Embedded assessment is a technology design strategy to drive preventive health care and early disease detection. This approach addresses barriers to early detection observed through ethnographic research. Health monitoring is integrated into everyday devices and then translated into personalized feedback that supports immediate wellness and long-term disease prevention. Three embedded assessment projects are described that involve close collaboration between the author (a clinical psychologist) and engineers in Intel's Digital Health Group. First is a mobile oximetry and feedback tool designed to facilitate safe exercise and thereby prevent escalation of heart failure. Second is a system of sensors and ambient displays to support social interaction and prevent cognitive impairment among older adults. Third is a mobile coaching system, responsive to physiological sensors, for people whose emotional reactivity poses risk for coronary artery disease. In these projects and ongoing work, granular biological and behavioral metrics are translated into psychologically meaningful feedback in order to motivate change.