Calendrier du 17 avril 2023
Econometrics Seminar
Du 17/04/2023 de 17:30 à 18:45
URA Takuya (UC Davis)
Slow Movers in Panel Data
écrit avec Co-author: Yuya Sasaki
Panel data often contain stayers (units with no within-variations) and slow movers (units with little within-variations). In the presence of many slow movers, conventional econometric methods can fail to work. We propose a novel method of robust inference for the average partial effects in correlated random coefficient models robustly across various distributions of within-variations, including the cases with many stayers and/or many slow movers in a unified manner. In addition to this robustness property, our proposed method entails smaller biases and hence improves accuracy in inference compared to existing alternatives. Simulation studies demonstrate our theoretical claims about these properties: the conventional 95% confidence interval covers the true parameter value with 37-93% frequencies, whereas our proposed one achieves 93-96% coverage frequencies.
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Paris Migration Economics Seminar
Du 17/04/2023 de 15:00 à 18:30
site Ulm du Collège de France
Tom Raster (PSE)
Liam Wren-Lewis (PSE)
Mathilde Emeriau (LSE)
Régulation et Environnement
Du 17/04/2023 de 12:00 à 13:15
Salle R1-09, Campus Jourdan, 75014 Paris
DECAROLIS Francesco (Bocconi)
*Competition and Defaults in Online Search
Promoting and maintaining competition in the online markets dominated by few, large platforms has been an elusive quest for governments and their competition authorities. In
this study, we offer the first systematic assessment of the quantitative effects of a series of
interventions taken across countries to curb Google’s dominance in search by limiting its use
as the default option. By exploiting the timing with which such interventions occurred in the
European Economic Area, Russia, and Turkey relative to control group countries, we study how
changes to the default settings on mobile devices impacted the penetration of different search
engines. Our findings show that in all of these three cases, the interventions were effective in
reducing the market share of Google. The causal impact of the public intervention amounts to
less than 2 percentage points in the European Economic Area, 7 percentage points in Russia,
and 12 percentage points in Turkey. These differences are driven by the nuances of the specific
interventions such as the size of the targeted group of users, local market characteristics, and
remedy designs.