DATA SHARING ACROSS DECENTRALIZED CLINICAL TRAILS USING CUSTOMIZED DATA ACCESS POLICIES

Methods, systems, and apparatus, including computer-readable media, for a hierarchical multi-tenant data access platforms. In some implementations, the a server system stores data collected through a multi-tenant data access platform configured to collect data for each of multiple tenant organizations and to selectively make the collected data available according to policies associated with the respective tenant organizations. The server system receives a request associated with a user, and the server system generates and provides a response according to the organization hierarchy data and policy data for the unit of the organization that has data that would be used in generating the response to the request.