Auditing Offline Data Brokers via Facebook's Advertising Platform

Data brokers such as Acxiom and Experian are in the business of collecting and selling data on people; the data they sell is commonly used to feed marketing as well as political campaigns. Despite the ongoing privacy debate, there is still very limited visibility into data collection by data brokers. Recently, however, online advertising services such as Facebook have begun to partner with data brokers-to add additional targeting features to their platform- providing avenues to gain insight into data broker information. In this paper, we leverage the Facebook advertising system-and their partnership with six data brokers across seven countries-in order to gain insight into the extent and accuracy of data collection by data brokers today. We find that a surprisingly large percentage of Facebook accounts (e.g., above 90% in the U.S.) are successfully linked to data broker information. Moreover, by running controlled ads to 183 crowdsourced U.S.-based volunteers, we find that at least 40% of data broker sourced user attributes are not at all accurate, that users can have widely varying fractions of inaccurate attributes, and that even important information such as financial information can have a high degree of inaccuracy. Overall, this paper provides the first fine-grained look into the extent and accuracy of data collection by offline data brokers, helping to inform the ongoing privacy debate.

Acxiom和Experian等数据经纪人从事收集和销售人数据的业务；他们出售的数据通常用于喂养营销和政治活动。尽管存在持续的隐私辩论，但数据经纪人对数据收集的可见性仍然非常有限。但是，最近，在线广告服务（例如Facebook）已开始与数据经纪人合作，为其平台添加其他定位功能，从而提供了途径，以深入了解数据经纪人信息。在本文中，我们利用Facebook广告系统以及与七个国家 /地区的六个数据经纪人的合作伙伴关系，以深入了解当今数据经纪人数据收集数据的程度和准确性。我们发现，很大一部分的Facebook帐户（例如，在美国90％以上）已成功链接到数据经纪信息。此外，通过运行对183位总部位于美国众包的志愿者的受控广告，我们发现至少有40％的数据经纪人的用户属性完全不准确，用户可能会在不准确的属性中存在很大变化的分数，甚至包括财务信息等重要信息也可能具有高度的不准确性。总体而言，本文通过离线数据经纪人提供了第一个细粒度的研究，以了解数据收集的程度和准确性，从而有助于告知持续的隐私辩论。