A summary of my research portfolio and longer term agenda is here
Cognitive Endurance as Human Capital (available open access from QJE)
with Supreet Kaur, Geeta Kingdon and Heather Schofield, The Quarterly Journal of Economics, Volume 140, Issue 2, May 2025, Pages 943–1002
Abstract: Schooling may build human capital not only by teaching academic skills but by expanding the capacity for cognition. We focus specifically on cognitive endurance: the ability to sustain effortful mental activity over a continuous stretch of time. As motivation, we document that globally and in the United States, the poor exhibit cognitive fatigue more quickly than the rich do across field settings; they also attend schools that offer fewer opportunities to practice thinking for continuous stretches. Using a field experiment with 1,600 Indian primary school students, we randomly increase the amount of time students spend in sustained cognitive activity during the school day—using either math problems (mimicking good schooling) or nonacademic games (providing a pure test of our mechanism). Each approach markedly improves cognitive endurance: students show 22% less decline in performance over time when engaged in intellectual activities—listening comprehension, academic problems, or IQ tests. They also exhibit increased attentiveness in the classroom and score higher on psychological measures of sustained attention. Moreover, each treatment improves students’ school performance by 0.09 standard deviations. This indicates that the experience of effortful thinking itself—even when devoid of any subject content—improves general cognitive capacity. Finally, we complement these results with quasi-experimental variation indicating that an additional year of schooling improves cognitive endurance, but only in higher-quality schools. Our findings suggest that schooling disparities may further disadvantage poor children by hampering the development of a core mental capacity.
Pre-registration: https://www.socialscienceregistry.org/trials/2673
Featured on The Report Card Podcast, the Freakonomics Podcast (Part 1 and Part 2), and PNAS Magazine
Inducing Positive Sorting through Performance Pay: Experimental Evidence from Pakistani Schools
with Tahir Andrabi
Abstract: Attracting and retaining high-quality teachers has a large social benefit, but it is challenging for schools to identify good teachers ex-ante. This paper uses teachers' contract choices and a randomized controlled trial of performance pay with 7,000 teachers in 243 private schools in Pakistan to study whether performance pay affects the composition of teachers. Consistent with adverse selection models, we find that performance pay induces positive sorting: both among teachers with higher latent ability and among those with a more elastic effort response to incentives. Teachers also have better information about these dimensions of type than their principals. Using two additional treatments, we show effects are more pronounced among teachers with better information about their quality and teachers with lower switching costs. Accounting for these sorting effects, the total effect of performance pay on test scores is twice as large as the direct effect on the existing stock of teachers, suggesting that analyses that ignore sorting effects may substantially understate the effects of performance pay.
Featured on VoxDev and Econimate.
Pre-registration: https://www.socialscienceregistry.org/trials/4471
Subjective versus Objective Incentives and Employee Productivity
with Tahir Andrabi
Abstract: A central challenge facing firms is how to incentivize employees. While objective, output-based incentives can motivate effort, they may lead employees to reduce effort on non-incentivized outcomes and may fail in settings where effort is weakly tied to output. We study the effect of subjective incentives (manager evaluation) and objective incentives (test scores) for teachers using an RCT in 234 Pakistani schools. First, we show that subjective and objective incentives increase test scores equally, relative to no incentives. However, objective incentives decrease non-test score student outcomes. Second, we show that teachers' effort response is very different under each scheme, with pedagogy only improving under subjective incentives. Finally, we rationalize these effects through the lens of a moral hazard model with multi-tasking. We use additional variation to isolate the causal effect of contract noise and distortion and show that these channels explain our reduced form effects.
Pre-registration: https://www.socialscienceregistry.org/trials/3835
Understanding Discrimination by Managers
Abstract: Pakistan ranks in the lowest decile in female labor force participation, and even in sectors where women are more prevalent, such as teaching, they earn 70 cents for each dollar men earn. In this project, I test the extent to which statistical versus financial discrimination explains these pay gaps. I partner with 250 schools to randomly vary i). how often managers observe a given employee and ii). whether manager evaluations affect employee’s pay or are just used for feedback and see whether this changes how managers evaluate their employees. First, I find that when their are no stakes associated with performance evaluations, there is no gender bias. This is true both using data from actual performance evaluations, controlling for the aspects of performance I observe, and for randomized vignettes varying the gender of the teacher. In contrast, when principals' evaluations determine teachers' end of year raise, we see that female teachers receive significantly lower ratings. However, when principals are randomly assigned to conduct classroom observations of teachers, this lowers their evaluations of male teachers and results in gender parity in evaluation scores even under financial stakes.
Understanding the Social Network Premium in Hiring Low-Wage Workers
with Maryiam Haroon
In South Asia, three-quarters of ultra-poor households report casual labor (short-term work in agriculture, construction, and manual labor) as their primary form of income. Employers seeking to hire laborers rely almost exclusively on their social network, meaning less connected and marginalized groups are often severely disadvantaged. In this project, we seek to understand why employers rely so heavily on social networks to hire. We partner with a construction firm and randomly vary the information, incentives, and monitoring structure for hiring managers to tease apart the five main hypothesizes that have been proposed to explain the role of social networks in hiring: information asymmetries, reciprocity, match-specific productivity, homophily or simply that more connected works are also more productive. We then test whether employers change their hiring patterns and laborers change their behavior under these different conditions. By understanding why employers rely on social networks, we can better design policies to serve socially disconnected workers.
This project is currently in the field. More on this project here.
School Financing and Principal Decision-Making in Indonesia with Daniel Suryadarma
Increasing Early Childhood Vaccination in Pakistan with Rachel Glennerster, Maryiam Haroon, and Leah Rosenzweig