Health data is particularly vulnerable, the researcher says. Search terms for disease symptoms, online purchases of medical supplies, and even the RFID tags on drug packaging can provide websites and retailers with information about a person’s health. As Crawford and Jason Schultz, a professor at New York University Law School, wrote in their paper: “When these data sets are cross-referenced with traditional health information, as big data is designed to do, it is possible to generate a detailed picture about a person’s health, including information a person may never have disclosed to a health provider.” And a recent Cambridge University study, which Crawford alluded to during her talk, found that “highly sensitive personal attributes”— including sexual orientation, personality traits, use of addictive substances, and even parental separation—are highly predictable by analyzing what people click on to indicate they “like” on Facebook. The study analyzed the “likes” of 58,000 Facebook users. Similarly, purchasing histories, tweets, and demographic, location, and other information gathered about individual Web users, when combined with data from other sources, can result in new kinds of profiles that an employer or landlord might use to deny someone a job or an apartment.
