Research Database

What shapes the optimal degree of progressivity of the tax and transfer system? On the one hand, a progressive tax system can counteract inequality in initial conditions and substitute for imperfect private insurance against idiosyncratic earnings risk. On the other hand, progressivity reduces incentives to work and to invest in skills, distortions that are especially costly when the government must finance public goods. We develop a tractable equilibrium model that features all of these trade-offs. The analytical expressions we derive for social welfare deliver a transparent understanding of how preference, technology, and market structure parameters influence the optimal degree of progressivity. A calibration for the U.S. economy indicates that endogenous skill investment, flexible labor supply, and the desire to finance government purchases play quantitatively similar roles in limiting optimal progressivity. In a version of the model where poverty constrains skill investment, optimal progressivity is close to the U.S. value. An empirical analysis on cross-country data offers support to the theory.

We show that a trade model with an exogenous set of heterogeneous firms with fixed operating costs has the same aggregate outcomes as a span-of-control model. Fixed costs in the heterogeneous-firm model are entrepreneurs' forgone wage in the span-of-control model.

During the Great Recession, regions of the United States that experienced the largest declines in household debt also experienced the largest drops in consumption, employment, and wages. Employment declines were larger in the nontradable sector and for firms that were facing the worst credit conditions. Motivated by these findings, we develop a search and matching model with credit frictions that affect both consumers and firms. In the model, tighter debt constraints raise the cost of investing in new job vacancies and thus reduce worker job finding rates and employment. Two key features of our model, on-the-job human capital accumulation and consumer-side credit frictions, are critical to generating sizable drops in employment. On-the-job human capital accumulation makes the flows of benefits from posting vacancies long-lived and so greatly amplifies the sensitivity of such investments to credit frictions. Consumer-side credit frictions further magnify these effects by leading wages to fall only modestly. We show that the model reproduces well the salient cross-regional features of the U.S. data during the Great Recession.

A problem that faces many countries including the United States is how to finance retirement consumption as the population ages. Proposals for switching to a saving-for-retirement system that do not rely on high payroll taxes have been challenged on the grounds that welfare would fall for some groups such as retirees or the working poor. We show how to devise a transition path from the current U.S. system to a saving-for-retirement system that increases the welfare of all current and future generations, with estimates of future gains higher than those found in typically used macroeconomic models. The gains are large because there is more productive capital than commonly assumed. Our quantitative results depend importantly on accounting for differences between actual government tax revenues and what revenues would be if all income were taxed at the income-weighted average marginal tax rates used in our analysis.

This essay reviews the development of neoclassical growth theory, a unified theory of aggregate economic phenomena that was first used to study business cycles and aggregate labor supply. Subsequently, the theory has been used to understand asset pricing, growth miracles and disasters, monetary economics, capital accounts, aggregate public finance, economic development, and foreign direct investment.

The focus of this essay is on real business cycle (RBC) methodology. Those who employ the discipline behind the methodology to address various quantitative questions come up with essentially the same answer—evidence that the theory has a life of its own, directing researchers to essentially the same conclusions when they apply its discipline. Deviations from the theory sometimes arise and remain open for a considerable period before they are resolved by better measurement and extensions of the theory. Elements of the discipline include selecting a model economy or sometimes a set of model economies. The model used to address a specific question or issue must have a consistent set of national accounts with all the accounting identities holding. In addition, the model assumptions must be consistent across applications and be consistent with micro as well as aggregate observations. Reality is complex, and any model economy used is necessarily an abstraction and therefore false. This does not mean, however, that model economies are not useful in drawing scientific inference.

The vast number of contributions made by many researchers who have used this methodology precludes reviewing them all in this essay. Instead, the contributions reviewed here are ones that illustrate methodological points or extend the applicability of neoclassical growth theory. Of particular interest will be important developments subsequent to the Cooley (1995) volume, Frontiers of Business Cycle Research. The interaction between theory and measurement is emphasized because this is the way in which hard quantitative sciences progress.

Many countries are facing challenging fiscal financing issues as their populations age and the number of workers per retiree falls. Policymakers need transparent and robust analyses of alternative policies to deal with demographic changes. In this paper, we propose a simple framework that can easily be matched to aggregate data from the national accounts. We demonstrate the usefulness of our framework by comparing quantitative results for our aggregate model with those of a related model that includes within-age-cohort heterogeneity through productivity differences. When we assess proposals to switch from the current tax and transfer system in the United States to a mandatory saving-for-retirement system with no payroll taxation, we find that the aggregate predictions for the two models are close.

Liabilities ceded by life insurers to shadow reinsurers (i.e., less regulated and unrated off-balance-sheet entities) grew from $11 billion in 2002 to $364 billion in 2012. Life insurers using shadow insurance, which capture half of the market share, ceded 25 cents of every dollar insured to shadow reinsurers in 2012, up from 2 cents in 2002. Our adjustment for shadow insurance reduces risk-based capital by 53 percentage points (or 3 rating notches) and increases default probabilities by a factor of 3.5. We develop a structural model of the life insurance industry and estimate the impact of current policy proposals to limit or eliminate shadow insurance. In the counterfactual without shadow insurance, the average company using shadow insurance would raise prices by 10 to 21 percent, and annual life insurance underwritten would fall by 7 to 16 percent for the industry.

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.