Smartphones are loaded with sensors—accelerometers, gyroscopes, touch screens, microphones, and GPS—which could give doctors a much more detailed snapshot of their patients’ progress. This week, Apple announced a new software platform to tap into that data: ResearchKit.

Apps on the new platform allow iPhone users to enroll in clinical trials on heart health, Parkinson’s, or asthma, and thousands have already signed up. But critics say the smartphone-driven studies have flaws: They’ll only sample a narrow slice of humanity—wealthy, educated iPhone users—and they could generate misleading data.

Arielle Duhaime-Ross, who reported on the announcement for The Verge, and John Wilbanks, who worked on several of the apps, join us to discuss.