PROJECT SUMMARY Background. High blood pressure is common in adults, and – despite the fact it can be controlled – 40% of those with high blood pressure do not have it controlled and remain at high risk for heart attack, strokes, and kidney failure. Controlling high blood pressure can be achieved through medications and changes in behavior and lifestyle, including losing weight, changing diets, increasing activity, reducing alcohol intake, and stopping tobacco use. These require self-management and monitoring of blood pressure; new tools such as web applications can help provide this support, but need standardized approaches to reflect recommendations for blood pressure control and to better engage those with high blood pressure. Our innovation will combine social cognitive theory and behavioral economics with a standards based CDS tool to improve blood pressure control. Goal. The goal of the proposal is to implement sharable, interoperable, and scalable patient-facing clinical decision support for high blood pressure. Our objectives are to refine and implement a patient-facing, adaptable Collaboration Oriented Approach to Controlling High blood pressure (COACH CDS system in 3 diverse settings, using implementation science and patient engagement to maximize effectiveness. Then, we will perform a mixed methods study including a randomized controlled trial using implementation science and social cognitive theory to test effectiveness of the application at lowering blood pressure; and finally to develop robust, sharable, interoperable mechanisms to aid in further dissemination and implementations of patient- facing CDS. Our methods will be to implement existing, interoperable CDS into 3 different sites and then perform a randomized controlled trial with qualitative and quantitative components to understand effectiveness and implementation issues. We will collaborate with a broad number of groups – including patients – to further disseminate our work.