Research Database

We review methods used to numerically compute optimal Mirrleesian tax and transfer schedules in heterogeneous agent economies. We show that the coarseness of the productivity grid, while a technical detail in terms of theory, is critical for delivering quantitative policy prescriptions. Existing methods are reliable only when a very fine grid is used. The problem is acute for computational approaches that use a version of the Diamond-Saez implicit optimal tax formula. If using a very fine grid for productivity is impractical, then optimizing within a flexible parametric class is preferable to the non-parametric Mirrleesian approach.

What structure of income taxation maximizes the social benefits of redistribution while minimizing the social harm associated with distorting the allocation of labor input? Many authors have advocated scrapping the current tax system, which redistributes primarily via marginal tax rates that rise with income, and replacing it with a flat tax system, in which marginal tax rates are constant and redistribution is achieved via non-means-tested transfers. In this paper we compare alternative tax systems in an environment with distinct roles for public and private insurance. We evaluate alternative policies using a social welfare function designed to capture the taste for redistribution reflected in the current tax system. In our preferred specification, moving to the optimal flat tax policy reduces welfare, whereas moving to the optimal fully nonlinear Mirrlees policy generates only tiny welfare gains. These findings suggest that proposals for dramatic tax reform should be viewed with caution.

In this paper we construct a stochastic overlapping-generations general equilibrium model in which households are subject to aggregate shocks that affect both wages and asset prices. We use a calibrated version of the model to quantify how the welfare costs of severe recessions are distributed across different household age groups. The model predicts that younger cohorts fare better than older cohorts when the equilibrium decline in asset prices is large relative to the decline in wages, as observed in the data. Asset price declines hurt the old, who rely on asset sales to finance consumption, but benefit the young, who purchase assets at depressed prices. In our preferred calibration, asset prices decline more than twice as much as wages, consistent with the experience of the US economy in the Great Recession. A model recession is approximately welfare-neutral for households in the 20–29 age group, but translates into a large welfare loss of around 10% of lifetime consumption for households aged 70 and over.

Macroeconomics is evolving from the study of aggregate dynamics to the study of the dynamics of the entire equilibrium distribution of allocations across individual economic actors. This article reviews the quantitative macroeconomic literature that focuses on household heterogeneity, with a special emphasis on the “standard” incomplete markets model. We organize the vast literature according to three themes that are central to understanding how inequality matters for macroeconomics. First, what are the most important sources of individual risk and cross-sectional heterogeneity? Second, what are individuals’ key channels of insurance? Third, how does idiosyncratic risk interact with aggregate risk?

In a standard two-country international macro model, we ask whether imposing restrictions on international non contingent borrowing and lending is ever desirable. The answer is yes. If one country imposes capital controls unilaterally, it can generate favorable changes in the dynamics of equilibrium interest rates and the terms of trade, and thereby benefit at the expense of its trading partner. If both countries simultaneously impose capital controls, the welfare effects are ambiguous. We identify calibrations in which symmetric capital controls improve terms of trade insurance against country-specific shocks and thereby increase welfare for both countries.

This paper evaluates the role of rising income inequality in explaining observed growth in college tuition. We develop a competitive model of the college market, in which college quality depends on instructional expenditure and the average ability of admitted students. An innovative feature of our model is that it allows for a continuous distribution of college quality. We find that observed increases in US income inequality can explain more than half of the observed rise in average net tuition since 1990 and that rising income inequality has also depressed college attendance.

To slow the spread of COVID-19, many countries are shutting down non-essential sectors of the economy. Older individuals have the most to gain from slowing virus diffusion. Younger workers in sectors that are shuttered have the most to lose. In this paper, we build a model in which economic activity and disease progression are jointly determined. Individuals differ by age (young and retired), by sector (basic and luxury), and by health status. Disease transmission occurs in the workplace, in consumption activities, at home, and in hospitals. We study the optimal economic mitigation policy of a utilitarian government that can redistribute across individuals, but where such redistribution is costly. We show that optimal redistribution and mitigation policies interact, and reflect a compromise between the strongly diverging preferred policy paths of different subgroups of the population. We find that the shutdown in place on April 12 is too extensive, but that a partial shutdown should remain in place through the fall. Finally, people prefer deeper and longer shutdowns if a vaccine is imminent, especially the elderly.

This paper studies optimal taxation of earnings when the degree of tax progressivity is allowed to vary with age. The setting is an overlapping-generations model that incorporates irreversible skill investment, flexible labor supply, ex-ante heterogeneity in the disutility of work and the cost of skill acquisition, partially insurable wage risk, and a life cycle productivity profile. An analytically tractable version of the model without intertemporal trade is used to characterize and quantify the salient trade-offs in tax design. The key results are that progressivity should be U-shaped in age and that the average marginal tax rate should be increasing and concave in age. These findings are confirmed in a version of the model with borrowing and saving that we solve numerically.

We conduct a systematic empirical study of cross-sectional inequality in the United States, integrating data from the Current Population Survey, the Panel Study of Income Dynamics, the Consumer Expenditure Survey, and the Survey of Consumer Finances. In order to understand how different dimensions of inequality are related via choices, markets, and institutions, we follow the mapping suggested by the household budget constraint from individual wages to individual earnings, to household earnings, to disposable income, and, ultimately, to consumption and wealth. We document a continuous and sizable increase in wage inequality over the sample period. Changes in the distribution of hours worked sharpen the rise in earnings inequality before 1982, but mitigate its increase thereafter. Taxes and transfers compress the level of income inequality, especially at the bottom of the distribution, but have little effect on the overall trend. Finally, access to financial markets has limited both the level and growth of consumption inequality.

How does a country’s choice of exchange rate regime impact its ability to borrow from abroad? We build a small open economy model in which the government can potentially respond to shocks via domestic monetary policy and by international borrowing. We assume that debt repayment must be incentive compatible when the default punishment is equivalent to permanent exclusion from debt markets. We compare a floating regime to full dollarization.

We find that dollarization is potentially beneficial, even though it means the loss of the monetary instrument, precisely because this loss can strengthen incentives to maintain access to debt markets. Given stronger repayment incentives, more borrowing can be supported, and thus dollarization can increase international financial integration. This prediction of theory is consistent with the experiences of El Salvador and Ecuador, which recently dollarized, as well as with that of highly-indebted countries like Italy which adopted the Euro as part of Economic and Monetary Union: in each case, around the time of regime change, spreads on foreign currency government debt declined substantially.