labor supply, consumption externalities have impacts on stationary consumption and capital. The key element in observing the effects of consumption externalities on stationary consumption and capital is the endogeneity of the time preference rate, which depends on future-oriented resources rather than on private consumption. We conclude that when individuals experience jealousy, they become more impatient, leading to a lower level of capital stock and a higher level of consumption relative to those of the social optimum, while when they experience admiration, these relationships are reversed. We examine an optimal tax policy that replicates the socially optimal path in the centrally planned economy. Finally, using numerical analysis we explore how this economy evolves through time.      

Consumption adaptation,anticipation‐bias,and optimal income taxation

Adaptation is omnipresent but people systematically fail to correctly anticipate the degree to which they adapt, leading them to make irrational intertemporal decisions. This paper concerns optimal income taxation to correct for such anticipation‐biases in a framework where consumers adapt to earlier consumption levels. The analysis is based on a general equilibrium OLG model with endogenous labor supply and savings where each consumer lives for three periods. The results show how a paternalistic government may correct for the effects of anticipation‐bias through a combination of time‐variant marginal labor income taxes and savings subsidies/taxes. The optimal policy mix remains the same, irrespective of whether consumers commit to their original life time plan for work hours and consumption or reoptimize later on when realizing that they have already adapted more than expected.     

Welfare effects of automatic-IRAs

Several states require employers who do not offer retirement benefits to automatically enroll their employees in individual retirement accounts (IRAs). We quantify the welfare effects of this program for individuals who follow a rule-of-thumb to make savings decisions. We find workers who save more than 3% would be willing to give up 0%–1.4% of lifetime consumption to avoid an IRA. We also consider a fully rational model with credit frictions, stochastic income and pre-retirement withdrawals, and costly IRA opt-outs. We find that being enrolled in an IRA is most likely to benefit workers who do not borrow during the life-cycle.     

Capital Tax Competition and Cooperation with Endogenous Capital Formation

Incorporating consumption–savings choices under a general concave utility function and hence an endogenous capital supply into a model of capital tax competition, we re‐investigate Nash equilibrium and compare it with the optimum under cooperative tax policy. In contrast to the case of fixed capital supply, it is shown that if savings sufficiently increase with the interest rate, a Nash equilibrium may be more efficient than a cooperative tax policy. Therefore, the distortionary effects of capital supply are important to issues of tax policy coordination.     

The Leontief Two-sector Model and Undiscounted Optimal Growth with Irreversible Investment: The Case of Labor-intensive Consumption Goods

This essay reports results on optimal growth in a Leontief two-sector model originally formulated by Bruno and analyzed in discrete time by Nishimura-Yano. Applying geometric methods pioneered by Khan-Mitra, we derive a complete characterization of optimal policy. Assuming that the consumption goods sector is more labor-intensive, our results depart from those in the capital-intensive case: (i) every optimal program is monotonic, (ii) every optimal program converges to the golden-rule stock in a finite number of periods, and (iii) every optimal program undergoes either unemployment or excess capacity of capital.     

ENDOGENOUS BUSINESS CYCLES: THE INFLUENCE OF CHARACTER TRAITS*

This article deals with how business cycles can occur, in light of character traits which influence individual behaviour in an economy. We assume an overlapping generations model in which every consumer has identical instantaneous utility which is additively separable with respect to time. The parameters of utility here include character traits which influence the choice between consumption and savings. In this situation, young individuals choose between current consumption and current savings which lead to future consumption in their old age. Individual character traits, which appear both in the shape of utility functions and in evaluations about utility in the future, affect these choices. And since these choices determine savings, individual character traits can eventually determine how our economy moves. Focusing on the relationship between individual character traits and savings formation, we demonstrate that endogenous business cycles with two periods can occur, in an economy comprised of individuals who opt for current consumption and who are careless in relation to future events, like Aesopian grasshoppers, and in other cases they do not.     

Loss aversion and social security: a general equilibrium approach

Introducing an intertemporal model of loss aversion, I study the role of social security in determining intergenerational redistribution when consumers have reference-dependent preferences with loss aversion. Using a unified social security model in which different social security plans are specified via different degrees of fundedness, I examine the effect of the transition from a less funded system to a more funded one on savings, consumption, and capital accumulation for an OLG production economy. A general equilibrium analysis shows that the direction of intertemporal equilibrium is dependent on how the total savings responds to the interest rate change, but the effect of the payroll tax on capital accumulation is ambiguous. By deriving closed-form solutions, I find that an increase in fundedness intensity unambiguously increases capital accumulation in steady states, while the tax effects on consumption and savings are not conclusive. Moreover, simulation exercises show that when consumers are prone to over-consume because they care more about the contemporaneous gain utility, the fully funded system may help the individuals smooth out their lifecycle consumption.     

Rationalizing multiple consumption-saving puzzles in a unified framework

Empirical evidence suggests that it may cost time, effort, and resources to implement an optimal consumption-saving plan, although the cost may differ across individuals. This paper explores the implications of such friction. We begin by documenting a series of facts on consumption and savings over the life cycle, each of which goes against the prediction of the standard life-cycle model. While the existing studies demonstrate how various permutations of the benchmark model may help resolve one or another of these puzzles, it appears difficult to jointly rationalize even a small subset of these facts within the existing theories. We then incorporate a feature of costly implementation into the benchmark model and show that the addition of this one feature moves in the right direction in jointly resolving all these puzzles. This friction is the sole and common mechanism in our model for rationalizing this series of facts, as we intentionally abstract from the mechanisms explored in the existing literature that are known to help explain one or another of these facts, in order to isolate the role of costly implementation. The implementation costs in the model are small, yet our results show that the mechanism can be important in complementing the existing theories to help account for these consumption and saving facts in a unified framework.     

Stochastic growth with correlated production shocks

This paper extends the stochastic growth model of Brock and Mirman [J. Econ. Theory4 (1972), 497–513] to allow the production shocks to be correlated over time. The resultant optimal savings and consumption policies depend not only upon the current level of output but also upon the most recent realization of the random shock. The properties of these policy functions are studied and it is shown that the Markov process on output, capital stock and consumption resulting from the application of these policies converges to a stationary distribution.     

Optimal time paths with age-dependence: a theory of population policy

A mathematical model is established whereby optimal accumulation paths of population and the economy can be figured when the basic feature of population dynamics, age dependence, is taken into account. This model series links 2 previously separate disciplines and literatures - i.e., formal policy dealing with the dynamics of age and time. An integral-equation control theory is utilized. Recognition of age structure in analyzing fertility trends is important at both macro- and microeconomic levels. The present model was constructed by embedding an age-disaggregated population in a simple economic growth model where the fertility level and rate of savings can both be influenced by government policy. Such policy should balance the lifetime value of births and capital against the social costs necessary to create them. One the problem has been defined and a dynamic theory developed, optimum static theories can be establihsed where the variables are held constant over time.     

Rational inattention,long-run consumption risk,and portfolio choice

This paper explores how the introduction of rational inattention (RI) – that agents process information subject to finite channel capacity – affects optimal consumption and investment decisions in an otherwise standard intertemporal model of portfolio choice. We first explicitly derive optimal consumption and portfolio rules under RI and then show that introducing RI reduces the optimal share of savings invested in the risky asset because inattentive investors face greater long-run consumption risk. We also show that the investment horizon matters for portfolio allocation in the presence of RI, even if investment opportunities are constant and the utility function of investors is constant relative risk aversion. Second, after aggregating across investors, we show that introducing RI can better explain the observed joint dynamics of aggregate consumption and the equity return. Finally, we show that RI increases the implied equity premium because investors under RI face greater long-run consumption risk and thus require higher compensation in equilibrium.     

Lifetime vs Annual Tax-Transfer Incidence: How Much Less Progressive?

Annual fiscal incidence studies have found that income taxes and cash transfers are highly progressive and that their net effect is to redistribute income from rich to poor. Yet many argue Jhat such studies overstate the redistribution achieved by governments and that lifetime analysis is needed New results suggest that both income taxes and cash transfers are progressive on a lifetime basis, although they are much less progressive than annual studies suggest. The Australian tax-transfer system thus generates some lifetime redistribution from rich to poor, while also enforcing intra-personal redistribution across the life cycle of individuals.     

收入不平等、政策偏向与最优财政再分配政策

本文构建的理论模型探讨了收入不平等、政策偏向与最优财政再分配之间的关系。模型显示:政策偏向是收入不平等与财政再分配恶性循环的决定因素。当政策偏向于穷人时,最优财政再分配系统的选择是提高税率,扩大对穷人的转移支付;当政策偏向于富人时,最优财政再分配系统的选择是降低税率,减少对穷人的转移支付。依据中国数据的实证研究发现:(1)中国收入不平等不断恶化,针对恶化的不平等而采取的财政再分配政策效果差,没能扭转不平等恶化趋势,政策偏向严重。(2)税收再分配政策偏向富人,使富人税负相对轻于穷人,居民收入不平等加剧;偏向于穷人的转移支付多为消费券(物),导致越扶越贫。为此,需要从调整所得税和转移支付政策等方面采取相关对策。     

Pollution and life expectancy: How environmental policy can promote growth

This article investigates the influence of environmental policy (EP) on growth in an AK-type growth model, when finite lifetime is introduced and the link between pollution and life expectancy (through the detrimental impact of pollution on health) is taken into account.Using an overlapping generations model à la Blanchard [Blanchard, O. (1985). Debt, deficits and finite horizon. Journal of Political Economy, 93:223-247], we demonstrate that finite lifetime introduces a “generational turnover effect” which modifies the influence of the EP on growth. Thus, when lifetime is finite and independent from pollution, we show that the “generational turnover effect” limits the detrimental impact of the EP on growth, if agents smooth their consumption over time. When pollution negatively influences life expectancy through health, we demonstrate that the “generational turnover effect” is magnified and that the EP and growth have an inverted U-shaped relationship in the steady-state. In this case, we show that the environmental policy is more likely to promote growth (i.e. it stimulates growth for a wider range of environmental taxes) when the impact of pollution on health is important and/or public expenditures in health are low. Finally, using numerical simulations, we find that for the value of parameters that we have chosen, the EP will be more likely to promote growth when agents smooth consumption over time.     

Optimal unemployment insurance: transitional dynamics vs. steady state

In this study, we ask whether the presence of precautionary savings substantially reduces the optimal replacement rate in an European economy type characterized by high unemployment benefits and moral hazard. We build a simple job search model calibrated on French data and, in line with previous studies, find that the optimality criterion based on comparisons of steady states leads to a low optimal ratio. Yet, this result ignores potential transitional costs due to the necessity for agents to increase their savings and reduce their consumption whenever the ratio is cut. We therefore build a dynamic model taking full account of the transition, and show that a reduction in benefits reduces welfare. Even though the long-run optimal replacement rate is lower than the current one, transitional costs dominate long-run gains.     

Landfill Construction and Capacity Expansion

We study the optimal capacity and lifetime of landfills taking into account their sequential nature. Such an optimal capacity is characterized by the so-called Optimal Capacity Condition. Particular versions of this condition are obtained for two alternative settings: first, if all the landfills are to have the same capacity, and second, if each of them is allowed to have a different capacity. In the second case we obtain an optimal control problem, with mixed elements of both continuous and discrete time. The resulting optimization problems involve dividing a time horizon of planning into several subintervals of endogenously decided length. The results obtained may be useful to address other economic problems such as private and public investments, consumption decisions on durable goods, etc.     

Optimal monetary policy in a Phillips-curve world

In this paper, we study optimal monetary policy in a model that integrates the modern theory of unemployment with a liquidity model of monetary transmission. Two policy environments are considered: period-by-period optimization (time consistency) and full commitment (Ramsey allocation). When the economy is subject to productivity shocks, the optimal policy is pro-cyclical. We also characterize the long-term properties of monetary policy and show that with commitment the optimal inflation rate is inversely related to the bargaining power of workers. Both results find empirical support in the data.