As Health Records Go Digital, Where They End Up Might Surprise You

Two years ago, Latanya Sweeney created a graphic on the widespread sharing of medical files that shocked lawmakers, technologists and doctors.

Sweeney, who founded the Data Privacy Lab at Harvard University, produced a “health data map” that looks like a windshield cracked by a few big rocks. At the center is someone’s health record, medical provider and insurance company. Emanating from them are webs of more than two dozen organizations that could have legitimate access to the file, including transcription services, medical researchers, and even data-mining firms and pharmaceutical companies.

“Collectively, you’d hear a gasp and then a moment of silence — that was pretty universal,” she said, describing the reaction during her congressional testimony and presentations to privacy summits, academic conferences and medical schools...