UCL School of Management is delighted to welcome Professor Giada Di Stefano, Bocconi, to host a research seminar discussing: The experts and the crowd: The interplay between qualified rankings and consumer ratings’.

Abstract

• Abstract: As consumers gain their right to speak up through their contribution to online review platforms, an interesting question arises as to the extent to which these amateur evaluators will retain their original role of opinion-takers vis-à-vis professional critics. 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 ratings 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, showing the restaurant’s distinction in the guide. This change likely increased the salience of the expert evaluator’s opinion in the eyes of consumers without any change on the side of producers. Using a difference-in-differences approach, we examine changes in language and ratings of reviews posted on TripAdvisor before and after the appearance of the Michelin badge relative to reviews posted on Yelp, a competing review platform that was not affected by the partnership. Our results reveal that amateur evaluators significantly changed their reviewing style when expert evaluations became more salient. The change was reflected in both the form and substance of their online evaluations, with differential treatment effects depending on the status of the amateur evaluators on the review platform.