Moritz Poll

Economist – PhD Student at Brown University

Welcome to my website. I am a PhD student at the Economics Department of Brown University. I was a research assistant at Princeton University and the Busara Center. I received my MPhil in Economics from the University of Oxford and a BSc Economics from Maastricht University. Below you can find my CV, a working paper as well as ongoing projects and papers I have contributed to as a research assistant.

Curriculum Vitae

Last updated 13 January 2020
CV Moritz Poll.pdf

Research Spotlight

Network Coordination: Rural Market Days

Abstract: Market days are the pulse of rural economic and social life in many parts of the world. They are a way of spatially and temporally aggregating thin market demand and supply to ameliorate food security and price volatility in poor regions. Market days are also a complex coordination game of assortative coordination (everybody trying to be in the same place at the same time) and non-assortative coordination (every village trying to have a different market day to its neighbors in order not to compete for participants). Fundamentally, coordination of markets determines who participates where and when in market exchange. If neighboring cities compete over buyers and sellers on the same day of the week, the resulting dispersed market exchanges will suffer price volatility and unsteady product variety. This can hamper growth in the best of times, but in the worst of times it will deepen food insecurity and economic crisis. Understanding how the coordination works and where it fails can guide the way to making profound changes in poor people's lives. Despite the fact that market days are an age-old feature of economic activity and human civilization, their coordination has not systematically been investigated. The coordination of these markets has an important social impact as it determines who meets on a regular basis, how social cliques and clusters form, within which groups/circles information diffuses or epidemics spread. Coordinated markets are a blueprint for the human networks that are likely to form through market participation and that facilitate knowledge diffusion and social learning. They also form the environment in which consumers and producers engage in costly search for one another.

Working Papers

Robust results in the presence of treatment interactions: The case of unconditional cash transfers

With Johannes Haushofer

Abstract: Recent contributions to the analysis of randomized experiments have shown that cross-randomizing several treatments can lead to small cell sizes, which can result in distorted treatment effect estimates. In addition, it has been suggested that failure to include interaction terms in regressions may also bias results. In light of these concerns, we re-evaluate a large study of unconditional cash transfers in Kenya with three cross-randomizations (recipient gender, transfer magnitude and timing). To circumvent the failure of asymptotic results in small cells, we first re-estimate the treatment effects of the study using randomization inference,bootstrapping, and a jackknife method. The results are very similar to those obtained with conventional asymptotic methods. Second, we show that in the class of experiments which assign multiple versions of the same treatment, rather than several independent treatments, inclusion of interaction terms does not yield“pure” treatment effects, but rather treatment effects for particular subgroups,which are not generally estimands of interest. Finally, we quantify the possible bias introduced by slight imbalances in cell sizes generated by randomization,and suggest a simple re-weighting to correct for it.

UCT Factorial Design Robustness

Work in Progress

The Effect of Stress on Inter-Ethnic Cooperation

With Johannes Haushofer, Sara Lowes, Nathan Nunn and Nancy Qian

In an earlier study at the Busara Center for Behavioral Economics, Berge et al. (2015) do not find evidence of ethnic/tribal preference in a large urban population in Nairobi for behavioral games such as the Dictator Game, the Choose Your Dictator Game or the Public Goods Game. In Kenya where tribal cleavages dominate the political landscape, this is a surprising finding. We hypothesize that this might be due to low levels of stress in the laboratory and conduct an experiment where randomly half of the 1800 participants are administered a small dosage of hydrocortisone, the equivalent of the cortisol hormone, while the other half receives a placebo pill. Participants play several rounds of the Dicator Game, the Choose Your Dictator Game and the Trust Game with cues to the ethnicity/tribe of the other player. Cortisol levels of participants are measured in between each game. I was involved in study design, preparation and will be running the imminent execution of the study as well as data analysis.

Forced idleness as screening device and its consequences

With Reshmaan Hussam and Josh Dean

The Non-Monetary Value of Work

With Reshmaan Hussam and Ingvild Skarpeid

Abstract: Communities with significant proportions of young unemployed men are often regarded as breeding grounds for crime and violence. This project seeks to understand the elementary mechanisms driving this association. What makes idleness so dangerous? Beyond serving as a source of income, how do individuals in impoverished, high-unemployment communities experience employment? We run a randomized control trial in the Kibera slum of Nairobi. We set up an employment program, in which we vary and measure employees’ relative valuations for three non-monetary dimensions of work: busyness (as opposed to idleness), agency (as opposed to subjugation) and purpose (as opposed to meaninglessness). Our experiment further allows us to estimate how these non-monetary valuations evolve with the experience of the newly employed. We then conduct a second randomized experiment that probes the role of idleness in exacerbating past trauma and motivating future risk-taking behavior.

Displacement in the Lab

With Reshmaan Hussam

Abstract: Among the well-documentedmajor consequences of forced displacement are injury and loss of life, disruption of social and economic networks and skill erosion through idleness. But there might a less tangible consequence stemming from the disruption of habits and perturbations in the habitual environment. This study simulates the experience of involuntary displacement in the context of a laboratory to understand how one’s environment impacts seemingly orthogonal dimensions of decision-making. In particular, we ask: how do unanticipated changes in strategically irrelevant dimensions of an environment affect behavior?

Discounting Gains and Losses

With Pamela Jakiela and Johannes Haushofer

Abstract: We ask what predictions different standard models of expected or reference-dependent utility make when we are deciding about losses rather than gains – a frequent occurrence in a poor person's life with potential for systematic biases – and whether data we collected on this can falsify some of these models.

Self-Defying Measurement

Abstract: Taking a measurement can influence the measurement itself. This is not only a statement about salience and experimenter demand under which subjects in a research project are aware of the behavior the researcher would like to see and act accordingly. In this project I am concerned with the notion that mental states such as arousal, boredom, primes, affect or cognitive load are themselves affected by the way they are measured.

Networks in Forced Migration

With Raphael Veiel

Abstract: We present a model of the formation and development of social networks of refugees and their host communities in a forced displacement context. Agents trade off the benefits of exerting effort in the economic and social sphere of their host society thus providing micro-foundations for measures of attachment to a location. By allowing both hosts and hosted to coordinate the formation of network connections, we clarify dimensions of social and economic selectivity such as integration and economic outcomes in migration choices. The integration of forced migrants into the social and economic life of their host country and communities as well as its impact on decision making of displaced populations is of vital interest to policy makers. We integrate this mechanism into the modular structure of a model of forced migration decision making and illustrate how endogenizing network dynamics can enrich selectivity analysis, predictions and counterfactual analysis.

Research Assistance

Building Resilient Health Systems: Experimental Evidence from Sierra Leone and the 2014 Ebola Outbreak

For Oeindrila Dube, Johannes Haushofer, Bilal Siddiqi, Darin Christensen and Maarten Voors

Developing countries are characterized by high rates of mortality and morbidity. A potential contributing factor is the low utilization of health systems, stemming from the low perceived quality of care delivered by health personnel. This factor may be especially critical during crises, when individuals choose whether to cooperate with response efforts and frontline health personnel. We experimentally examine efforts aimed at improving health worker performance in the context of the 2014–15 West African Ebola crisis. Roughly two years before the outbreak in Sierra Leone, we randomly assigned two accountability interventions to government-run health clinics – one focused on community monitoring and the other gave status awards to clinic staff. We find that over the medium run, prior to the Ebola crisis, both interventions led to improvements in utilization of clinics and patient satisfaction with the health system. In addition, child health outcomes improved substantially in the catchment areas of community monitoring clinics. During the crisis, the interventions also led to higher reported Ebola cases, as well as lower mortality from Ebola – particularly in areas with community monitoring clinics. We explore three potential mechanisms: the interventions (1) increased the likelihood that patients reported Ebola symptoms and sought care; (2) unintentionally increased Ebola incidence; or (3) improved surveillance efforts. We find evidence consistent with the first: by building trust and confidence in health workers, and improving the perceived quality of care provided by clinics prior to the outbreak, the interventions encouraged patients to report and receive treatment. Our results suggest that accountability interventions not only have the power to improve health systems during normal times, but can additionally make health systems resilient to crises that may emerge over the longer run.

Main paper, Companion Paper (AEA P&P), Non-technical summary

Media Coverage: New York Times, IPA, CBS

The Shape of Forgetting

For Johannes Haushofer

I conducted analysis for a project on forgetting and the cost of keeping track. In several experiments, participants in Kenya had the opportunity to earn money if they remembered to contact the Busara Center for Behavioral Economics on a certain day in the future. They could trade off higher rewards in the more distant future as well as reminders. We developed an algebraic representation for a forgetting function over time both objectively as well as through participants' subjective valuation. A working paper is in progress.

Multi-Country Economic Opportunity Assessment – Jobs Make The Difference

With Jason Pronyk, Daniel Egel, Susan Razzaz and Shelly Culbertson

We analyze the employment opportunities for Syrian IDPs and refugees in Syria, Jordan, Lebanon, Iraq, Turkey and Egypt. Full report under https://www.jobsmakethedifference.org/

Put to rest

The Timing of Return Migration after Conflict (Master's Thesis)

Abstract: Who returns after fleeing a conflict and how do forced migrants decide when to return? Return migration is selective whenever the choice between staying and returning is deliberate. Such selection may introduce bias when estimating the impact of return migration on refugees’ welfare, their destination country or country of origin. This paper recognizes the agency of forced migrants when it comes to their decision to return, despite their involuntary displacement. It constructs a model of return timing choice capable of producing plausible return patterns. A key motive of both return and non-return is individual-specific locational preference. The paper proposes a GMM-estimator for the preference distribution across the population which is vital to understanding return migration flows and to undertaking counterfactual analysis. It can be used to gauge how likely someone is to return or what impact a policy intervention might have on return decisions.

The Timing of Return Migration after Conflict

Dichotomous Effects of Positive and Negative Growth on the Income of the Poor (Bachelor's Thesis)

Abstract: Who returns after fleeing a conflict and how do forced migrants decide when to return? Return migration is selective whenever the choice between staying and returning is deliberate. Such selection may introduce bias when estimating the impact of return migration on refugees’ welfare, their destination country or country of origin. This paper recognizes the agency of forced migrants when it comes to their decision to return, despite their involuntary displacement. It constructs a model of return timing choice capable of producing plausible return patterns. A key motive of both return and non-return is individual-specific locational preference. The paper proposes a GMM-estimator for the preference distribution across the population which is vital to understanding return migration flows and to undertaking counterfactual analysis. It can be used to gauge how likely someone is to return or what impact a policy intervention might have on return decisions.

Dichotomous Effects of Positive and Negative Growth on the Income of the Poor