Working Papers


“Scared Straight or Scared to Death? The Effect of Risk Beliefs on Risky Behaviors” [PDF] [Online Appendix]

This paper tests a model of risk compensation that allows for “fatalism”: higher risks lead to more risk-taking, rather than less. Fatalism can be rational if the risk of each act exceeds a threshold value. I test this prediction by randomizing the provision of information about HIV risks in Malawi, and break down the risk elasticity of sexual risk-taking by people’s initial risk beliefs. Matching the model’s predictions, this elasticity varies from -2.3 for the lowest to 2.9 for the highest beliefs. Fatalism is more pronounced among people who think they may be HIV-positive, consistent with the model’s mechanism.

“Income Timing and Liquidity Constraints: Evidence from a Randomized Field Experiment” (with Lasse Brune) [PDF] [Online Appendix]

People in developing countries sometimes desire deferred income streams, which replace more frequent income flows with a single, later lump sum. We study the effects of short-term wage deferral using a randomized experiment with participants in a temporary cash-for-work program. Workers who are assigned to lump-sum payments are five percentage points more likely to purchase a high-return artificial investment. We discuss the role of both barriers to saving and credit constraints in explaining our results. While stated preferences for deferred payments suggest a role for savings constraints, the weight of the evidence is most consistent with a simple model of credit constraints.

“Making the Grade: The Sensitivity of Education Program Effectiveness to Input Choices and Outcome Measures” (with Rebecca Thornton) [PDF][Online Appendix]

This paper demonstrates the acute sensitivity of education program effectiveness to input choices and outcome measures, using a randomized evaluation of a literacy program. The program raises reading scores by 0.64SD and writing scores by 0.45SD. A reduced-cost version instead yields statistically-insignificant reading gains and large negative effects (-0.30SD) on writing. Detailed classroom observations provide evidence on the mechanisms driving the results, indicating the importance of increased productivity of time, rather than increased time on task. Changes in the use of materials as well as machine learning and mediation analysis results also suggest important complementarities in the education production function.

“Peers and Motivation at Work: Evidence from a Firm Experiment in Malawi” (with Lasse Brune and Eric Chyn)

This paper sheds light on the nature of workplace peer effects by analyzing an experiment with a tea estate in Malawi. We randomly allocate tea-harvesting workers to locations on fields to estimate the impact of peers on worker performance. Using data on daily productivity, we find strong evidence of positive effects from working near higher-ability peers. Our estimates show that increasing the average of co-worker ability by 10 percent increases ownproductivity by about 0.5 percent. We find nonlinearities in the magnitude of peer effects across the distribution of own-ability: peer effects are the largest for the lowest ability workers. Since workers receive piece-rates and there is no team production, peer effects in our setting are not driven by production or compensation externalities. In additional analysis, we find evidence against learning or worker socialization as mechanisms. Results from an incentivized choice experiment suggest instead that peer effects in this context are driven by co-workers as a source of “motivation.” When given a choice to be re-assigned, the majority of workers want to be assigned to be near a fast (high-ability) coworker, even if switching is assigned an explicit cost. In open-ended survey responses, workers with demand for high-ability peers state that working near faster peers provides motivation to work harder.

“Pay Me Later: A Simple Employer-based Saving Scheme” (with Lasse Brune and Eric Chyn)

Workers in developing countries often lack good savings options. We study a no-frills employer-based savings technology that piggybacks on existing payroll infrastructure to provide a safe and convenient method to save up for lumpy expenditures. Partnering with an agricultural employer in Malawi we randomize offers to workers to defer part of their wages for three months, at zero interest, to receive a lump sum payout at the end of the main season. We find that the savings scheme has initial high take-up, high usage, and high repeat take-up. Take-up of the product changes behavior and outcomes: total savings in the treatment group increase over the implementation period; treatment workers have higher labor supply, a higher rate of large purchases, and higher asset holdings three months after the end of the intervention. We show that the seasonal timing is not crucial for take-up. Similarly, restrictions of access to accumulated funds have limited impact on take-up at the margin. In contrast, the disbursements of savings in a lump sum and the automatic regular deductions are key ingredients for the success of the scheme. 

“Teacher Effectiveness in Africa: Longitudinal and Causal Estimates” (with Julie Buhl-Wiggers, Jason T. Kerwin, Rebecca Thornton, and Jeffrey A. Smith)

This paper presents the first estimates of teacher effectiveness from Africa, using longitudinal data from a school-based RCT in northern Uganda. Exploiting the random assignment of students to classrooms within schools, we estimate a lower bound on the variation in teacher effectiveness. A 1-SD increase in teacher effectiveness leads to at least a 0.14 SD improvement in student performance on a reading test at the end of the year. Using detailed survey and classroom observation data, we find no detectable correlation between teacher effectiveness and teacher characteristics, but do find evidence that more effective teachers have more structured lessons and more active students. We find that providing teacher training and support increases the variation in teacher effectiveness.

“Enumerator Knowledge Effects in Subjective Expectation Elicitation: Evidence from a Randomized Field Experiment”

Subjective expectations about probabilities and the distributions of variables play a central role in modeling economic behavior. Direct elicitation of subjective beliefs via surveys is an increasingly popular tool, and recent research has shown that this is feasible even in low-income and low-numeracy settings. However, the enumerated surveys commonly used in developing countries have a potential weakness: respondents’ recorded beliefs may be affected by the enumerators’ knowledge about the belief questions. I show the importance of this issue using a randomized experiment that used enumerators to implement an information treatment. Reported beliefs are significantly shifted by the enumerators’ knowledge, decreasing by about 0.3 SD of the initial belief distribution. I discuss several mechanisms that may drive this phenomenon, including how the change in knowledge may have affected “probing” that enumerators did to encourage guesses when a respondent said they did not know the answer. These particular results are specific to my experiment; however, given the disparities in education levels between enumerators and respondents in typical developing-country surveys, the issue of enumerator knowledge contamination of subjective expectation data may be widespread. I suggest corrections for this issue from the perspectives of enumerator recruiment, survey design, experiment setup, and data analysis.