Research

Working Papers

• "End of Apartheid, Not of Inequality: Economic Legacy and Ongoing Discrimination" with Martí Mestieri and Johanna Schauer (STEG Small Research Grant) New version: September 2026

Previously circulated as "End of Apartheid, Not of Inequality: The Slow Transition in a Segregated Economy," CEPR Discussion Paper No. DP20472

[Township list and location] 

Three decades after Apartheid, South Africa remains among the most unequal countries in the world, with inequality increasingly concentrated within the Black population. How much of this inequality reflects the economic legacy of Apartheid, and how much discrimination that outlived it? We combine newly assembled data—geolocated Townships, censuses harmonized over a century, and geocoded commuting records—with a dynastic general equilibrium model of education, entrepreneurship, savings, and location choice under incomplete markets. Starting from Apartheid initial conditions, a race-blind economy reproduces the rise of within-Black inequality but closes the racial gap far too quickly. A single wedge on Black income reconciles the model with the joint dynamics of inequality within and between races. Race-neutral forces account for about a third of the inequality observed in 2011, discrimination for the rest. Discrimination also widens inequality within racial groups, both Blacks and Whites, leaving Whites poorer and less educated than they would otherwise have been. Shutting down the race-neutral frictions one at a time, we find that equalizing education access and quality narrows the racial gap the most and alone lowers total inequality. The other frictions shift inequality from between groups to within them.

• "Insured by Custom, Constrained by Credit: Why Land Titling Stalls"  New version: October 2026

Previously circulated as "Land Property Rights, Financial Frictions, and Resource Allocation in Developing Countries," STEG WP046

Why does customary tenure persist in Sub-Saharan Africa even where titling is open to all and its estimated gains are large? Customary tenure is not only a set of restrictions. By reallocating idle land, it insures households with little land and taxes those with a lot. The households it taxes gain most from a title. Each title lowers the customary transfer to those who stay, so titling decisions are strategic complements. But titling costs must come out of savings, due to limited financial markets. This financial constraint stalls titling before the complementarity can accelerate the reform. In a heterogeneous agent model estimated on Tanzanian panel data, a quarter of customary land is titled over a century and output rises 11 percent, against 24 percent under free titling. Lending households the cost of titling against their plot raises output more within eight years than a century of reform without such loans.

Coverage: World Bank Development Impact Blog

• "Ideas Across Borders: International Knowledge Spillovers and Productivity Growth"  with Enrico Berkes and Martí Mestieri  New version: October 2026

Previously circulated as "Global Innovation Spillovers and Productivity: Evidence from 100 years of World Patent Data," CEPR Discussion Paper No. DP17285

[Online Appendix]   [Fields of Knowledge Correspondence]

How much do international knowledge spillovers contribute to innovation and productivity growth around the world? Using a century of global patent data, we document technological waves led by a changing set of countries and, after 1990, a sharp turn toward foreign knowledge. By the 2000s, patents filed outside the United States and Japan cited foreign patents more than twice as often as domestic ones. To estimate how this reliance affects domestic innovation and productivity, we measure each country-sector's exposure to foreign innovation through the pre-1990 global citation network, including indirect links through third countries and sectors. Over 2000–2014, greater exposure raises subsequent value added per worker and TFP growth, and predicts domestic patenting with an elasticity of about one third. Decomposing TFP growth by knowledge source, both in reduced form and in a Schumpeterian growth model, we find that foreign knowledge accounts for 20 to 30 percent of measured TFP growth outside the United States and Japan, and about 40 percent in three frontier sectors (computer programming, electronics, and pharmaceuticals). The United States and Japan alone account for about a tenth of measured growth, and a fifth in the frontier sectors. Restrictions on the international flow of knowledge would carry first-order productivity costs, concentrated in the countries and sectors that rely most on foreign sources.

Coverage: VoxEU

Published Papers

• "Gendered Impacts of Covid-19 in Developing Countries" with Titan Alon, Matthias Doepke and Michèle Tertilt

AEA Papers and Proceedings, Vol. 112, 272-276, May 2022.

Also available as IZA DP No. 15013, January 2022.

In many high-income economies, the recession caused by the Covid-19 pandemic has resulted in unprecedented declines in women's employment. We examine how the forces that underlie this observation play out in developing countries, with a specific focus on Nigeria, the most populous country in Africa. A force affecting high- and low-income countries alike are increased childcare needs during school closures; in Nigeria, mothers of school-age children experience the largest declines in employment during the pandemic, just as in high-income countries. A key difference is the role of the sectoral distribution of employment: whereas in high-income economies reduced employment in contact-intensive services had a large impact on women, this sector plays a minor role in low-income countries. Another difference is that women's employment rebounded much more quickly in low-income countries. We conjecture that large income losses without offsetting government transfers drive up labor supply in low-income countries during the recovery.

Presentation Slides: [PDF], Codes and Data: [Link to Open ICPSR]

Coverage: WBBM Newsradio

Selected Work in Progress

• "Constructing Structural Change" with Julieta Caunedo and Mayara Felix

[Slides]

Description: Agriculture in rich countries is more productive than in poor countries, uses more machines and has larger farms. We study the forces behind this rise in agricultural productivity, farm mechanization and land consolidation. To do so, we build a general-equilibrium model of agriculture in which heterogeneous farms enter and exit, choose which tasks to perform with machines, and pay a one-time cost to make a task mechanizable. A higher price of labor relative to capital raises mechanization and moves land toward larger, more mechanized farms. Because the cost is sunk, a temporary rise in wages leaves the farms that adapted during it more mechanized after it ends. We examine these predictions in Brazil between 1997 and 2017. Using the entry of large firms, we show that construction, unlike manufacturing, raises the wages and leads to a decline in agricultural employment. Our main evidence comes from Minha Casa Minha Vida, a federal housing program that created a large construction boom. Where the program was larger for political reasons, agricultural wages rose more and agricultural employment fell more. Farms used more tractors, grew larger and produced more per worker. The response differs with local conditions, such as terrain and how mechanized agriculture already was. A quantitative version of the model traces the effects of a five-year construction boom and shows how they depend on the initial capital intensity of agriculture.  

• "What is the Aggregate Impact of Pandemic Education Disruptions in Low-Income Countries" with Titan Alon, Matthias Doepke and Michèle Tertilt

Description: The Covid-19 pandemic has led to prolonged school closures in most countries around the world. This paper aims to quantify the potential impact of pandemic learning losses in developing countries, with a specific focus on sub-Saharan Africa. We argue that both micro and macro channels imply that the repercussions of pandemic education disruptions are more severe in poorer countries than richer economies. First, the evidence suggests that children in low-income countries suffer more significant learning losses. This obtains partly because of the lower availability and efficiency of alternative learning channels such as virtual instruction and partly because of a higher impact on dropout rates, which are amplified by income losses during the pandemic. Second, a given learning loss has a more significant medium-run impact on the economy because recent school graduates make up a larger fraction of the total labor force in low-income economies and because older cohorts have relatively little formal education. We quantify these channels using a macro-development model that matches household-level and aggregate data from Nigeria.

• "The Impacts of Mobile Money on Village Economies: A General Equilibrium Approach"

Description: This paper aims to assess the aggregate effects and the distributional consequences of the adoption of mobile money technology for the rural economy. I propose a two-sector heterogeneous agent model that incorporates occupational choice, endogenous wages, and forward-looking saving decisions. The more developed (urban) sector is motivated to make transfers to a less developed (rural) sector. Moreover, due to limited access to financial services in rural areas, saving technology is subject to potential losses. The introduction of mobile money technology reduces transfer friction between the urban and rural parts of the household and improves rural saving technology. I use existing micro evidence on the effects of mobile money to discipline the model.

Discussions

• Manalis, G. & Mazur, K. “The Mystery of Land Rights: Explorations on Informal Institutions in Ghana” May, 2026 (103rd Carnegie-Rochester-NYU Conference) Slides

• Brooks, W. &  Donovan, K. “Optimal Fertilizer Policy After a Global Shock” July, 2025 (NBER SI Economic Growth 2025) Slides

• Dai, P., Müller, K. &  Verner, E. “Credit Allocation, Collateral, and Economic Development” January, 2025 (ASSA 2025, AFA) Slides

• Mitra, D., Pham, H. &  Ural-Marchand, B. “Exports and Intergenerational Mobility” September, 2024 (Trade and Uneven Development Conference, WB & JIE) Slides