Working papers
The short-run impact of US tariffs on an interconnected world
With José-María Da-Rocha (Universidade de Vigo). Working paper, September 2026.
We assess the short-run effects of U.S. tariffs using a multi-country, multi-sector model with a fixed global Leontief matrix, calibrated to the OECD Inter-Country Input-Output tables. A 25% tariff on Canada, China and Mexico, 15% on the EU and 10% on all other countries reduces U.S. GDP in international dollars by 1.48%, while Canada’s, China’s and Mexico’s fall by 1.21%, 1.14% and 0.85%, respectively. Rather than reducing the trade deficit, tariffs widen it through a J-curve effect and shift real trade flows to competitors.
- Even a uniform 10% U.S. tariff lowers world GDP by 0.73%, and the U.S. loses the most (0.83%).
- Escalating to a 145% tariff on China quadruples the damage: world GDP falls 3.38% and the U.S. 3.78%, the largest loss in the sample.
- Trade is rerouted, not destroyed: U.S. trade openness falls 2.40% while Mexico’s rises 2.84%.
Fiduciary Coinage and Its Collapse in Ancient Rome
With José-María Da-Rocha (Universidade de Vigo). Working paper, September 2026.
Roman Egypt’s closed tetradrachm circulated for decades above its metal value. Four series make this observable: Greenland ice-core lead for silver production, papyrus grain prices, coin fineness, and silver in circulation, from 253,417 hoard coins. Inflation reached Egypt as two coordination shocks. A two-equilibrium model predicts the 296 CE jump as the release of the coin’s premium, and the jump matches. Over seven centuries the silver price of wheat mean-reverts while nominal prices rise five to six orders of magnitude. Debasement reached circulating coin a generation after the mint, and Gresham’s law fails inside the same hoards.
- Egypt’s 296 CE price jump of 2.1× matches the premium its token coinage had accumulated; the model predicts 1.7–2.3×.
- Half of the Severan cut in fineness reached the coin in circulation only 36 years later, measured from 253,417 dated hoard coins.
- The silver price of wheat mean-reverts for seven centuries while nominal prices explode: the great Roman inflation was overwhelmingly monetary.
Publications
The Effect of Non-Contributory Pensions on Saving in Mexico
With Catalina Amuedo-Dorantes and Laura Juárez. Economic Inquiry 57(2): 931–952, 2019.
Abstract
This paper examines the effects of noncontributory pension programs at the federal and state levels on Mexican households’ saving patterns using micro data from the Mexican Income and Expenditure Survey. We find that the federal program curtails saving among households whose oldest member is either 18–54 or 65–69 years old, possibly through anticipation effects, a decrease in the longevity risk faced by households, and a redistribution of income between households of different generations. Specifically, these households appear to be reallocating income away from saving into human capital investments, like education and health. Generally, state programs have neither significant effects on household saving, nor does the combination of federal and state programs. Finally, with a few exceptions, noncontributory pensions have no significant impact on the saving of households with members 70 years of age or older—individuals eligible for those pensions, plausibly because of their dissaving stage in the life cycle.
Cross-Subsidies, and the Elasticity of Informality to Social Expenditures: The Case of Mexico’s Seguro Popular
With Julio Leal-Ordoñez. Review of Income and Wealth 64(2): 482–512, 2018.
Abstract
How is the size of the informal sector affected when the distribution of social expenditures across formal and informal workers changes? How is it affected when the tax rate changes along with the generosity of these transfers? In our search model, taxes are levied on formal-sector workers as a proportion of their wage. Transfers, in contrast, are lump-sum and are received by both formal and informal workers. This implies that high-wage formal workers subsidize low-wage formal workers as well as informal workers. We calibrate the model to Mexico and perform counterfactuals. We find that the size of the informal sector is quite inelastic to changes in taxes and transfers. This is due to the presence of search frictions and to the cross-subsidy in our model: for low-wage formal jobs, a tax increase is roughly offset by an increase in benefits, leaving the unemployed approximately indifferent. Our results are consistent with the empirical evidence on the recent introduction of the “Seguro Popular” healthcare program.
The productivity cost of sovereign default: evidence from the European debt crisis
With Esteban Colla and José-María Da-Rocha. Economic Theory 64(4): 611–633, 2017.
Abstract
We calibrate the cost of sovereign defaults using a continuous time model, where government default decisions may trigger a change in the regime of a stochastic TFP process. We calibrate the model to a sample of European countries from 2009 to 2012. By comparing the estimated drift in default relative to that in no-default, we find that TFP falls in the range of 3.70–5.88%. The model is consistent with observed falls in GDP growth rates and subsequent recoveries and illustrates why fiscal multipliers are small during sovereign debt crises.
Social security and retirement across the OECD
Journal of Economic Dynamics and Control 47: 300–316, 2014.
Abstract
Employment to population ratios differ markedly across Organization for Economic Cooperation and Development (OECD) countries, especially for people aged over 55 years. In addition, social security features differ markedly across the OECD, particularly with respect to features such as generosity, entitlement ages, and implicit taxes on social security benefits. This study postulates that differences in social security features explain many differences in employment to population ratios at older ages. This conjecture is assessed quantitatively with a life cycle general equilibrium model of retirement. At ages 60–64 years, the correlation between the simulations of this study’s model and observed data is 0.67. Generosity and implicit taxes are key features to explain the cross-country variation, whereas entitlement age is not.
Taxes, transfers and employment in an incomplete markets model
With Richard Rogerson. Journal of Monetary Economics 57(8): 949–958, 2010.
Abstract
The consequences of increases in the scale of tax and transfer programs are assessed in the context of a model with idiosyncratic productivity shocks and incomplete markets. The effects are contrasted with those obtained in a stand-in household model featuring no idiosyncratic shocks and complete markets. The main finding is that the impact on hours remains very large, but the welfare consequences are very different. The analysis also suggests that tax and transfer policies have large effects on average labor productivity via selection effects on employment.


