Calendrier du 12 juin 2023
Roy Seminar (ADRES)
Du 12/06/2023 de 17:00 à 18:15
Salle R1-09, Campus Jourdan, 75014 Paris
SHAHANAGHI Sara (TSE)
*Competition and Herding in Breaking News
I present a dynamic model of breaking news. News firms are rewarded for reporting before their competitors but also for making reports that are credible to consumers. Errors occur when firms fake, reporting a story despite lacking evidence. While errors occur in equilibrium even under a monopoly, competition and observational learning exacerbate errors and give rise to rich dynamics in firm behavior. Competition intensifies faking by engendering a preemptive motive, but the haste-inducing effect of preemption is endogenously mitigated by gradual improvement in report credibility over the course of a news cycle. Meanwhile, observational learning causes existing errors to propagate through the market. This is driven by a copycat effect, in which one report triggers an immediate surge in faking by others. This behavior is consistent with herding on the decision to report a story as well as herding on the timing of reports.
Econometrics Seminar
Du 12/06/2023 de 16:00 à 17:15
Zoom seminar
MASTEN Matt (Duke University)
Assessing Omitted Variable Bias when the Controls are Endogenous
écrit avec Co-authors: Paul Diegert and Alexandre Poirier
Omitted variables are one of the most important threats to the identification of causal effects. Several widely used approaches, including Oster (2019), assess the impact of omitted variables on empirical conclusions by comparing measures of selection on observables with measures of selection on unobservables. These approaches either (1) assume the omitted variables are uncorrelated with the included controls, an assumption that is often considered strong and implausible, or (2) use a method called residualization to avoid this assumption. In our first contribution, we develop a framework for objectively comparing sensitivity parameters. We use this framework to formally prove that the residualization method generally leads to incorrect conclusions about robustness. In our second contribution, we then provide a new approach to sensitivity analysis that avoids this critique, allows the omitted variables to be correlated with the included controls, and lets researchers calibrate sensitivity parameters by comparing the magnitude of selection on observables with the magnitude of selection on unobservables as in previous methods. We illustrate our results in an empirical study of the effect of historical American frontier life on modern cultural beliefs. Finally, we implement these methods in the companion Stata module regsensitivity for easy use in practice.
Texte intégral
Paris Migration Economics Seminar
Du 12/06/2023 de 12:30 à 13:30
Salle R2.20, campus jourdan
ZENOU Yves (Monash University)
Ethnic Mixing in Early Childhood: Evidence from a Randomized Field Experiment and a Structural Model
We study the social integration of ethnic minority children in the context of an early childhood
program conducted in Turkey aimed at preparing 5-year-old native and Syrian refugee children
for primary school. We randomly assign children to groups with varying ethnic composition
and find that exposure to children of the other ethnicity leads to an increase in the formation of
interethnic friendships. We also find that the Turkish language skills of Syrian children are better
developed in classes with a larger presence of Turkish children and that these positive effects
persist into primary school. We then develop a model of language acquisition and friendship
formation, with language skills acting as a key input in the formation of interethnic friendships.
Structural estimation of the model suggests that interethnic exposure reduces the share of own-ethnicity
friends (homophily) and has a non-monotonic effect on the propensity to form own-ethnicity
friendships beyond what would be expected given the size of the group (inbreeding
homophily). Counterfactual analysis indicates that the language skills of Syrian children are as
important as ethnic bias for the integration of Syrian children.
Régulation et Environnement
Du 12/06/2023 de 12:00 à 13:15
R1-15, Floor 1 - 48, bvd Jourdan 75014 Paris
GAUTHIER Stephane (PSE)
Targeting taxes on local externalities
We study optimal consumption taxes when the magnitude of an
externality varies with the individuals who cause it but taxes must be
anonymous, e.g., urban fuel consumers imply greater damages than
rural ones but both face the same fuel tax. We provide a condition
for the validity of the targeting principle, according to which external
concerns only fall on the tax on the externality generating commodity.
When this condition holds, one can identify the equity/efficiency and
environmental contributions to this tax.
An illustration on France
suggests that Pigovian considerations explain most of the fuel tax.
GSIELM (Graduate Students International Economics and Labor Market) Lunch Seminar
Du 12/06/2023
Maison des Sciences Economiques, Salle 116
ABDELSALAM Farida (CES, Paris-1)
The effect of input-trade liberalization on firms' borrowings
écrit avec Maris Bas (Paris 1)
Trade liberalization creates incentives for firms to upgrade domestic and foreign technology, embodied in imported intermediate and capital goods, which play a central role in the economic growth of developing countries. Firms require access to financial resources to pay the fixed cost of technology upgrading and sourcing foreign inputs from abroad. This paper investigates the micro-economic effects of input-trade liberalization on firms’ demand of external finance. Relying on firm-level data during India’s trade liberalization episode in the early 1990s, we present novel evidence on the relationship between exogenous changes in input tariffs across industries over time and within-firm changes in borrowings. We demonstrate that firms sourcing inputs from abroad and producing in industries that have experienced greater input tariff reductions experienced a higher increase in borrowings. This empirical finding is robust to alternative specifications that control for other reforms, and industry and firm characteristics.