Value of Sharing Data

This paper analyzes whether advertisers would be better off using data that would enable them to target users more accurately if the only way they could use this data is by sharing the data with all advertisers. I present a wide range of theoretical results that illustrate general circumstances under which an advertiser can be assured that sharing data will make the advertiser better off. I then empirically analyze how sharing data would affect Google’s top 1000 advertisers on mobile apps, and find that over 98% of these advertisers would always be better off sharing data, even if the data can also help their competitors bid