CSSO Speaker Series: Giada Di Stefano
Giada Di Stefano
Professor of Strategy, Bocconi University
The Experts and the Crowd? Heterogeneity in Status and the Behavior of Amateur Reviewers
Date: Friday, April 17, 2026
Time: 10:30 AM - 12:00 PM
Location: Bronfman building, room 301
Abstract
Nowadays, amateur reviewers and professional critics coexist in many markets and express their opinions on the same producers and offerings. To what extent should we expect the evaluations provided by consumers to conform to those provided by professional critics? And are all consumers equally subject to such conformity pressure? To examine these questions, we exploit a fortuitous partnership between Michelin, the editor of the most prestigious restaurant guide, and TripAdvisor, a prominent aggregator of consumer reviews for the restaurant industry. As a result of this partnership, the TripAdvisor pages of restaurants evaluated by the Michelin Guide were updated with a Michelin badge under the restaurant name and a direct link to the evaluation by Michelin inspectors. Using a difference-in-differences approach, we examine changes in reviews posted on TripAdvisor before and after the appearance of the Michelin evaluation relative to reviews posted on Yelp, a similar platform that did not introduce any Michelin-related information. Our results reveal that amateur reviewers significantly changed their evaluations when the opinion of experts became more salient. The change was reflected in both the form and substance of their reviews, with differential treatment effects depending on the status of the amateur evaluators on the review platform.
