Sharing is caring, but not error free: transparency of granular controls for sharing personal health information in social networks.

When patients share personal health information with family and friends, their social networks become better equipped to help them through serious health situations. Thus, patients need tools that enable granular control over what personal health information is shared and with whom within social networks. Yet, we know little about how well such tools support patients' complex sharing needs. We report on a lab study in which we examined the transparency of sharing interfaces that display an overview and details of information sharing with network connections in an internet-based personal health information management tool called HealthWeaver. Although participants found the interfaces easy to use and were highly confident in their interpretation of the sharing controls, several participants made errors in determining what information was shared with whom. Our findings point to the critical importance of future work that examines design of usable interfaces that offer transparent granularity in support of patients' complex information sharing practices.