Title: Liquid markets: allocating clean water to the rural poor

Title: Pricing, entry, and social learning

Abstract: I develop a two-period theoretical model to show how potential entry and competition in the future shapes the optimal learning speed for the Incumbent in period 1. As a result, the Incumbent might want to push the period 1 price beyond a static monopoly level if, a priori, the market is less optimistic; lower the price if the market is instead too optimistic.

Title: Privacy Preserving Signals

Abstract: A signal is privacy-preserving with respect to a collection of privacy sets, if the posterior probability assigned to every privacy set remains unchanged conditional on any signal realization. We characterize the privacy-preserving signals for arbitrary state space and arbitrary privacy sets. A signal is privacy-preserving if and only if it is a garbling of a reordered quantile signal. These signals are equivalent to couplings, which in turn lead to a characterization of optimal privacy-preserving signals for a decision-maker. We demonstrate the applications of this characterization in the contexts of algorithmic fairness, price discrimination, and information design.

Title: It Takes a Village: The Economics of Parenting with Neighborhood and Peer Effects

Title: Testing for identification in potentially misspecified linear GMM (joint with Zhaoguo Zhan)

This paper is still work in progress so there is not a paper to distribute yet.

Title: College Expansion and Skill Premium in Early Career.

Title: Nudging online grocery shoppers to buy more sustainable food.

Title: Campaigning Against Populism: Emotions and Information in Real Election Campaigns (with Cesi Cruz and Francesco Trebbi).

 Abstract:

Across the world, politics is dominated by populists who are adept at using new forms of campaigning to reach citizens directly and spread, often through emotional appeals, their ideology. The challenge for mainstream parties has been how to articulate policy platforms and campaign promises in this new context. In particular, do forms of campaigning used by populist politicians -- direct in-person appeals and emotional messaging -- work for programmatic and platform-based politicians as well? We implement a field experiment during the 2019 Philippine Senate election with a mainstream opposition party to explore the effectiveness of: (i) their door-to-door visits delivering policy platform information to assess the role of direct appeals; (ii) the addition of explicit emotional messaging in mediating these interactions. We show that direct appeals and emotional messaging foster increased engagement with the campaign in the short term, but that over time the in-person policy information is more relevant in driving vote choice for programmatic parties, even when facing populist incumbents. The treatments operated through a persuasion channel, as treated voters were more likely to know the party, more certain, and gave higher ratings to the party's quality and proposed policies.

Title to be advised.

Title: Strategic Ignorance and Information Design (with Thomas Wiseman)

Title: Building Central Bank Credibility: The Role of Forecast Performance

Title to be advised.

Title : Undergraduate Gender Diversity and the Direction of Scientific Research

Title: The Anatomy of Online Reviews: Evidence of Self-Selection from the Steam Store.

Abstract How good are reviews as signals of product quality for consumers? Using a data-set derived from the popular `Steam' gaming platform I investigate the self-selection of reviewers. A policy reform on Steam in 2019 both lowered the transaction cost of reviewing, with this randomly occurring within a game and reviewer's life cycle. I find that the new individuals elicited to review by the policy change are 4\% more likely to rate any game positively, leave 15\% shorter reviews and are less experienced both within and across games. This selection is heterogeneous across games, greatly affecting their rank order and while some sellers benefitted from the increase in selection, others did not. Overall, the policy reduced selection bias and improved the consumer's information set, but new reviewers were rated as less helpful by their peers, implying that more accurate review scores come at the cost of less helpful reviews.

Title: Persuasion with Limited Data: A Case-Based Approach

Title: Heterogeneous Predferences, Spousal Interaction, and Couples' Time-Use.

Title: Semidiscrete optimal transport maps: stability, limit theorems, and asymptotic efficency.

This is a joint seminar with Department of Statistics as part of the new joint Econometrics & Statistics seminar series.

Title : The Job Ladder: Inflation vs Reallocation (with Fabien Postel-Vinay)

Title to be advised.

Title: Who benefits from faster public transit?

Abstract: Fast public transit networks are widely believed to (i) reduce driving and its externalities, and (ii) reduce inequality by improving mobility for the urban poor. But are the transit improvements that are most effective at reducing driving also more equitable? Combining survey data with web-scraped counterfactual travel times for millions of trips across 49 large US cities, I estimate a model of travel mode and residential location choice. I characterize the heterogeneity across income groups and cities in commuters' marginal willingness to pay for access to faster transit and to increase their transit ridership. I find that higher-income transit riders sort more aggressively into the fastest transit routes and are, on average, willing to pay more for faster commutes. Improvements in transit speed are most effective at generating transit ridership and welfare gains where transit is already fast (relative to driving), in cities with a greater share of rail-based transit and where the gains are larger for higher-income commuters. Transit improvements benefit lower-income commuters more where transit is relatively slow, in cities with more bus transit, and where the overall marginal gains are small.

Title: Dynamic Screening: Why Weight isn't Volume

This paper is preliminary and incomplete

Title: Operator Learning in Macroeconomics

Abstract: This paper proposes a novel solution framework for the class of dynamic macroeconomic models with a continuum of heterogeneous agents and aggregate uncertainty. In these models, an agent's state variables include her individual state vector and a distribution function representing all agents' states, an infinite-dimensional object. Unlike the prevalent benchmark method that approximates the distribution function with a high-dimensional vector of simulated agents, this paper suggests the formulation of the policy function as an operator that maps between function spaces. The operator is parameterized by a cutting-edge neural network architecture known as the neural operator. This proposed framework offers significant computational advantages due to its three defining properties: discretization-invariance, permutation-invariance, and aggregation-sharing. The effectiveness of this approach is demonstrated by solving the Bewley-Huggett-Aiyagari model with aggregate uncertainty, a benchmark in computational economics literature. The proposed framework not only demonstrates computational efficiency as it manages tens of thousands of agents during simulations to precisely approximate the distribution function but also showcases its superior performance, achieving solutions with less than a one percent relative error in a shorter computational time compared to the benchmark method.

Title: Learning Before Testing: A Selective Nonparametric Test for Conditional Moment Restrictions

This seminar will be online via MS Teams.

Title: Skill Supply and the Organization of Production

Title to be advised.

Title: What happens when you tax the rich? – Evidence from South Africa

Abstract - Rising levels of income inequality and tight government budgets have spurred discussions in many developing nations about how to appropriately tax high-income earners. In this paper, we study taxpayer responses to an increase in the top marginal tax rate in South Africa drawing on exceptionally rich tax administrative data and a transparent empirical identification design. We establish that treated taxpayers strongly reduce their reported taxable income in response to the tax reform. Our preferred estimates suggest an elasticity of taxable income (ETI) of 1.1. Consistent with few deductions in the South African PIT system, adjustments are driven by changes in broad income – in particular investment income and other income components that are not subject to third-party reporting. While standard labor income remains unaffected, our evidence does point to real effects of the reform: Treated taxpayers attract fewer annual incentive and bonus payments after the reform. Consistent with this reflecting less effort provision by leading workers in South African firms, we find that businesses, which employ workers subject to the tax increase, experience a significant decline in business output after the reform.

 .

Two 30mins presentations:

No.1 Human Capital, Self-Insurance, and Marriage Uncertainty: Racial Differences in Female Labor Supply

Abstract: Racial difference in female labour supply has been a puzzle in both economics and sociology as it is found not explained by economics, demographic or family variables. This paper first shows that racial gap is driven by married Black women with high wages in the South returning to the labor market almost immediately after childbirth. Failed to find any contemporaneous covariates to explain the gap, I build a life cycle model of female labor supply, consumption, and savings with uncertainty in divorce shock. Only using the racial difference in marriage and divorce rates, the model is able to generate the same racial gap in child penalties as empirical estimates. The structural model illustrates that Black women stay in the labor market to prevent human capital from depreciation as a means to self-insure against future divorce shocks.

Link to paper https://warwick.ac.uk/fac/soc/economics/staff/jli/others/li_2022.pdf

No.2 Double Negative: Climate Change, Seasonality and Schooling

Abstract: Literature finds ambiguous or weak effects of annual average rainfall on schooling. This paper, however, demonstrates that rainfall has a significantly opposite effect on school enrollment, depending on the season in which it occurs. Increased precipitation in the dry season enhances schooling, while it reduces schooling in the wet season. Measuring rainfall annually cancels out the double negative impact, as climate change pushes precipitation in opposite directions between the two seasons. The paper calls for urgent policy measures for child protection in development against climate risks

Title: Optimal Indirect Regulation of Externalities

Title: The Effect of Mergers on Innovations (joint with Kaustav Das and Tatiana Mayskaya)

Abstract: We study the effect of a merger on R&D activity in a dynamic model in which there is uncertainty about the feasibility of innovation. Once an innovation has already taken place, the merger may block future innovations (cannibalization effect). The merger may increase the probability of the first innovation (appropriability effect). The merger may bring the first innovation forward in time (informational effect). The merger may increase innovation diversity (diversity effect).