From Apple’s ResearchKit page:

ResearchKit is an open source framework introduced by Apple that enables your iOS app to become a powerful tool for medical research. Easily create visual consent flows, real-time dynamic active tasks, and surveys using a variety of customizable modules that you can build upon and share with the community. And since ResearchKit works seamlessly with HealthKit, researchers can access even more relevant data for their studies — like daily step counts, calorie use, and heart rate.

And here’s the ResearchKit video, if you have not yet seen it.