I am an economist at the Development Impact Evaluation Unit (DIME) at the World Bank in Washington, DC.

My research investigates barriers to agricultural modernization in low-income countries, why they exist and how to overcome them.

My e-mail address is blerva [at] worldbank.org and you can find my CV here.


Journal of Development Economics, forthcoming, with K. Burchardi, J. de Quidt, S. Gulesci, and S. Tripodi

Researchers frequently use variants of the Becker-DeGroot-Marschak (BDM) mechanism to elicit willingness to pay (WTP). These variants involve numerous incentive-irrelevant design choices, some of which carry advantages for implementation but may deteriorate participant comprehension or trust in the mechanism, which are well-known problems with the BDM. We highlight three such features and test them in the field in rural Uganda, a relevant population for many recent applications. Comprehension is very high, and 86 percent of participants bid optimally for an induced-value voucher, with little variation across treatments. This gives confidence for similar applications, and suggests the comprehension-expediency trade-off is mild.

The Quarterly Journal of Economics 134(1):281-347, 2019, with K. Burchardi, S. Gulesci, and M. Sulaiman.

Agricultural productivity is particularly low in developing countries. Output sharing rules that make farmers less-than-full residual claimants are seen as a potentially important driver of low agricultural productivity. We report results from a field experiment designed to estimate and understand the effects of sharecropping contracts on agricultural input choices, risk-taking, and output. The experiment induced variation in the terms of sharecropping contracts. After agreeing to pay 50% of their output to the landlord, tenants were randomized into three groups: (i) some kept 50% of their output; (ii) others kept 75%; (iii) others kept 50% of output and received a lump sum payment at the end of their contract, either fixed or stochastic. We find that tenants with higher output shares utilized more inputs, cultivated riskier crops, and produced 60% more output relative to control. Income or risk exposure have at most a small effect on farm output; the increase in output should be interpreted as an incentive effect of the output sharing rule.

Work in Progress

I investigate how positive externalities contribute to underadoption of agricultural technology among sub-Saharan African farmers. Understanding whether and which types of externalities affect adoption is important both to shed light on human behavior and to formulate optimal policies regarding subsidies and targeting. I focus on the adoption of pest-control technologies. A farmer can benefit in two ways if another adopts: i) she can learn about the technology, a knowledge externality and ii) she can face a lower infection probability, a contagion externality. My approach develops in four steps. First, I establish that pest-control technologies are desired. I measure the value farmers attach to adopting pest-control technologies, and find it is equal to four days' wage. Second, I document that farmers anticipate positive spillovers. The median value a farmer assigns to another farmer adopting pest control technologies is two days' wage. Third, I show that farmers are responsive to changes in positive externalities. I generate random variation in a farmer's beliefs over knowledge and contagion externalities and find changes in beliefs affect the value she assigns to others' adoption. Finally, I estimate that while the private benefit of technology adoption is lower than the cost of the technology, the social benefit is both larger than the cost and at least 18 times larger than the private benefit. My results support the view that local economies may be caught in a low-adoption equilibrium which hinders agricultural productivity growth.

Coverage: World Bank Development Impact Blog, NYU Wagner's Financial Access InitiativeWinner of: UniCredit Best Presentation Award, Petralia 2019

A Tale of Many Constraints: the Impact of a Multi-faceted Education Program

with D. Ferris and M. Fornasari

We study the impacts of the MasterCard Foundation Scholars Program- a merit program for pupils entering secondary school in Uganda. The program provides school fees, placement into a top-100 secondary education institution in the country, school inputs, a teacher mentor and a stipend. High-achieving students from disadvantaged economic backgrounds are targeted. Exploiting the randomized assignment of eligible students to the program, we document the impact of the scholarship on both individual recipients and their households. We find that the program has large positive effects on enrollment and the test scores of recipients. The program is also beneficial to a recipient’s household as consumption, durable assets and savings increase. The psychological wellbeing of mothers also improves dramatically. The impact on siblings is more ambiguous. Siblings enrolled in primary school at baseline are not better off than comparable children in non-recipient households. Siblings enrolled in secondary school at baseline experience an improvement in school quality, as measured by higher school fees and being enrolled in a private school. Therefore, program benefits are not equally distributed among household members, potentially affecting within-household inequality. Overall, the two-year impacts of the program are in line with anti-poverty interventions that provide a similar monetary value to recipients.

Credit Constraints and Capital Allocation in Agriculture: Theory and Evidence from Uganda

with K. Burchardi, J. de Quidt and S. Tripodi