Sanjit Dhami

Optimal Income Taxation in the Presence of Tax Evasion: Expected Utility Versus Prospect Theory

The predictions of expected utility theory (EUT) applied to tax evasion are flawed on two counts: (i) They are quantitatively in error by huge orders of magnitude. (ii) Higher taxation is predicted to lower evasion, which is at variance with the evidence. An emerging literature in behavioral economics, most notably based on prospect theory (PT), has shown that behavioral economics is much better at explaining tax evasion. We extend this literature to incorporate issues of optimal taxation. As a benchmark for a successful theory, we require that it should explain, jointly, the facts on the tax rate, tax gap and the level of government expenditure. We find that when taxpayers use EUT (respectively, PT) and the optimal tax is derived from a social welfare function that also uses EUT (respectively, PT), then, the calibration results are completely at odds with the facts. However, when taxpayers use PT but the social welfare function uses standard EUT, there is a very close match between the predictions and the facts. This has important implications for context dependent preferences but also for the newly emerging literature on liberalism versus paternalism in behavioral economics.

A note on the Loewenstein–Prelec theory of intertemporal choice

In one of the major contributions to behavioral economics, Loewenstein and Prelec (1992) set the foundations for the behavioral approach to decision making over time. We correct a number of errors in Loewenstein and Prelec (1992). Furthermore, we provide a correct, more direct and simpler derivation of their generalized hyperbolic discounting formula that has formed the basis of much recent work on temporal choice.

Existence of a Condorcet Winner When Voters Have Other-Regarding Preferences

In standard political economy models, voters are ‘self-interested’ i.e. care only about ‘own’ utility. However, the emerging evidence indicates that voters often have ‘other-regarding preferences’ (ORP), i.e., in deciding among alternative policies voters care about their payoffs relative to others. We extend a widely used general equilibrium framework in political economy to allow for voters with ORP, as in Fehr- Schmidt (1999). In line with the evidence, these preferences allow voters to exhibit ‘envy’ and ‘altruism’, in addition to the standard concern for ‘own utility’. We give sufficient conditions for the existence of a Condorcet winner when voters have ORP. This could open the way for an incorporation of ORP in a variety of political economy models. Furthermore, as a corollary, we give more general conditions for the existence of a Condorcet winner when voters have purely selfish preferences.

Evidential Equilibria: Heuristics and Biases in Static Games of Complete Information

Standard equilibrium concepts in game theory find it difficult to explain the empirical evidence from a large number of static games, including the prisoners’ dilemma game, the hawk-dove game, voting games, public goods games and oligopoly games. Under uncertainty about what others will do in one-shot games, evidence suggests that people often use evidential reasoning (ER), i.e., they assign diagnostic significance to their own actions in forming beliefs about the actions of other like-minded players. This is best viewed as a heuristic or bias relative to the standard approach. We provide a formal theoretical framework that incorporates ER into static games by proposing evidential games and the relevant solution concept: evidential equilibrium (EE). We derive the relation between a Nash equilibrium and an EE. We illustrate these concepts in the context of the prisoners’ dilemma game.

An extension of the Becker proposition to non-expected utility theory

In a seminal paper, Becker (1968) showed that the most efficient way to deter crime is to impose the severest possible penalty (to maintain adequate deterrence) with the lowest possible probability (to economize on costs of enforcement). We shall call this the Becker proposition (BP). The BP is derived under the assumptions of expected utility theory (EU). However, EU is heavily rejected by the evidence. A range of non-expected utility theories have been proposed to explain the evidence. The two leading alternatives to EU are rank dependent utility (RDU) and cumulative prospect theory (CP). The main contributions of this paper are: (1) We formalize the BP in a more satisfactory manner. (2) We show that the BP holds under RDU and CP. (3) We give a formal behavioral approach to crime and punishment that could have applicability to a wide range of problems in the economics of crime.

The Hyperbolic Punishment Function

Abstract All models in Law and Economics use punishment functions (hereafter, PF) that incorporate a trade-off between probability of detection, p, and punishment, F. Suppose society wishes to minimize the total costs of enforcement and damages from crime, T( p,F). For a given p, an optimal punishment function (OPF) determines an F that minimizes T( p,F). A popular and tractable PF is the hyperbolic punishment function (HPF). We show that the HPF is an OPF for a large class of total cost functions. Furthermore, the HPF is an upper (lower ) bound for an even larger class of punishment functions. If the HPF cannot (can) deter crime, then none (all ) of the PF’s for which the HPF is an upper (lower ) bound can deter crime. Thus, if one can demonstrate that a particular policy is ineffective (effective) under the HPF, there is no need to even compute the OPF. Our results should underpin an even greater use of the HPF. We give illustrations from mainstream and behavioral economics.

Corruption and the Provision of Public Output in a Hierarchical Asymmetric Information Relationship

This paper develops a principal-agent model to explore the interaction of corruption, bribery, and political oversight of production. Under full information, an honest politician achieves the first best while a dishonest politician creates shortages and bribes. Under asymmetric information, an honest politician may create more shortages relative to a dishonest one, but the latter creates more bribes. The model identifies a tradeoff between bribery and efficiency. This helps to reconcile some conflicting results on the implications of corruption for the size of the public sector. It also provides new results on the circumstances under which an improvement in the auditing technology is beneficial. The paper identifies conditions under which corruption is welfare enhancing. However, the paper also shows that under precisely these conditions private provision, even by an unregulated monopolist, would be better than public provision.

A general theory of time discounting: The reference-time theory of intertemporal choice

We develop a general theory of intertemporal choice: the reference-time theory, RT. RT is a synthesis of ideas from the generalized hyperbolic model (Loewenstein and Prelec 1992), the quasi-hyperbolic model (Phelps and Pollak 1968, Laibson 1997) and subadditivity of time discounting (Roelofsma and Read 2000, Read 2001 and Scholten and Read 2006a). These models are extended to allow for (i) reference points for time and wealth, and (ii) different discount functions for gains and losses. RT is able to account for all the 6 main anomalies of time discounting: gain-loss asymmetry, magnitude effect, common difference effect, delay-speedup asymmetry, apparent intransitivity of time preferences, and non-additivity of time discounting. We provide a class of utility functions compatible with RT. We show how RT can be extended to incorporate uncertainty and attribute models of intertemporal choice.

Optimal Distribution of Powers in a Federation: A Simple, Unified Framework

In a federation with n >= 2 regions the relative optimality of six regimes- autarky, centralization, unregulated devolution, regulated devolution, direct democracy, and revenue maximising leviathan, is examined. Public policy consists of redistribution and regional public good provision. Regional incomes are uncertain and correlated while estimates of the usefulness of regional public goods are uncertain; the federal government’s estimates are noisier relative to those of regional governments. The optimality of each regime is influenced by four margins- regional insurance, coarseness of federal information, internalisation of spillovers and ‘raiding the commons’. Regulated devolution is the only regime that is capable of producing the constrained first best level of public goods. Federal insurance under the two regimes of direct democracy and a federal leviathan, can be inadequate relative to that under a utilitarian federal government. An increase in the number of regions has important implications for insurance and raiding the commons. The median region’s choice of redistribution under direct democracy is influenced in important ways by the distribution of regional uncertainties. The paper synthesises a significant proportion of the existing literature in a single model and also provides several new results.

A Simple Model of Optimal Tax Systems: Taxation, Measurement and Uncertainty

The neglect of administrative issues is a serious limitation of optimal tax theory, with implications for its practical applicability. Under uncertainty, the problems for optimal tax theory are compounded when the full set of tax instruments is neglected. These twin issues are addressed in this paper, by focussing on a fundamental implication of administrative problems, namely, that the tax bases are measured with some error. Consumption taxes can perform the ‘social insurance role of taxation’; a role previously ascribed only to income taxes. A combination of income and consumption taxes can hedge income and measurement-error risks better, relative to the imposition of these taxes alone. The optimal taxes are decreasing in the imprecision with which the corresponding tax base is measured. The taxpayer engages in precautionary savings, in response to uncertainty arising on account of income and measurement problems. Differential commodity taxes, tailored to the measurability characteristics of the different tax bases, dominate uniform commodity taxes. Furthermore, the paper provides a simple, tractable framework for optimal tax theorists interested in diverse kinds of uncertain situations.