Publications

We study the impact of the implementation of Apple’s App Tracking Transparency (ATT) framework on the Apple App Store ecosystem. We use comprehensive data on every app available in both the Apple App Store and Google Play Store ecosystems in the one year period around the implementation of ATT, and a difference in differences analysis to investigate whether the introduction of the privacy transparency framework affected the incentives for developers in the Apple ecosystem to create new apps, update their existing apps, or withdraw from the market. We also leverage data on the presence of Software Development Kits (SDK) in a select number of apps in each ecosystem to study how developers adapted specific functionalities in their products, such as the use of advertising platforms or payment systems. We find that the number of available apps in the Apple App Store ecosystem quickly recovers after an initial drop following the introduction of ATT. We do not find evidence suggesting that ATT has reduced developers’ interest in the Apple ecosystem relative to the Google ecosystem. When analyzing the use of SDKs by apps in genres that rely heavily on advertising before ATT, we find a reduction in the use of Ad Mediation SDKs, and, an increase in the use of authentication and payment SDKs. Our results suggest developers did not withdraw from the market after ATT and instead adapted to operate under the conditions of a more protective privacy framework.
Ask me for an early draft if interested

We construct a longitudinal data-set of news and media websites to study how online content providers adapted their responses to the GDPR over time, and whether restrictions on online tracking enforced by the regulation affected downstream outcomes such as the quantity of content those websites offer to their visitors and visitors’ engagement with such content. We find robust evidence of websites’ reactions to the GDPR in both the US and the EU. However, reactions differ between US and EU websites. We find a small reduction in average page views per visitor on EU websites relative to US websites near the end of the period of observation, but no statistically significant impact of the regulation on EU websites’ provision of new content, social media engagement with new content, and ranking in both the short-term and the long-term.
See below for working paper, and video of presentation at the FTC PrivacyCon’22.

This study analyzes how scientists on Twitter react to high-visibility events. Using a longitudinal sample of 17,157 scientists and a matching-based framework, why study how unusual visibility events affect users’ subsequent behaviors and long-term visibility on the platform.

We study the impact of increasing online intermediation in legacy industries. We motivate the empirical analysis with a duopoly model where an intermediary platform enables firms to attract consumers from competitors by offering them higher benefits. We show the intermediary can induce firm to join, even when they cannot expect benefits from joining. Additionally, as the popularity of the platform raises, it can extract a growing proportion of the benefits it creates. The analysis focuses on restaurants’ adoption of OpenTable in New York City. Results support the model predictions of cost pass-through to consumers of fees charged to restaurants, and no effect of adoption on restaurant survival.
See below for working paper and video of presentation at the StartML Workshop @ NeurIPS’21

We present the design and the pilot results of a large-scale field experiment on the economic impact of ad-blocking and anti-tracking technologies on consumers’ behavior and economic outcomes. The online advertising industry has often heralded the economic benefits of (targeted) online advertising. Its claims are juxtaposed by the privacy concerns associated with the vast number of ad-tech companies tracking and analyzing consumers’ online behavior – often without consumers’ awareness. We analyze the economic impact of ad-blocking and anti-tracking technologies, focusing on consumers’ online behaviors (such as browsing and shopping), and their ultimate purchasing outcomes (as measured by amounts of money spent online, product prices paid, time spent on product searching, and purchase satisfaction). In this paper, we describe the rationale and motivations behind our study; the experimental design and the instrumentation infrastructure we developed for the experiments; the results of three pilots of the study; and the plans for the complete data collection.
See below for working paper, and video of presentation at the Economics of Digital Services EODS Economics of Digital Services Inaugural Research Symposium.

We study firm performance in the semiconductor industry after the introduction of the integrated circuit, comparing the outcomes experienced by diversifying firms and new entrants across different clusters. Over the long term, succesful firms were disproportionately Spinoffs of leading firms, or diversifiers with a transistor background. New firms in Silicon Valley were more likely to enter at the technological frontier. However, over the long term, location had no significance on becoming a top producer.

We study firm entry and inventor mobility in the Semiconductor Industry. Our results show most of the increased inventor mobility in Silicon Valley is due to inventors moving from parents to spinoffs, or from incumbents to recent entrants. Incumbents in Silicon Valley don’t seem to benefit from the greater mobility of inventors in the cluster, as they don’t hire inventors at a higer rate than incumbents in other regions, while they lose many inventors that leave to join new firms.