Data Brokers Sell Health Inferences from Phone Location Data

Data brokers combine smartphone location records with other personal information to infer health problems and sell those inferences to businesses promoting unproven treatments. San Diego resident Chris McQueen completed leukemia treatment a year and a half ago but continues to receive advertisements for purported cures. Advertisements appearing during McQueen's oncologist appointments and monthly blood tests promoted juice cleanses, natural treatments and Mexico clinics promising recovery with little chemotherapy. McQueen fears patients could risk death by choosing untested treatments over oncologists' recommendations.

A 2022 American Medical Association survey found that more than 92% of patients opposed making their health information available for purchase. The Health Insurance Portability and Accountability Act does not protect phone location records generated at hospitals, abortion clinics or Alcoholics Anonymous meetings. Privacy and legal experts argue that enforcement against individual companies cannot stop the industry and want more states or Congress to ban advertisers' phone location tracking. Privacy advocates note that individual settlements establish no requirements for other companies because settlements are neither legislation nor regulations.

California Gov. Gavin Newsom vetoed legislation on September 27 that would have prohibited selling and sharing location records and other sensitive personal information, calling the measure excessive. A recent Stanford University study found that only 9% of data brokers comply with California's existing law allowing consumers to delete or correct data and discover which personal records businesses sell. Consumer Reports published model legislation in January to help states prohibit or restrict sales of geolocation data, which uses GPS to follow movements in real time. Virginia, Oregon, New Jersey, Maryland, Delaware and Connecticut already prohibit sales of precise geolocation data. Digital advertisers have lobbied state governments against proposed restrictions.

The Federal Trade Commission warned retailers in August about raising prices using private consumer information. A May settlement bars Idaho-based Kochava and a subsidiary from disclosing, sharing or selling sensitive location information without consent, following FTC allegations that the companies sold records from hundreds of millions of mobile devices capable of revealing visits to hospitals, churches, abortion clinics and other sensitive places. Kochava did not answer requests for comment.

Electronic Frontier Foundation senior staff attorney F. Mario Trujillo said brokers and advertisers dispute the sensitivity of location information, but argued that comprehensive location histories reveal sensitive details. Advertising trade groups argue that targeted advertisements save consumers time, reduce product-search costs and fund websites and apps without subscriptions or paywalls. Jim Potter, executive director of 4As Health, said national privacy legislation should prevent harmful or unexpected data uses without obstructing services consumers request and expect.

A 2024 report by Federal Reserve Bank of St. Louis economists found that Alphabet, Meta and Microsoft had profit margins at least twice the services-sector average. Other studies found that established data-collection systems let brokers repeatedly sell the same records, including to AI companies, at minimal additional cost. A 2019 study found that brokers held information associated with more than 90% of Facebook accounts in the United States. A 2020 Electronic Frontier Foundation report said Google supplied potentially hundreds of digital advertising companies with sensitive information, including geolocation, device identifiers, identifying cookies and browsing histories. Google and Meta did not answer requests for comment. Microsoft supports national privacy legislation similar to the European Union's law, and spokesperson Paige Fisher said using modern technology should not require surrendering privacy.

Privacy Rights Clearinghouse and the Electronic Frontier Foundation identified 750 data brokers operating in the United States as of last year. The organizations said many brokers lacked state registration and might not provide simple opt-outs or ways to verify records comparable to credit reports. Consumer Reports said in September that volunteers found frequent errors in company files, including one file assigning a person four ages, both male and female classifications, three substantially different incomes and occupations the person had never held. Consumer Reports policy analyst Matt Schwartz said brokers use device location histories to create marketing categories that could identify reproductive-health visits, protest participation or political-party support through rally attendance. Schwartz warned that hundreds of brokers collecting information in an unregulated market create substantial exposure to data breaches.

Schwartz said requests for consumers to opt in often authorize unrestricted use, sharing and sales of location and health information. Schwartz said consumers can face a choice between providing sensitive information and losing access to a website or app. An August Electronic Frontier Foundation policy paper said removing sensitive destinations from profiles still lets brokers and advertisers infer visits by following routes immediately before arrival and after departure.

Trujillo recommends restricting apps' location access and disabling advertising tracking, while users can also switch off location services or activate airplane mode before visiting sensitive places. Atlanta neurologist Julien Cavanagh said unexplained neurological symptoms now prompt questions about whether patients take supplements purchased online. Cavanagh said fraudulent treatments can cause toxicity, vitamin or micronutrient deficiencies, or interference with prescribed medicines.

At least 20 states let residents demand deletion of personal information, although consumers generally must approach each broker separately. California provides a centralized portal for deletion requests. iPhone users can disable all location access or individual apps' access through Location Services in Settings, and disable tracking requests through Privacy & Security, Tracking and Allow Apps to Request to Track. Android users can disable location access globally or by app through Location settings, and remove the advertising identifier through the security and privacy settings, privacy controls, Ads and Delete advertising ID.