We are grateful to Anlei Dong, Glenn Ellison, Chiara Farronato, Jingyi Guo, Paul Heidhues, Minha Hwang, Aadharsh Kannan, Widad Machmouchi, Markus Mobius, Sarah Moshary, Aviv Nevo, Michael Schwartz, Fiona Scott Morton, Steve Tadelis, Catherine Tucker, Mike Whinston, and audiences at Amazon, Charles River Associates, Chicago Booth, DMA and Beyond, NBER SI Digital Economics, Harvard-MIT IO Seminar, HBS Markets and Competition Conference, Northwestern Antitrust Conference, NYU Stern IO day, Paris School of Economics, Stanford SITE, Stanford Behavioral Seminar, University of Michigan, University of Zurich, Wharton, UVA, VIDE Seminar, Temple University, and TSE Economics of Platforms Seminar for helpful comments. We thank Chris Karr and Audacious Software for dedicated work on the Search Extension browser extension, and we thank Chiara Farronato and Andrey Fradkin for allowing Search Extension to use code developed for their work. We thank Shotaro Beppu, Jack Cenatempo, Juan Carlos Cisneros, Wonjoon Choi, Grace Coogan, Xingtong Jiang, Luca Moreno-Louzada, Sameer Nair-Desai, Shiqi Yang, and Wanxi Zhou for exceptional research assistance. We are grateful to the Sloan Foundation, the Sloan Research Fellowship, the Stanford Institute for Economic Policy Research (SIEPR), and the Business Economics and Public Policy Department at the Wharton School of the University of Pennsylvania for generous support. We also gratefully acknowledge Microsoft Bing for sharing data with us. The experiment was approved by the MIT Committee on the Use of Human Subjects (Protocol # 2308001088) and was registered in the American Economic Association Registry for randomized control trials under trial AEARCTR-0012884; the pre-analysis plan is available from https://www.socialscienceregistry.org/trials/12884. Disclosures: Allcott, Castillo, and Musolff have previously worked at Microsoft Research. Gentzkow has done litigation consulting for Google and has been a member of the Toulouse Network for Information Technology, a research group funded by Microsoft. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.
Matthew Gentzkow
I have been a paid consultant for Amazon and done economic consulting for Analysis Group and Compass Lexecon. Clients for this economic consulting work include large technology companies such as Facebook and Google. I have received compensation as a member of the Toulouse Network for Information Technology, a research group funded in part by Microsoft.
