The privacy choices that individuals make regarding their own devices often affect the privacy of those around them. At the same time, those privacy choices are constrained by the choices of the people who manufacture the devices. These issues are becoming more urgent with the expansion of the Internet of Things (IoT) into applications from smart-home devices to public surveillance. The massive amounts of data collected and shared by IoT devices are raising profound privacy concerns not only among primary users of IoT (those who purchase and install the devices), but also secondary users (e.g. other members of their households), and bystanders (e.g. visitors to or employees in a smart home, or people passing by a self-driving car). A key goal of this project is to understand the varying roles these parties have in decisions about data collection, and what products could be doing to better meet their privacy expectations. To that end, the second key goal is to work with designers and developers of IoT devices to develop materials, methods, and models for building products that enhance daily life without endangering social fabrics or norms. Together, these understandings and methods will expand the impact of the work widely in educational and product development contexts, and provide useful input to technology policymakers.<br/><br/>The project approaches this research from multiple angles. First, using surveys and other empirical methods, the research team will explore the IoT experiences, privacy expectations, and concerns of groups of people for whom bystander concerns are likely to be amplified, such as domestic employees (e.g. in-home care attendants), or residents and guests of pre-equipped "smart" housing. Second, via interviews and surveys, the research team will study smart home product teams to understand the perspectives of the people who design and build IoT products, including how they currently make decisions about the data use of non-primary users -- if they consider it at all. Based on the findings, the researchers will develop a) prototype interventions to provide non-primary users with relevant information and/or better control over their privacy, and b) interventions to improve product teams' decision-making about bystander privacy in the design process. The research team will evaluate the interventions via in-home/in-office experiments and cognitive walkthrough usability studies.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.