Ida Sim, MD, Ph.D. is a primary-care physician, informatics researcher, and entrepreneur. She is a Professor of Medicine at the University of California, San Francisco, where she co-directs Informatics and Research Innovation at UCSF’s Clinical and Translational Sciences Institute, and is Director of Digital Health for the Division of General Internal Medicine. Dr. Sim is a global leader in the technology and policy of large-scale health-data sharing. She is a co-founder of Open mHealth, a non-profit organization that is breaking down barriers to mobile health app and data integration through an open software architecture. She co-developed CommonHealth, an open-source software suite bringing to the Android ecosystem the equivalent of Apple Health’s ability to access and share EHR data. Dr. Sim is also co-founder of Vivli, the world’s largest data-sharing platform for participant-level clinical trial data. In 2005, she was the founding Project Coordinator of the World Health Organization’s International Clinical Trials Registry Platform, where she led the establishment of the first global policy on clinical trial registration.