Project Summary/Abstract This study will develop, assess usability of, and refine a a ?diagnosis-driven? computer decision support system (CDS) and a longitudinal alert system to improve safe and patient-specific prescribing of direct oral anticoagulant (DOAC) medications. We will develop diagnosis-driven CDS tools for the two most common conditions leading to DOAC use (atrial fibrillation and venous thromboembolism). Each will guide the clinician through drug and dose selection based on critical patient characteristics, laboratory values, and concurrent medication use. User-center design principles will underly an iterative approach of heuristic evaluation, usability testing, and semi-structured interviews with 15 practicing clinicians. We will also develop a serial, longitudinal system to continually re-assess DOAC prescribing appropriateness and alert clinicians when issues develop. Following the ?5 Rights? model endorsed by AHRQ, we will assess for the most acceptable format, channel, and time in clinician work flor for these alert notifications to occur. Findings from this study will lead to improvements in safe management and a reduction in adverse drug events for the three million patients prescribed DOACs nationwide.