Industrial Organization, Quantitative Marketing

Regulating Privacy Online: An Economic Evaluation of the GDPR (American Economic Journal: Economic Policy, 2024)

Abstract: Modern websites rely on personal data to design better content and to market themselves. The European Union’s General Data Protection Regulation (GDPR) was intended to make access to such personal data much more difficult, with the goal of protecting user privacy. We examine the GDPR's impact on website pageviews and revenue for 1,084 diverse online firms using data from Adobe's website analytics platform. Using a panel differences approach, we find a reduction of approximately 12% in both EU user website pageviews and website e-commerce revenue recorded by the platform after the GDPR's enforcement deadline. To understand the policy's impact, we must separate the GDPR's effects on real outcomes from its impact on data recording. We derive informative bounds on both components by first examining site-usage patterns of selected users that we continue to observe post-GDPR. We bound changes to data recording, attributed to users opting-out of data collection, to be between 4% and 15%. This implies that at least 7% of our GDPR estimates (0.8% of total) arise from the consent effect on data recording. We then find larger effects on traffic from email and display ad marketing channels—specific targets of the GDPR. We conclude that at least 8% of our GDPR estimates (0.4% of total) arise from the GDPR's real effect on marketing alone. However, we do not find evidence that consent interfaces dissuade users from browsing sites. 

Privacy & Market Concentration: Intended & Unintended Consequences of the GDPR  (Management Science, 2023 - Featured Article)

Abstract: We show that websites' vendor use falls after the European Union's General Data Protection Regulation (GDPR), but that market concentration also increases among technology vendors that provide support services to websites. We collect panel data on the web technology vendors selected by more than 27,000 top websites internationally. The week after the GDPR's enforcement, website use of web technology vendors falls by 15% for EU residents. Websites are more likely to drop smaller vendors, which increases the relative concentration of the vendor market by 17%. Increased concentration predominantly arises among vendors that use personal data such as cookies, and from the increased relative shares of Facebook and Google-owned vendors, but not from website consent requests. Though the aggregate changes in vendor use and vendor concentration dissipate by the end of 2018, we find that the GDPR impact persists in the advertising vendor category most scrutinized by regulators. Our findings shed light on potential explanations for the sudden drop and subsequent rebound in vendor usage. 

Designing Monitoring Programs, 2023 (Draft available upon request)

Abstract: I study the design of voluntary consumer monitoring programs at a large U.S. insurer using data from almost 8 million unique drivers. Monitoring technology tracks driver behaviors and provides performance incentives for improved driving, in the form of discounts on future premiums. The profitability and welfare of these programs depend on who participates (driver selection) and how much drivers respond to performance incentives by reducing risk (moral hazard). I am able to separate these two mechanisms by leveraging unique variation in both performance and participation discounts. Using regression-discontinuity designs, I document that drivers respond to performance incentives by reducing accident risk by approximately 0.6%, on average – or 10% of the mean accident risk in my sample. These results inform a structural model that accounts for selection and moral hazard. The model suggests modest welfare gains due to limited participation. I then use the model to examine counterfactual incentive designs that highlight a key trade-off for program design: increasing driver participation comes at the cost of stronger performance incentives. My results highlight how monitoring programs can be used by firms to screen risky consumers and incentivize risk reduction.

Generative AI & Creative Goods: Market Expansion, Crowd-Out, and Copyright, 2025 (Revision Requested, Quarterly Journal of Economics)

Abstract: We study how generative artificial intelligence (GenAI) affects creative goods markets using data from a large stock images marketplace. In December 2022, the platform announced it would allow artists to sell GenAI-produced images, subject to two conditions: all GenAI images must be labeled, and GenAI would be prohibited in certain markets. We exploit this policy variation using a difference-in-differences design. We estimate a 136% increase in image production and 47% increase in active artists, accompanied by a 15% decline in non-GenAI production and 29% decline in non-GenAI active artists. On the demand side, total sales increase by 82%, but non-GenAI sales fall by 28% and non-GenAI sales rates decline by 5%. We use image embeddings to develop novel measures of image quality, characteristics, and market composition. We find that quality increases by 10% overall and 2% for non-GenAI content, suggesting low-quality non-GenAI artists exit. Our product characteristic measures indicate that GenAI production is heavily concentrated in characteristic space, potentially limiting the value of these images to the market. Non-GenAI production responds to GenAI by differentiating into niches. Our results suggest that GenAI can lead to market expansion and quality improvements, but substantially crowds out non-GenAI production—a finding with direct implications for copyright policy and the longer-run sustainability of original creative work.

1. Technology adoption and experimentation: evidence from GenAI w/ Tai Lam and Jason Zhao

2. The welfare implications of privacy online: evidence from a large scale field experiment w/ Guy Aridor

3. Will the market provide truth? Sycophancy and human capital development in the age of AI w/ Rafael Jimenez-Duran and Giulia Caprini

4. Merging intermediaries: evidence from ad-tech w/ Olivia Natan and Tesary Lin