Companies spend billions of dollars online for paid links to branded search terms. Measuring the effectiveness of this marketing spending is hard. Blake, Nosko and Tadelis (2015) ran an experiment with eBay, showing that when the company suspended paid search, most of the traffic still ended up...

We analyze a large-scale randomized field experiment in which a search engine varied the prominence of search ads for 3.3 million US users: one group of users saw the status quo, while the other saw a lower level of advertising (with prominence of search ads decreased). Revealed preference data...

Online display advertising is a hostile medium for field experiments. Display ad effects are tiny and necessitate large-scale experiments. The experimenter has limited control because ad exposure is jointly determined by advertisers, users, algorithms, and market competition. As such, online...

Measuring the causal effects of digital advertising remains challenging despite the availability of granular data. Unobservable factors make exposure endogenous, and advertising's effect on outcomes tends to be small. In principle, these concerns could be addressed using randomized controlled...

Yahoo! Research partnered with a nationwide retailer to study the effects of online display advertising on both online and in-store purchases. We use a randomized field experiment on 3 million Yahoo! users who are also past customers of the retailer. We find statistically significant evidence...

Keyword searches with brand names occur very commonly on search engines, which enables firms to infer not only when customers are searching for them, but also when customers are searching for their competitors. In other words, firms can generate traffic from search engine advertising by bidding...

“North” ads, or sponsored listings appearing just above the organic search results, generate the majority of clicks and revenues for search engines. In this paper, we ask whether the competing north ads exert externalities on each other: does increasing the number of rival north ads decrease...