Jan Sonntag

Welcome to my website! I am a PhD candidate at Sciences Po's Department of Economics. I am interested in applied microeconomics, specifically behavioral economics and production networks. My supervisor is Emeric Henry.

More about my research


Most of my papers are still work in progress - please feel free to reach out to discuss a project or obtain early drafts.

Measuring Image Concern

With Emeric Henry

R&R Journal of Economic Behavior and Organization
It is now well documented that individuals tend to change their behavior when their actions are observed by others. Yet there is no systematic way of measuring this dimension of preferences at the individual level. In this paper, we propose a novel experimental game to measure individual sensitivity to social image. We document substantial heterogeneity in the level of image concern and assess its drivers and consequences. While few socioeconomic characteristics seem to have explanatory power, members of ethnic minorities appear less sensitive to being observed by a another member of a minority group. Finally, we show that more image concerned individuals tend to be more selfish and find evidence suggesting that they try to avoid situations where their actions might be observed.
Download the latest draft

Vertical Foreclosure in the Global Production Network

With Johannes Boehm

Work in Progress
This paper studies the prevalence of market foreclosure using a novel dataset on U.S. and international buyer-seller relationships, and across a large range of industries. We find that relationships are more likely to break when a supplier vertically integrates with one of the buyers' competitors than when it vertically integrates with an unrelated firm. We establish causality using the prevalence of past vertical integration among related parties as an instrument. Foreclosure is more prevalent when suppliers have more market power. Furthermore, we find a substantial drop in performance among foreclosed firms.

Social Norms and the Prevalence of Hate-Speech: Evidence from Facebook

Work in Progress - More details to come soon


You can find my CV here.

Contact Details

Sciences Po - Département d'économie, 28 Rue des Saints-Pères, 75007 PARIS

jan dot sonntag [at] sicencespo dot fr