A note on optimal income taxation,public goods provision and robust mechanism design

This paper extends the model of optimal income taxation due to Mirrlees (Mirrlees, J., 1971. An exploration in the theory of optimum income taxation. Review of Economic Studies 38, 175–208) and includes private information on public goods preferences. A mechanism design approach is used to establish the following result: If policies are required to be robustly implementable in the sense of Bergemann and Morris (Bergemann, D., Morris, S., 2005. Robust mechanism design. Econometrica 73, 1771–1813), then the optimality conditions in the extended model with uncertainty about tax and expenditure policies are the same as in the standard model of optimal income taxation. The paper provides a foundation for a widely-used assumption in public finance, namely that individuals optimize their behavior subject to a predetermined and commonly known tax system.     

THE WELFARE GAINS OF AGE‐RELATED OPTIMAL INCOME TAXATION

Using an overlapping generations model with skill uncertainty and private savings, we quantify the gains of age‐dependent labor income taxation. The total steady‐state welfare gain of switching from age‐independent to age‐dependent nonlinear taxation varies between 2.4% and 4% of GDP. Part of the gain descends from relaxing incentive–compatibility constraints and part is due to capital‐accumulation effects. The welfare gain is of about the same magnitude as that which can be achieved by moving from linear to nonlinear income taxation. Finally, the welfare loss from tax‐exempting interest income is negligible under an optimal age‐dependent labor income tax.     

The effect of potential emigration on the optimal linear income tax

This paper amends a standard model of optimal linear income taxation to allow individuals to escape taxation by migrating. The income tax is used only to redistribute income in this model. It is found that, if individuals with low and high ability levels are prevented from migrating, then the optimal marginal tax and poll subsidy increase. But preventing migration at ability levels in some intermediate interval lowers the optimal marginal tax.     

Labor supply,uncertainty, and efficient taxation

We analyze the structure of an optimal linear income tax when workers are uncertain about their wages at the time they choose their labor supplies. Background for the normative analysis is provided by an outline of the positive theory of wage taxation and labor supply under uncertainty. It is then shown that given imperfect information about wages, lump-sum taxation is not necessarily efficient. Because a wage tax reduces the riskiness of wage income, some combination of a lump-sum tax and a wage tax generally will minimize excess burden.     

Optimal human capital policies under the endogenous choice of educational types

This study examines optimal human capital policies under nonlinear labor and capital income taxes in the presence of consumption value of education in a two‐period setting. We show that when individuals can choose educational types differing by the relative importance of consumption value and production value, education subsidies for low‐type individuals should not equal an efficient level that offsets distortions induced by nonlinear taxes on labor and capital income. Our findings imply that education policy does not restore efficiency, or the Diamond–Mirrlees production efficiency theorem fails. Moreover, capital income taxation is optimal, which means that the Atkinson–Stiglitz theorem breaks down.     

On Optimal Commodity Taxes When Consumption Is Time Consuming

This paper studies the problem of optimal taxation of commodities when consumption is a time‐consuming activity. This is done under two distinct preference separability assumptions: between goods and labor supply, and between goods and leisure. It argues that with the labor separability, the traditional uniform taxation results of optimal tax theory continue to hold. With leisure separability, on the other hand, consumption time is a major ingredient of optimal tax rates. However, the relationship between consumption time and optimal tax rates depends crucially on the representation of the economy. In representative consumer economies, time differences determine the pattern of optimal tax rates so that goods whose consumption take more time are subjected to higher tax rates. When individuals have different earning abilities, redistributive, incentive, and efficiency considerations also come into play resulting in a complex relationship. The paper derives formulas for optimal commodity taxes in this case on the basis of three different tax structures: linear commodity taxes in combination with linear and nonlinear income taxes, and nonlinear commodity taxes in combination with nonlinear income taxes.     

SOME EMPIRICAL EVIDENCE ON DEMAND SYSTEM* AND OPTIMAL COMMODITY TAXATION

We have two major tasks in this paper. The first is to obtain a reasonable estimate of the Japanese demand system, which includes leisure, income and commodity choices. The second is to compute and evaluate the optimal tax equilibrium. The estimation result, based on the Almost Ideal Demand System, is found to be consistent with the microeconomic theory. We evaluate the optimal commodity tax structure by calculating the equilibria under lump‐sum, optimal commodity and uniform commodity taxation schemes. The deadweight losses under uniform taxation are very small, and the optimal commodity tax rates are strikingly close to uniform.     

Optimal unemployment insurance and redistribution

We characterize optimal income taxation and unemployment insurance in a search‐matching framework where both voluntary and involuntary unemployment are endogenous and Nash bargaining determines wages. Individuals decide whether to participate as job seekers and if so, how much search effort to exert. Unemployment insurance trades off insurance versus search and participation incentives. We also allow for different productivity types so there is a redistributive role for the income tax and show that a piecewise linear wage tax internalizes the macro effects arising from endogenous wages. Type‐specific lump‐sum taxes and transfers can then redistribute between individuals of differing skills and employment states. Our analysis embeds optimal unemployment insurance into an extensive‐margin optimal redistribution framework where transfers to the involuntarily and voluntarily unemployed can differ, and nests several standard models in the literature.     

Optimal linear income taxation in the presence of emigration

This paper examines optimal linear income taxation when individuals are able to escape taxation by migrating. A model is presented in which closing the economy to migration must raise the optimal marginal tax. However, this result may be reversed under an alternative definition of a closed economy.     

Subsidies versus Public Provision of Private Goods as Instruments for Redistribution

The literatures on differential commodity taxes and on quantity controls to supplement income taxation have developed separately. This paper combines these two strands in the standard framework of optimal non-linear income taxation. We use a model with two types of households where the government has access to both subsidy policy and public provision of a good substitutable for leisure, and ouseholds can supplement the publicity provided good from the market. We present conditions under which policy should involve one or both of these two instruments alongside income taxation. The model is extended to many ability types.     

Pricing of Transport Networks,Redistribution, and Optimal Taxation

The author studies optimal pricing of roads and public transport in the presence of nonlinear income taxation. Individuals are heterogeneous in unobservable earning ability. Optimal transport tariffs depend on time costs of travel and work schedule adjustments (days and hours worked per day) as a response to commuting costs. The author finds that discounts for low‐income individuals are optimal only if the time cost of a trip is small enough. Lower travel time costs facilitate screening; therefore, redistribution provides an additional motive for congestion pricing. Finally, the study investigates the desirability of means‐testing of transport tariffs.     

Optimal Redistributive Income Taxation and Efficiency Wages*

In this paper, we integrate efficiency wage setting with the theory of optimal redistributive income taxation. In doing so, we use a model with two skill types, where efficiency wage setting characterizes the labor market faced by the low‐skilled, whereas the high‐skilled face a conventional, competitive labor market. We show that the marginal income tax implemented for the high‐skilled is negative under plausible assumptions. The marginal income tax facing the low‐skilled can be either positive or negative, in general. An increase in unemployment benefits contributes to a relaxation of the binding self‐selection constraint, which makes this instrument particularly useful from the perspective of redistribution.     

Viewpoint: Innovations in the theory and practice of redistribution policy

Abstract We present a survey of key results from second‐best optimal redistribution theory and their implications for tax‐transfer policy. The core results include the Corlett‐Hague theorem, the Deaton conditions, the production‐efficiency theorem, the Atkinson‐Stiglitz theorem, and the Mirrlees‐Saez characterization of the optimal non‐linear income tax system. These have been augmented in recent years by optimal participation tax rates, the implications of involuntary unemployment, the use of unconventional instruments, such as minimum wages, in‐kind transfer, and workfare, and the optimal taxation of capital income and bequests.     

Optimum taxation with errors in administration

The paper compares the welfare levels which can be achieved by two distinct tax regimes: lump-sum taxation, where one attempts to identify individuals and allocate transfers or subsidies on the basis of characteristics, and income taxation, where characteristics are not observed but personal incomes are measured and taxed. Where there are no errors in classifying individuals, lump-sum taxation is superior, but, where mistakes are made in the allocation of lump-sum grants or subsidies, income taxation may be more attractive. The level of errors where the regimes are equally desirable in terms of social welfare is computed in simple models following that of Feldstein (1973). Where there is strong aversion to inequality, then income taxation becomes preferable at quite small errors.In analysing income taxation it is shown that in the Feldstein model with endogenous wages the marginal tax rate (in optimum income taxation) on the more skilled is negative and that on the less skilled is positive in contrast to the standard results [see Seade (1977)] with exogenous wages.     

Jointly Optimal Taxes and Enforcement Policies in Response to Tax Evasion

Assuming the government cannot fully observe either individual types or incomes and jointly picks optimal taxes and audit policies against evasion can significantly alter standard results from optimal income taxation and tax‐evasion models, which treat these separately. We consider this when individuals differ in their risk preferences and incomes. Given the resulting complexity, supplementing analytic results with numerical analysis helps explain the structure of the resulting policies and how they change when the distribution of income or the revenue requirements of the government change. We do this analysis with and without audit errors and with incomes exogenous or affected by occupational choice.     

Optimal Income Taxation with Endogenous Human Capital

This paper augments the theory of optimal linear income taxation by taking into account human capital accumulation as a dimension of labor supply. The distribution of earning potentials is endogenous because agents differ in the ability to learn. Taxation affects utilization rates of human capital through labor supply responses. The costs of education that are not deductible from the income tax distort the learning decision as well. We show theoretically that the trade‐off between efficiency and equity is worsened. Quantitative analysis shows that the distortionary costs of taxation increase substantially when human capital formation is endogenous.     

Taxation of capital income in overlapping generations economies

Whether capital income should be taxed in overlapping generations economies is vividly discussed. It is shown that intergenerational lump‐sum taxes cannot implement the Golden Rule allocation when agents have private information on their earnings potential. Hence, the seminal Atkinson–Stiglitz result that optimal income taxation pre‐empts any role for indirect taxation cannot be interpreted to imply that capital income taxation (affecting intertemporal relative prices) should not be taxed. Specifically, capital income should unambiguously be taxed in small open economies, and the optimal tax rate depends inversely on the elasticity of total savings to disposable income and the after‐tax rate of return.     

POSITIONAL CONCERNS IN AN OLG MODEL: OPTIMAL LABOR AND CAPITAL INCOME TAXATION*

This article concerns optimal income taxation under asymmetric information in a two‐type OLG model when individuals’ relative consumption matters. Positional concerns affect the policy choices via two channels: (i) the average degree of positionality and (ii) positionality differences between the low‐ability type and the mimicker. Under plausible empirical estimates, the marginal labor income tax rates become substantially larger, and the absolute value of the marginal capital income tax rate of the low‐ability type becomes substantially smaller, than in the conventional model. In addition to measures of reference consumption based on average consumption, we also address within‐generation and upward comparisons.     

Public Investment and Income Taxation: Redistribution vs. Productive Performance

This paper deals with government investment in a static two-type self-selection model of optimum income taxation. It is shown that the second-best investment rule is consistent with efficient production, provided that public investment has no influence on relative factor prices. Otherwise, however, redistributive income taxation implies that optimal investment expenditures exceed (or fall below) the efficient level as long as they raise (or decrease) the wage rate of the unskilled individuals relative to the wage rate of the skilled individuals.     

Optimal Income Taxation with Risky Earnings: A Synthesis

We study optimal nonlinear income taxation when earnings can differ because of both ability and luck, so the income tax has both a redistributive role and an insurance role. A substantial literature on optimal redistribution in the absence of risk has evolved since Mirrlees's original contribution. The literature on the income tax as a social insurance device is more limited. It has largely assumed that households are ex ante identical so unequal earnings are due to risk alone. We provide a general treatment of the optimal income tax under risk when households differ in ability. We characterize optimal marginal tax rates and interpret them in terms of redistribution, insurance, and incentive effects. The case of ex ante identical households and the no‐risk case with heterogeneous abilities come out as special cases.