Public investment criteria under optimal nonlinear income taxation without commitment

In this study, we highlight that the incredibility of the government's commitment to a certain tax policy is a determinant of production inefficiency. We show that if the government cannot commit to a certain tax policy and if the types of taxpayers are completely separated, then the production efficiency theorem could be violated in an optimal solution. In this case, an incremental unit of public or private capital affects taxpayers' labor supply through wage rates. In a situation where public capital is more (less) complementary to labor than private capital, public investment tightens (relaxes) the incentive compatibility constraint more than private investment.     

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 optimality of optimal income taxation

The Mirrleesian model of income taxation restricts attention to simple allocation mechanism with no strategic interdependence, i.e., the optimal labor supply of any one individual does not depend on the labor supply of others. It has been argued by Piketty (2009) [12] that this restriction is substantial because more sophisticated mechanisms can reach first-best allocations that are out of reach with simple mechanisms. In this paper, we assess the validity of Piketty?s critique in an independent private values model. As a main result, we show that the optimal sophisticated mechanism is a simple mechanism, or, equivalently, a Mirrleesian income tax system.     

Social security, retirement age and optimal income taxation

It is often argued that implicit taxation on continued activity of elderly workers is responsible for the widely observed trend towards early retirement. In a world of laissez-faire or of first-best efficiency, there would be no such implicit taxation. The point of this paper is that, when first-best redistributive instruments are not available, because some variables are not observable, the optimal policy does imply a distortion of the retirement decision. Consequently, the inducement of early retirement may be part of the optimal tax-transfer policy. We consider a model in which individuals differ in their productivity and their capacity to work long and choose both their weekly labor supply and their age of retirement. We characterize the optimal non-linear tax-transfer that maximizes a utilitarian welfare function when weekly earnings and the length of active life are observable while individuals' productivity and health status are not observable.     

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.     

Wage endogeneity,tax evasion,and optimal nonlinear income taxation

This paper studies the interaction between tax evasion and wage endogeneity within a Mirrleesian optimal tax framework. It characterizes the optimal marginal income tax rates on the skilled and the unskilled workers and the optimal amount of resources to be spent on deterring tax evasion. It shows that tax evasion weakens the incentives for the government to manipulate the marginal tax rates for the purpose of exploiting general equilibrium effects on wages. Moreover, the extent of this depends on the curvature of the evasion cost function. It also argues that marginal income tax rates are likely to be higher when the government attempts to deter evasion.     

On the optimal income taxation: Some further numerical results

Using numerical calculations we show in the optimal income tax model that a realistic value for the elasticity of substitution between consumption and leisure (?=0.5) leads to conclusions different from some of those drawn by Mirrlees (1971) and Atkinson (1973). The marginal tax rates are not so low and the shape of the tax schedule is for a great majority of the population substantially nonlinear. A new feature in our calculations is that both results come out without going to maximin, as done by Atkinson (1973). We study in special cases the locality of the zero limit of the marginal tax rate at the upper end of the ability distribution and we achieve a very definite conclusion: this result is really very local. We also present an interesting approximation result concerning the relationship between the level of the government revenue and the marginal tax rate for individuals with high ability. An important methodological remark analogous to Sen's critique on the ethical measures of inequality is made on the interpretation of optimal income tax calculations.     

A contribution to the theory of optimal utilitarian income taxation

The paper provides a new formulation of the Mirrlees–Seade theorem on the positivity of the optimal marginal income tax, under weaker assumptions and in a more general model. The formulation of the theorem is independent of whether the model involves finitely many types or a continuous type distribution. The formal argument makes the underlying logic transparent, relating the mathematics to the economics and showing precisely how each assumption enters the analysis.     

Trade,environment, and income inequality: An optimal taxation approach

In a small open economy, how should a government pursuing both environmental and redistributive objectives design domestic taxes when redistribution is costly? And how does trade liberalization affect the economy's levels of pollution and inequalities, when taxes are optimally and endogenously adjusted? Using a general equilibrium model under asymmetric information with two goods, two factors (skilled and unskilled labor), and pollution, this paper characterizes the optimal mixed tax system (nonlinear income tax and linear commodity and production taxes/subsidies) with both production and consumption externalities. While optimal income taxes are not directly affected by environmental externalities, conditions are derived under which under‐ or over‐internalization of social marginal damage is optimal for redistributive considerations. Assuming that redistribution operates in favor of the unskilled workers and that the dirty sector is intensive in unskilled labor, simulations suggest that trade liberalization involves a clear trade‐off between the reduction of inequalities and the control of pollution when the source of externality is only production; this is not necessarily true with a consumption externality. Finally, an increase in the willingness to redistribute income toward the unskilled results paradoxically in less pollution and more income inequalities.     

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.     

The optimal taxation of risky capital income: An elasticity rule

Should risky capital income be taxed like safe income or should tax rates be differentiated? The question is analyzed in a 2-assets model of portfolio choice. Flat tax rates are chosen in order to maximize the investor's expected utility from terminal wealth subject to an expected tax revenue constraint. If lump-sum taxes are not available, optimal tax rates are characterized by an elasticity rule: The relative change in the risk remuneration should be equal to the inverse of the product of two elasticities. One is the output elasticity of capital. The other is the demand elasticity for risky investments with respect to a revenue preserving tax variation.     

Subjective well‐being,consumption comparisons,and optimal income taxation

We introduce reference consumption into the standard utility function from optimal tax analysis. Individuals compare their consumption “narrowly” with those of the same productivity, or “broadly” with the average consumption across society. In both narrow and broad equilibria reference consumption is an increasing function of the tax parameters, so generating new theoretical results. Individual well‐being decreases with the net wage (net‐of‐tax) rate for low productivity workers under narrow (broad) comparisons, thus adjusting redistributive taxation considerations. Further, in both cases reference consumption distorts labor supply away from the social optimum level, giving a distortion‐correcting role for taxation.     

Public goods,taxation, and the distribution of income over time

With given fiscal and collective choice institutions, the provision and concomitant financing of a public good affect individuals' saving decisions and, hence, may affect the course of the income distribution over time. This paper focuses on this problem for the case of a constitutional democracy in which the major fiscal institution is a set of fixed tax shares and the collective choice mechanism is simple majority voting. The redistributive aspects, rather than the equity aspects, of alternative tax structures are explored.     

Public investment criteria,insurance markets,and income taxes

The evaluation of small government investments is studied in a one-commodity, two-period world with risk and income taxation, assuming both complete and incomplete insurance markets. When marginal personal tax rates differ or markets are incomplete, there are at least two interpretations of the assumption that the distribution of income is optimal. The correct discount rate for riskless investment depends on which interpretation is chosen. The correct adjustment for risk generally does not. The use of nonmarket information - relating the returns from the proposed investment to those from ongoing activities - to compute this adjustment is explored.     

Public sector health insurance trusts

Public sector associations have successfully developed and run employee health insurance pools for almost 30 years, providing members with savings and flexibility not available from commercial health insurance carriers. This article looks at the models, technical tools and governance philosophy that have contributed to their success in a very challenging business environment.     

Voting over income taxation

A major problem of the positive theory of income taxation is to explain why statutory income tax schedules in practice are marginal-rate progressive. While it is commonly believed that this is but a simple consequence of the fact that the number of relatively poor voters exceeds that of richer voters in general, putting this contention in a voting equilibrium context is not a trivial task. We do this here in the context of nonlinear taxation and attempt to provide a formal argument in support of this heuristic claim. We first establish the existence of mixed strategy equilibria and identify certain cases in which marginal-rate progressive taxes are chosen almost surely by the political parties. Unfortunately, we also find that if the tax policy space is not artificially constrained, the support of at least one equilibrium cannot be contained within the set of marginal-rate progressive taxes.     

Unemployment insurance and redistributive taxation

This paper studies the simultaneous determination of the socially optimal levels of unemployment insurance, income taxation and experience rating. It argues that there is a normative justification for state unemployment insurance. When the government wishes to use redistributive taxes, but cannot enforce lump-sum transfers, it is not socially optimal for there to be full experience rating of unemployment insurance schemes: one distortion should be used to off-set another. The state must then intervene in the provision of insurance for those without jobs.     

Externalities and optimal taxation

This paper reexamines the optimal tax design problem (income and commodities) in the presence of externalities. The nature of the second–best, and the choice of the tax instruments, are motivated by the informational structure in the economy. The main results are: (i) environmental levies (linear or nonlinear) differ in formula from Pigouvian taxes by the expressions for the optimal tax on private goods; (ii) externalities do not affect commodity tax formulas (linear and nonlinear) for private goods; (iii) externalities do not affect the income tax structure if commodity taxes are nonlinear and affect it if commodity taxes are linear; and (iv) a general income tax plus strictly Pigouvian taxes are sufficient for efficient taxation if individuals of different types have identical marginal rates of substitution (at any given consumption bundle).     

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.     

Optimum income taxation and layoff taxes

This paper analyzes optimum income taxation in a model with endogenous job destruction that gives rise to unemployment. It is shown that optimal tax schemes comprise both payroll and layoff taxes when the state provides public unemployment insurance and aims at redistributing income. The optimal layoff tax is equal to the social cost of job destruction, which amounts to the sum of unemployment benefits (that the state pays to unemployed workers) and payroll taxes (that the state does not get when workers are unemployed).