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My name is pronounced: Day-vee Wex

Welcome! I am a sixth-year Ph.D. student in the Department of Economics at the Massachusetts Institute of Technology (MIT). My research is in development economics and organizational economics, focusing on technology and firms in lower-income countries, particularly in West Africa.

My dissertation explores how digital technologies reshape economic relationships and contract structures within and between firms, and uncovers the key drivers and barriers to their adoption.

Over the past eight years, I have conducted research projects in Côte d'Ivoire, Ethiopia, Senegal, and Togo.

I am on the 2024-25 Academic Job Market. [CV] - houeix@mit.edu

Research Papers

  1. Asymmetric Information and Digital Technology Adoption: Evidence from Senegal (Job Market Paper), Media Coverage: RFI, Draft Coming Soon
    Abstract

    The rise of digital technologies in the workplace can reduce information asymmetry and reshape employer-employee contracts: by making worker actions more observable, these technologies help mitigate moral hazard. However, employees may resist adoption if they fear losing informational rent. I explore this trade-off through two field experiments—guided by contract theory—where I introduce digital payments to the Senegalese taxi industry in partnership with the country's leading payment company. In the first experiment, I randomize access to digital payments for drivers (employees) and, within this group, further randomize the extent to which transactions are observable by taxi owners (employers). I find that digital payments reduce drivers' cash-handling costs by about half and serve as effective monitoring tools for taxi owners. Digital transaction observability enhances driver effort (+29%) as measured through mystery passengers, induces more salaried contracts (+18%), and increases the duration of the driver-owner relationships (+17%). However, 50% of drivers—primarily the least productive and poorest—decline to adopt when transactions are observable. The second experiment shows that the adoption rate doubles when drivers are assured that their transactions will not be observable by the owners. I develop a theoretical framework and use the experimental variations to structurally estimate the welfare impacts of policy counterfactuals. I show that mandating technology adoption may reduce welfare compared to the status quo, while removing payment observability broadens adoption but maintains moral hazard. My findings demonstrate that the information embedded in digital technologies can hinder their adoption when individuals within a firm have conflicting incentives for observability, with important implications for both technology adoption and firm growth.

  2. Nationwide Diffusion of Technology Within Firms’ Social Networks, Media Coverage: Liberation
    Abstract

    I conduct a randomized experiment to study the nationwide technology diffusion of a new digital payment technology in Senegal. By leveraging two novel sources of network data—mobile money transactions and anonymized phone contact directories covering the near universe of the adult population in Senegal—I causally identify three sets of adoption spillovers from taxi firms randomized to receive early access to the technology: intra-industry among taxi firms; inter-industry between taxi drivers and other small businesses; and inter-regional spillovers from the capital city to businesses in other urban centers. I show that spillovers go beyond strategic complementarities, reflecting social learning within firms' social networks, driven by social ties and remote interactions.

  3. Relational Frictions Along the Supply Chain: Evidence from Senegalese Traders (with Edward Wiles), Draft Coming Soon
    Abstract

    Search and trust frictions have historically made it hard for small firms in lower-income countries to buy inputs from foreign markets. The growth in smartphone ownership and social media usage has the potential to alleviate these barriers. We run a field experiment leveraging these technological tools to provide exogenous variation in search and trust frictions in a large international import market. The design is informed by a dynamic relational contracting model featuring sequential search for suppliers and trust frictions in the form of adverse selection and moral hazard. In our search treatment, we connect a randomly selected 80% of 1,862 small garment firms in Senegal to new suppliers in Turkey. We then cross-randomize two trust treatments that provide additional information about the types and incentives of these new suppliers. Alleviating search frictions is sufficient to increase access to foreign markets: in all treated groups, firms are 25% more likely to have the varieties a mystery shopper requests and the goods sold are 32% more likely to be high quality. However, the trust treatments are necessary for longer-term impact: these groups are significantly more likely to develop the connections into relationships that persist beyond the study. These new relationships lead to increases in medium-run profit and sales, particularly among wholesalers in the upper tail. Finally, we use the treatment effects to estimate the model and evaluate counterfactuals where we set various combinations of the frictions to zero, finding that the largest gains come from eliminating adverse selection.

  4. Financial Inclusion and Rural Electrification: Evidence from Togo (with Paul Brimble, Axel Eizmendi Larrinaga, and Toni Oki)
    Abstract

    Most people in sub-Saharan Africa still lack access to electricity, despite rural electrification being a policy priority. We provide evidence that high transaction costs, particularly transportation expenses to access mobile money agents for bill payments, are a key friction for rural households. In rural Togo, these costs account for 28% of solar electricity-related expenditures, rising to 43% in more remote areas. To assess the impact of transaction costs on policy outcomes, we analyze the staggered rollout of two nationwide policies in Togo in 2019: a solar home system subsidy and an expansion of mobile money agents. The subsidy, which nearly halves electricity prices, more than doubles adoption rates. However, the effects vary significantly: households with lower transaction costs—those with direct access to mobile money agents—adopt at much higher rates and decrease the number of payments they make in response to the price reduction. The mobile money agent expansion led to nearly a threefold increase in adoption, an effect similar to that of the subsidy. By reducing transaction costs, these policies enable bulk purchases and lessen the need for frequent payments. Our findings highlight the complementary roles of subsidies and financial inclusion in improving rural electrification and access to essential services.

  5. Eliciting Poverty Rankings from Urban or Rural Neighbors: Methodology and Empirical Evidence (with Pascaline Dupas and Marcel Fafchamps), Revised August 2024 for Quantitative Economics
    Abstract

    We introduce a novel approach for eliciting relative poverty rankings that aggregates partial orderings reported independently by multiple neighbors. We first identify the conditions under which the method recovers more accurate rankings than the commonly used Borda count method. We then apply the method to secondary data from rural Indonesia and to original data from urban Cote d’Ivoire. We find that the aggregation method works as well as Borda count in the rural setting but, in the urban setting, reconstructed rankings from both the pairwise and Borda count methods are often incomplete and sometimes contain ties. This disparity suggests that eliciting poverty rankings by aggregating rankings from neighbors may be more difficult in urban settings. We also confirm earlier research showing that poverty rankings elicited from neighbors are correlated with measures of poverty obtained from survey data, albeit not strongly. Our original methodology can be applied to many situations in which individuals with incomplete information can only produce a partial ranking of alternatives.

Selected Work in Progress

  • Internal Migration, Remittances, and Networks: Evidence from Senegal (with Edward Wiles)
    Abstract

    We explore the relationship between internal migration, remittances, and financial and social networks in lower-income contexts, with a focus on Senegal. To establish new facts and causal evidence, we construct a unique dataset that links migration patterns to both remittance flows and social networks covering the near universe of Senegal's adult population, based on real-time GPS tracking of personal and business transactions and anonymized phone contact directories from the country’s largest mobile money provider. We use this dataset to document patterns of migration and remittance flows to a high degree of spatial and temporal precision, and to explore how financial and social networks affect—and are affected by—these patterns, especially in response to economic or environmental shocks.

  • Digitalization of Local Tax Collection in Côte d’Ivoire (with Pascaline Dupas)
    Abstract

    Low tax capacity hampers the ability of municipalities in Côte d’Ivoire, as in many other countries, to provide quality public services for their populations. We study the impacts of the nationwide rollout of a digital tax system, through which municipalities will move to entirely cash-less tax collection. We explore the impact on total tax revenue, size of the tax base, spending (including public good provision), and local government accountability.

Other Publications