ResearchKit is an open-source software tool that uses iPhones to gather a range of medical-related information on users, allowing researchers access to reams of data that could inform their research. It works hand-in-hand with the iPhone’s HealthKit software, which already allows users to track their health and fitness habits.

ResearchKit essentially transforms the iPhone into a research tool, which could, in turn, revolutionize the way scientists and doctors study disease. It sets up the infrastructure needed to collect untold sums of health data.

“Numbers are everything,” Eduardo Sanchex, a doctor with the American Heart Association, said in a statement on Apple’s site. “The more people who contribute their data, the bigger the numbers, the truer the representation of a population, and the more powerful the results.”

Several institutions — including Mount Sinai, Massachusetts General Hospital and the Dana-Farber Cancer Institute — have already developed applications within ResearchKit that aim to collect information on diseases such as asthma, breast cancer, heart disease, diabetes and Parkinson’s disease. The software is open source and allows anyone to design an app for it.

The software works by using the iPhone’s accelerometor, microphone, gyroscope and GPS sensors to gather information on a user’s gait, motor impairment, fitness, speech and memory. For instance, an app called mPower uses the tapping motion on the screen to detect subtle hand tremors, a distinctive sign of Parkinson’s disease.

Users will be able to opt into the studies and control how they want their data shared with researchers, and Apple (AAPL) has built in additional privacy features that protect the identity of patients.

Essentially, ResearchKit turns everyone with an iPhone into a potential research subject, allowing institutions to gather a more diverse study population that has been otherwise inaccessible.

Medical studies have traditionally been limited by physical proximity to the major research institutions, but ResearchKit changes that. New York’s Mount Sinai, for example, won’t be restricted to the New York City metro area. It can gather information from anywhere someone with an iPhone roams.