On the optimal income taxation and educational decisions

In this paper we consider three different ways of incorporating individuals' educational choices into the design of optimal income tax policy. In one variant of the model (case 2), where an individual chooses his education before knowing his ability and after that education makes his labour supply decisions on the basis of known ability, it is shown that qualitative features of the optimal income tax schedule are not similar to those of the standard optimal income tax model. The marginal tax rate is generally not zero at the endpoints of distribution but is most likely negative. Using numerical methods, some interesting features quite different from earlier numerical results are revealed, especially in the second case. For example, the marginal tax rate is non-decreasing in income for a substantial income range. In addition, our calculations support neither the traditional views on the egalitarian nature of equal education nor its disadvantageous consequences in the perfect utilitarian society.     

On the undesirability of commodity taxation even when income taxation is not optimal

An important result due to Atkinson and Stiglitz (1976) [Atkinson, A.B., Stiglitz, J.E., 1976. The design of tax structure: Direct versus indirect taxation. Journal of Public Economics 6, 55–75.] is that differential commodity taxation is not optimal in the presence of an optimal nonlinear income tax (given weak separability of utility between labor and all consumption goods). This article demonstrates that this conclusion holds regardless of whether the income tax is optimal. In particular, given any commodity tax and income tax system, differential commodity taxation can be eliminated in a manner that results in a Pareto improvement. Also, differential commodity taxation can be proportionally reduced so as to generate a Pareto improvement. In addition, for commodity tax reforms that neither eliminate nor proportionally reduce differential taxation, a simple efficiency condition is offered for determining whether a Pareto improvement is possible.     

RELATIVITY,INEQUALITY, AND OPTIMAL NONLINEAR INCOME TAXATION

How does concern for consumption relative to others (“relativity”) affect the structure of optimal nonlinear income taxation? Our article provides three sets of answers to this general question. First, it supports the conclusion in the literature that relativity leads to higher marginal tax rates. In doing so, it both generalizes some of the conditions under which this result is obtained in the literature and fleshes out the detailed structure for optimal marginal tax rates for specific functional forms for distribution, utility function, and social welfare function. Second, the article goes beyond the literature and examines the impact of relativity on the progression of optimal marginal tax rates. By and large, we find support for greater progressivity, defined as the steepness of the rise of the marginal tax rate schedule, as relativity concern increases. Third, none of the papers in the literature, to our knowledge, examines the interplay of relativity and inequality in determining the optimal structure of income taxes. Our special analytical cases and more general numerical calculations support the conclusion that higher inequality dampens the positive impact of greater relativity on the level and the progression of marginal tax rates. More work is needed to further explore this interaction between relativity and inequality that our analysis has uncovered.     

Optimal top marginal tax rates under income splitting for couples

This paper provides formulas for optimal top marginal tax rates when couples are taxed according to income splitting between spouses, consumption is taxed, and the skill distribution is unbounded. Optimal top marginal income tax rates are computed for Germany using a dataset that includes the tax returns of all German top taxpayers. We find that the optimal top marginal tax rate converges to about 2/3 and convergence obtains at income levels that are substantially higher than those currently subject to the actual top tax rate.     

Redistributive taxation as social insurance

The modern literature on nonlinear optimal taxation treats differences in income as being due to unobserved differences in ability. A striking result of this assumption is that high income agents should face a zero marginal tax rate. In this paper I assume that differences in observed income are due to exogenous differences in luck. Hence the optimal redistributive tax involves trading off the benefits due to ‘social insurance’ with the costs due to reduced incentives. I derive the optimal forms for linear and nonlinear taxes, and compute some algebraic and numeric examples. Typically high income individuals will face quite high marginal tax rates.     

Optimal Nonlinear Income Taxation with Habit Formation

It has recently been shown that incorporating “keeping up with the Joneses” preferences into a prototypical two‐ability‐type optimal nonlinear income tax model leads to higher marginal tax rates for both types of agents. In particular, the high‐skill type faces a positive marginal tax rate, rather than zero as in the conventional case. In this paper, agents’ utility functions are postulated to exhibit “habit formation in consumption” such that the prototypical two‐ability‐type optimal nonlinear income tax model becomes a dynamic analytical framework. We show that if the government can commit to its future fiscal policy, the presence of consumption habits does not affect the standard results on optimal marginal tax rates. By contrast, if the government cannot precommit, the high‐skill type will face a negative marginal tax rate, while the low‐skill type’s marginal tax rate remains positive.     

The optimal linear income tax revisited

This paper shows that the Mirrlees-Seade conditions of agent monotonicity and noninferiority of leisure imply the positivity of the optimal marginal income tax rate in Sheshinski's model of linear income taxation as well as in the general model. The optimal marginal tax rate is bounded above by the Rawlsian rate, which in turn is bounded by the revenue-maximizing rate. The optimal marginal tax rate may be arbitrarily close to the Rawlsian rate. However, the optimal marginal tax rate is bounded away from the revenue-maximizing rate whenever the individual with the lowest ability works.     

The marginal utility of income

In normative public economics it is crucial to know how fast the marginal utility of income declines as income increases. One needs this parameter for cost-benefit analysis, for optimal taxation and for the (Atkinson) measurement of inequality. We estimate this parameter using four large cross-sectional surveys of subjective happiness and two panel surveys. Altogether, the data cover over 50 countries and time periods between 1972 and 2005. In each of the six very different surveys, using a number of assumptions, we are able to estimate the elasticity of marginal utility with respect to income. We obtain very similar results from each survey. The highest (absolute) value is 1.34 and the lowest is 1.19, with a combined estimate of 1.26. The results are also very similar for subgroups in the population. Thus, on the basis of our estimates, the marginal utility of income declines somewhat faster than in proportion to the rise in income.     

Production Efficiency and the Direct-Indirect Tax Mix

In the design of the optimal direct/indirect tax mix, the canonical view was laid by Atkinson and Stiglitz (1976) who showed that commodity taxes are unnecessary in an economy in which there is an optimal nonlinear income tax provided that commodities are separable from labor in the utility functions of all taxpayers, that the aggregators over these commodities are ordinally equivalent and that wages are fixed. When wages are endogenous, Naito (1999) showed that this result may not hold and in addition that production efficiency may not be Pareto optimal. Given an optimal nonlinear income tax, we show that production inefficiency is Pareto optimal if the aggregate technology set is strictly concave. The Atkinson–Stiglitz condition is neither necessary nor sufficient for zero commodity taxation and commodity taxes are part of almost all Pareto optima.     

Poverty alleviation and tax policy

This paper examines public good provision and tax policy—optimal non-linear income taxation and linear commodity taxation—when the government departs from purely welfarist objective function and seeks to minimise poverty. This assumption reflects much policy discussion and may help understand some divergences of practical tax policy from lessons in optimal tax analysis. In contrast to Atkinson and Stiglitz (J. Public Econom. 6 (1976) 55), it may be optimal to use differentiated commodity tax rates, including the taxation of savings, even if preferences are separable in goods and leisure. The optimal effective marginal tax rate at the bottom of the distribution may be negative, suggesting that wage subsidy schemes can be optimal. Finally, optimal provision of a public good is analysed under poverty minimisation.     

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.     

Self-selection and Pareto efficient taxation

This paper analyses the set of Pareto efficient tax structures. The formulation of the problem as one of self-selection not only shows more clearly the similarity between this problem and a number of other problems (such as the optimal pricing of a monopolist) which have recently been the subject of extensive research, but also allows the derivation of a number of new results. We establish (i) under fairly weak conditions, randomization of tax structures is desirable; (ii) if different individuals are not perfect substitutes for one another in production, then the general equilibrium effects—until now largely ignored in the literature—of changes in the tax structure may be dominant in determining the optimal tax structure; in particular if the relative wage of high ability and low ability individuals depends on the relative supplies of labor, the optimal tax structure entails a negative marginal tax rate on the high ability individuals, and a positive marginal tax rate on the low ability individuals (the marnitude of which depends on the elasticity of substitution); (iii) if individuals differ in their preferences, Pareto efficient taxation may entail negative marginal tax rates for high incomes; while (iv) if wage income is stochastic, the marginal tax rate at the upper end may be 100%.Our analysis thus makes clear that the main qualitative properties of the optimal tax structure to which earlier studies called attention are not robust to these attempts to make the theory more realistic.     

Optimal income taxation with a stationarity constraint in a dynamic stochastic economy

We consider the optimal nonlinear income taxation problem in a dynamic, stochastic environment when the government cannot change the tax rule as uncertainty resolves. Due to such a stationarity constraint, our taxation problem is reduced to a static one over an expanded type space that incorporates type evolution. We strengthen the argument in the static model that the zero top marginal tax rate result is of little practical importance because it only applies to the top of the expanded type space. If the maximal type increases over time, the person with top ability in any period but the last has a positive marginal tax rate.     

Imperfect Tax Compliance and the Optimal Provision of Public Goods

Our aim in this paper is to investigate whether the presence of imperfect income tax compliance affects the optimal provision of public goods within a framework in which public expenditure is financed by a general income tax that also accomplishes redistributive goals. We first derive the income tax structure, and then a generalized Samuelson rule. We argue that, under imperfect income tax compliance, it is desirable to distort public–good supply downwards, in the sense that the sum of marginal rates of substitution between public and private consumption must exceed their marginal rate of transformation.     

The Optimal Linear Income Tax Model: Utility or Equivalent Income?

This paper compares the use of equivalent income with that of utility, in the social welfare function, in optimal income tax models. Equivalent income is a money metric welfare measure that, unlike utility, is not affected by monotonic transformations of utility. The use of equivalent income is found to produce an optimal tax rate that is more sensitive to the degree of inequality aversion, compared with the use of utility. With Cobb-Douglas and CES utility functions, the optimal tax rate is the same for utility and equivalent income where relative inequality aversion is unity. When using equivalent incomes, the case for high marginal rates does not depend on the assumption of a very low elasticity of substitution between consumption and leisure.     

The Optimal Asymptotic Income Tax Rate

This paper shows that a policy maker needs only two types of information to set the optimal income tax rate at the top: a measure of labor supply elasticity and the shape of skills distribution. We find that the asymptotic tax rate is not affected by the degree of inequality aversion as long as the marginal utility of consumption converges to zero. By using empirically plausible estimates for the compensated labor supply elasticity and the shape of skills distribution, we find that the optimal marginal tax rate at the top should be between 33% and 60%, which is in line with the existing rates in the real world.     

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.     

Optimal mixed taxation,credit constraints,and the timing of income tax reporting

We study optimal income and commodity tax policy with credit‐constrained low‐income households. Workers receive an even flow of income during the tax year, but report their incomes and make tax payments (receive transfers) at the end of the year. They spend their disposable income on multiple commodities over the year. We show that differentiated subsidies on commodities can be optimal even if the Atkinson–Stiglitz Theorem conditions apply. When the optimal policy leaves low‐income households with binding credit constraints, it may be optimal to subsidize differentially the good that they consume in higher proportion. Uniform subsidies would also relax the credit constraint, but would be more costly to the government since they would equally benefit unconstrained households. Numerical examples suggest that commodity tax differentiation increases with basic needs and with the interest rate at which government borrows.     

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.