Research
Working papers
Perpetual Motion: High-Frequency Human Mobility in Three African Countries (September 2023)
with Paul Blanchard (Trinity College Dublin) and Doug Gollin (Oxford University), TEP Working Paper No. 0823
Reject & Resubmit, Econometrica
CEPR Discussion Paper DP16661 Bibtex
This paper explores the within-country movements of people in three African countries. Although previous studies in other low-income settings have examined patterns of seasonal migration and daily commuting, much less is known about mobility at other temporal frequencies. This paper draws on a novel source of data from smartphone locations. These data allow us to observe the movements of a large set of individuals over a one-year period. We can characterize with considerable detail the locations that people visit and the frequency with which they make trips. The average smartphone user in our data ventures more than 10 km from home on 12-15% of the days when they are observed. On average, when we observe them away from home, our users are typically 35-50 km from home. We can characterize many of the specific locations that people visit when they are away from home. These include locations associated with shops and markets, government offices, and places offering a range of goods, services, and recreational venues. Big cities seem to be particularly important destinations, perhaps reflecting the range of amenities that they offer to visitors. We develop a conceptual framework that characterizes the role of visits for individuals and provides a number of testable predictions that are consistent with the movement patterns that we observe in the data. Although our sample of smartphone users is not representative of national populations, their mobility patterns offer useful insights into spatial frictions and the geographic patterns of economic activity.
Concrete Thinking About Development (May 2023)
with Keelan Beirne (MIT), CEPR Discussion Paper DP18170
Previous Version (October 2020) Bibtex
Presentation at the IGC/Stanford 2020 Conference on Firms, Trade and Development
Misallocation is increasingly recognized as an important factor in explaining productivity differences across countries. This paper uses new micro-data on key input prices in the construction sector and market structure at a global level to study distortions in construction sector inputs and their consequences. We document that (i) there is large dispersion in construction sector input prices and that cement prices are particularly high in the poorest countries; (ii) cement prices are highest in countries with few firms; (iii) cement plays a significant role in construction sector expenditures, particularly in the poorest countries. To understand the reasons for price differences in cement we estimate a model of oligopoly using both a demand-based instrument and exploiting geological variation in the dispersion of limestone deposits within countries. Our results suggest that lower levels of competition lead to significantly higher prices. Firm-level financial accounts data point toward substantial economic rents. We then embed the oligopoly structure into a dynamic general equilibrium network model to analyse the consequences of distortions on the wider economy. We find that due to cement's network position, distortions have large effects on steady-state output: for every dollar increase in cement profits, steady-state output falls by two. Finally, we find that common ownership in cement is an important source of distortions accounting for between 75% and 85% of the wedge due to markups in cement.
Conscientiousness in the workplace: Evidence from a field experiment in West Africa (March 2024)
with Mathias Allemand (University of Zurich), Sveta Milusheva (The World Bank), Carol Newman (Trinity College Dublin), Brent Roberts (University of Illinois at Urbana-Champaign) and Vincent Thorne (Trinity College Dublin), TEP Working Paper No. 0123
Despite extensive evidence on the importance of non-cognitive skills for labor market outcomes, to what extent training can affect specific skills in adulthood remains an open question. We conducted a randomized controlled trial with low-skilled employed workers in Senegal where workers were randomly assigned to receive a training intervention designed to affect conscientiousness-related skills. We found that treated workers were significantly more likely to stay in their job and had higher earnings nine months after the intervention. Our findings suggest that non-cognitive skills can be affected later in the life cycle and targeted training can have substantial labor market returns.
Publications
Measuring Migration (2021)
Regional Science and Urban Economics, Special Issue on Rural-Urban Migration in Honor of Harris and Todaro, 91.
Do Urban Wage Premia Reflect Lower Amenities? Evidence from Africa (2021)
with Doug Gollin (University of Oxford) and David Lagakos (Boston University)
Journal of Urban Economics, 121.
NBER Working Paper 23916 Bibtex
Intra-household Allocation of Time and Money Across Siblings (2020)
Journal of Economic Behavior & Organization, 179:361-377.
Natural Disasters and Labor Markets (2017)
Journal of Development Economics, 125:40-58.
The Cost of Road Infrastructure in Low- and Middle-Income Countries (2016)
with Paul Collier (University of Oxford) and Måns Söderbom (University of Gothenburg)
The World Bank Economic Review, 30(3): 522-548.
Book chapters
The Role of the Construction Sector in Developing Countries: Some Key Issues (2020)
in Page, J & Tarp, F. (Eds.). Mining for Change: Natural Resources and Industry in Africa, Oxford University Press, see here for a pdf of the book.
Selected work in progress
Constructing Africa’s Cities: Labor Market Effects of Infrastructure Construction
with Kevin Donovan (Yale), Carol Newman (Trinity College Dublin) and Sveta Milusheva (The World Bank)
Urban-Rural Definitions and Spatial Income Gaps
with Doug Gollin (Tufts University), David Lagakos (Boston University) and Shraddha Mandi (Boston University)
Research-related work
Kagera Health and Development Survey 2010: Basic Information Document (2012)
with Joachim De Weerdt (Economic Development Initiatives), Kathleen Beegle (World Bank), Helene Bie Lilleør (Rockwool Foundation), Stefan Dercon (University of Oxford), Kalle Hirvonen (Sussex University) and Sofya Krutikova (University of Oxford), Rockwool Foundation Working Paper Series, Study Paper No. 46.
Agricultural Productivity Growth in Kagera between 1991 and 2004 (2011)
with Fulgence Mishili (Sokoine University of Agriculture), 2011, IGC Working Paper 11/0897, International Growth Centre.
See here for the policy brief.
Literature Review on Microinsurance (2008)
with Stefan Dercon (University of Oxford), Jan-Willelm Gunning (VU University Amsterdam), and Jean-Philippe Platteau (University of Namur), 2008, Microinsurance paper No.1, International Labour Organization, Geneva.