Research Database

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.

The direct benefits of infrastructure in developing countries can be large, but if new infrastructure induces in-migration, congestion of other local publicly provided goods may offset the direct benefits. Using the example of rural household electrification in South Africa, we demonstrate the importance of accounting for migration when evaluating welfare gains of spatial programs. We also provide a practical approach to computing welfare gains that does not rely on land prices. We develop a location choice model that incorporates missing land markets and allows for congestion in local land. Using this model, we construct welfare bounds as a function of the income and population effects of the new electricity infrastructure. A novel prediction from the model is that migration elasticities and congestion effects are especially large when land markets are missing. We empirically estimate these welfare bounds for rural electrification in South Africa and show that congestion externalities from program-induced migration reduced local welfare gains by about 40%.

Modern business cycle theory focuses on the study of dynamic stochastic general equilibrium models that generate aggregate fluctuations similar to those experienced by actual economies. We discuss how this theory has evolved from its roots in the early real business cycle models of the late 1970s through the turmoil of the Great Recession four decades later. We document the strikingly different pattern of comovements of macro aggregates during the Great Recession compared to other postwar recessions, especially the 1982 recession. We then show how two versions of the latest generation of real business cycle models can account, respectively, for the aggregate and the cross-regional fluctuations observed in the Great Recession in the United States.

This paper uses an estimated structural model to argue that the option to move in and out of the parental home is an important insurance channel against labor market risk for youths who do not attend college. Using data from the NLSY97, I construct a new monthly panel of parent-youth coresidence outcomes and use it to document an empirical relationship between these movements and individual labor market events. The data is then used to estimate the parameters of a dynamic game between youths and their altruistic parents, featuring coresidence, labor supply and savings decisions. Parents can provide both monetary support through explicit financial transfers, and non-monetary support in the form of shared residence. To account for the data, two types of exogenous shocks are needed. Preference shocks are found to explain most of the cross-section of living arrangements, while labor market shocks account for individual movements in and out of the parental home. I use the model to show that coresidence is a valuable form of insurance, particularly for youths from poorer families. The option to live at home also helps to explain features of aggregate data for low-skilled young workers: their low savings rates and their relatively small consumption responses to labor market shocks. An important implication is that movements in and out of home can reduce the consumption smoothing benefits of social insurance programs.

We use balance sheet data and stock market data for the major U.S. banking institutions during and after the 2007-8 financial crisis to estimate the magnitude of the losses experienced by these institutions because of the crisis. We then use these estimates to assess the impact of the crisis under alternative, and higher, capital requirements. We find that substantially higher capital requirements (in the 20% to 30% range) would have substantially reduced the vulnerability of these financial institutions, and consequently they would have significantly reduced the need of a public bailout.

This paper proposes a new way of modeling age, period, and cohort effects that improves substantively and methodologically on the conventional linear model. The linear model suffers from a well-known identification problem: If we assume an outcome of interest depends on the sum of an age effect, a period effect, and a cohort effect, then it is impossible to distinguish these three separate effects because, for any individual, birth year = current year – age. Less well appreciated is that the model also suffers from a conceptual problem: It assumes that the influence of age is the same in all time periods, the influence of present conditions is the same for people of all ages, and cohorts do not change over time. We argue that in many applications, these assumptions fail. We propose a more general model in which age profiles can change over time and period effects can have different influences on people of different ages. Our model defines cohort effects as an accumulation of age-by-period interactions. Although a long-standing literature on theories of social change conceptualizes cohort effects in exactly this way, we are the first to show how to statistically model this more complex form of cohort effects. We show that the additive model is a special case of our model and that, except in special cases, the parameters of the more general model are identified. We apply our model to analyze changes in age-specific mortality rates in Sweden over the past 150 years. Our model fits the data dramatically better than the additive model. The estimates show that the rate of increase of mortality with age among adults became more steep from 1881 to 1941, but since then the rate of increase has been roughly constant. The estimates also allow us to test whether early-life conditions have lasting impacts on mortality, as under the cohort morbidity phenotype hypothesis. The results give limited support to this hypothesis: The impact of early-life conditions lasts for several years but is unlikely to reach all the way to old age.

Applied general equilibrium (AGE) models, which feature multiple countries, multiple industries, and input-output linkages across industries, have been the dominant tool for evaluating the impact of trade reforms since the 1980s. We review how these models are used to perform policy analysis and document their shortcomings in predicting the industry-level effects of past trade reforms. We argue that, to improve their performance, AGE models need to incorporate product-level data on bilateral trade relations by industry and better model how trade reforms lower bilateral trade costs. We use the least traded products methodology of Kehoe et al. (2015) to provide guidance on how improvements can be made. We provide further suggestions on how AGE models can incorporate recent advances in quantitative trade theory to improve their predictive ability and better quantify the gains from trade liberalization.

This paper develops an overlapping generations model to study the macroeconomic effects of an unexpected elimination of Medicare. We find that a large share of the elderly respond by substituting Medicaid for Medicare. Consequently, the government saves only 46 cents for every dollar cut in Medicare spending. We argue that a comparison of steady states is insufficient to evaluate the welfare effects of the reform. In particular, we find lower ex-ante welfare gains from eliminating Medicare when we account for the costs of transition. Lastly, we find that a majority of the current population benefits from the reform but that aggregate welfare, measured as the dollar value of the sum of wealth equivalent variations, is higher with Medicare.

After the economic reforms that followed the National Revolution of the 1950s, Bolivia seemed positioned for sustained growth. Indeed, it achieved unprecedented growth from 1960 to 1977. Mistakes in economic policies, especially the rapid accumulation of debt due to persistent deficits and a fixed exchange rate policy during the 1970s, led to a debt crisis that began in 1977. From 1977 to 1986, Bolivia lost almost all the gains in GDP per capita that it had achieved since 1960. In 1986, Bolivia started to grow again, interrupted only by the financial crisis of 1998–2002, which was the result of a drop in the availability of external financing. Bolivia has grown since 2002, but government policies since 2006 are reminiscent of the policies of the 1970s that led to the debt crisis, in particular, the accumulation of external debt and the drop in international reserves due to a de facto fixed exchange rate since 2012.

We analyze commitment to employment in an environment in which an infinitely lived firm faces a sequence of finitely lived workers who differ in their ability to produce output. A worker’s ability is initially unknown to both the worker and the firm. A worker’s effort affects the information on ability conveyed by his performance. We characterize equilibria and show that they display commitment to employment only when effort has a persistent but delayed impact on output. In this case, by providing insurance against early termination, commitment to employment encourages workers to exert effort, thus improving the firm’s ability to identify workers’ talent. The incentive value of commitment to retention helps explain the use of probationary appointments in environments in which there is uncertainty about individual ability.