Automated Experiments on Ad Privacy Settings: A Tale of Opacity, Choice, and Discrimination

TitleAutomated Experiments on Ad Privacy Settings: A Tale of Opacity, Choice, and Discrimination
Publication TypeConference Paper
Year of Publication2015
AuthorsDatta, A., Tschantz M. Carl, & Datta A.
Published inProceedings on Privacy Enhancing Technologies
Date Published04/2015
Other Numbers3803
Keywordsbehavioral advertising, blackbox analysis, choice discrimination, information flow, transparency

To partly address people’s concerns over web tracking, Google has created the Ad Settings webpage to provide information about and some choice over the profiles Google creates on users. We present AdFisher, an automated tool that explores how user behaviors, Google’s ads, and Ad Settings interact. AdFisher can run browser-based experiments and analyze data using machine learning and significance tests. Our tool uses a rigorous experimental design and statistical analysis to ensure the statistical soundness of our results. We use AdFisher to find that the Ad Settings was opaque about some features of a user’s profile, that it does provide some choice on ads, and that these choices can lead to seemingly discriminatory ads. In particular, we found that visiting webpages associated with substance abuse changed the ads shown but not the settings page. We also found that setting the gender to female resulted in getting fewer instances of an ad related to high paying jobs than setting it to male. We cannot determine who caused these findings due to our limited visibility into the ad ecosystem, which includes Google, advertisers, websites, and users. Nevertheless, these results can form the starting point for deeper investigations by either the companies themselves or by regulatory bodies.


This work was partially supported by funding provided through National Science Foundation grant CCF: 0424422 (“Team for Research in Ubiquitous Secure Technology (TRUST)”) and CNS: 1064688 ("Semantics and Enforcement of Privacy Policies: Information Use and Purpose"). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors or originators and do not necessarily reflect the views of the National Science Foundation.

Bibliographic Notes

Proceedings of the Privacy Enhancing Technologies Symposium (PETS 2015), Philadelphia, Pennsylvania, pp. 92-112

Abbreviated Authors

Amit Datta, M. C. Tschantz, and Anupam Datta

ICSI Research Group

Networking and Security

ICSI Publication Type

Article in conference proceedings