Research Database

To to get the COVID-19 virus under control, many countries have shut down parts of the economy. Older individuals have the most to gain from slowing virus diffusion. Younger workers in sectors that are shuttered have most to lose. We build a model in which economic activity and disease progression are jointly determined. Individuals differ by age (young, retired), by sector (basic, luxury), and by health status. Disease transmission occurs in the workplace, through consumption, at home, and in hospitals. We study the optimal economic mitigation policy for a government that can redistribute through taxes and transfers, but where taxation distorts labor supply and output. Optimal redistribution and mitigation policies interact, and more modest shutdowns are optimal when redistribution creates tax distortions. A harder but shorter shutdown is preferred as vaccines become available in the first half of 2021.

Applying the Foster, Haltiwanger, and Krizan (FHK) (2001) decomposition to plant-level manufacturing data from Chile and Korea, we find that the entry and exit of plants account for a larger fraction of aggregate productivity growth during periods of fast GDP growth. Studies of other countries confirm this empirical relationship. To analyze this relationship, we develop a simple model of firm entry and exit based on Hopenhayn (1992) in which there are analytical expressions for the FHK decomposition. When we introduce reforms that reduce entry costs or reduce barriers to technology adoption into a calibrated model, we find that the entry and exit terms in the FHK decomposition become more important as GDP grows rapidly, just as they do in the data from Chile and Korea.

We provide sufficient conditions for the feasibility of a Pareto-improving fiscal policy when the risk-free interest rate on government bonds is below the growth rate (r < g) or there is a markup between price and marginal cost. We do so in the class of incomplete markets models pioneered by Bewley-Huggett-Aiyagari, but we allow for an arbitrary amount of ex ante heterogeneity in terms of preferences and income risk. We consider both the case of dynamic inefficiency as well as the more plausible case of dynamic efficiency. The key condition is that seigniorage revenue raised by government bonds exceeds the increase in the interest rate times the initial capital stock. The Pareto improving fiscal policies weakly expand every agent's budget set at every point in time. The policies improve risk sharing and potentially guide the economy to a more efficient level of capital. We establish that debt and investment associated with Pareto improving policies along the transition may be complements, rather than the traditional substitutes.

Declining search frictions generate productivity growth by allowing workers to find jobs for which they are better suited. The return of declining search frictions on productivity varies across different types of workers. For workers who are "jacks of all trades" in the sense that their productivity is nearly independent from the distance between their skills and the requirements of their job—declining search frictions lead to minimal productivity growth. For workers who are "masters of one trade" in the sense that their productivity is very sensitive to the gap between their individual skills and the requirements of their job—declining search frictions lead to fast productivity growth. As predicted by this view, we find that workers in routine occupations have low wage dispersion and growth, while workers in non-routine occupations have high wage dispersion and growth.

This paper presents a continuous-time model of sovereign debt. In it, a relatively impatient sovereign government’s hidden type switches back and forth between a commitment type, which cannot default, and an optimizing type, which can default on the country’s debt at any time, and assume outside lenders have particular beliefs regarding how a commitment type should borrow for any given level of debt and bond price. We show that if these beliefs satisfy reasonable assumptions, in any Markov equilibrium, the optimizing type mimics the commitment type when borrowing, revealing its type only by defaulting on its debt at random times. Further, in such Markov equilibria (the solution to a simple pair of ordinary differential equations), there are positive gross issuances at all dates, constant net imports as long as there is a positive equilibrium probability that the government is the optimizing type, and net debt repayment only by the commitment type. For countries that have recently defaulted, the interest rate the country pays on its debt is a decreasing function of the amount of time since its last default, and its total debt is an increasing function of the amount of time since its last default. For countries that have not recently defaulted, interest rates are constant.

This paper studies lockdown policy in a dynamic economy without government commitment. Lockdown imposes a cap on labor supply, which improves health prospects at the cost of economic output and consumption. A government would like to commit to the extent of future lockdowns in order to guarantee an economic outlook that supports efficient levels of investment into intermediate inputs. However, such a commitment is not credible, since investments are sunk at the time when the government chooses a lockdown. As a result, lockdown under lack of commitment deviates from the optimal policy. Rules that limit a government’s lockdown discretion can improve social welfare, even in the presence of noncontractible information. Quantitatively, lack of commitment causes lockdown to be significantly more severe than is socially optimal. The output and consumption loss due to lack of commitment is greater for higher intermediate input shares, higher discount rates, higher values of life, higher disease transmission rates at and outside of work, and longer vaccine arrival times.

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.