Project Summary (Abstract) This four-year Center grant proposal has as its long-range goal the active development and dissemination of approaches to achieve Diagnostic Excellence in the emergency department (ED) by leveraging safety science principles and strategies. The proposal seeks to mature and focus ED diagnostic safety, quality, equity, and value-oriented activities at an existing Center at Johns Hopkins Medicine (JHM). The Armstrong Institute Center for Diagnostic Excellence (DXC) will become part of a new AHRQ-sponsored network of Diagnostic Centers of Excellence (DCE) via RFA-HS-22-008, to which this application responds. Diagnostic errors are the largest cause of preventable harms in US medical care, likely affecting more than 12 million Americans each year and leading to permanent disability or death for at least 0.5 million. The ED is a known high-risk site for diagnostic errors where patients are at risk for misdiagnosis-related harms. To achieve the goal of Diagnostic Excellence, it will be necessary not only to develop strategies that improve diagnostic accuracy and reliability, but also to identify and overcome barriers to their effective use and dissemination. Safety science applies engineering and social science expertise to address hazards in the health care field. Currently, Safety I (e.g., “find and fix”) and Safety II (e.g., “resilience engineering”; “high reliability organizing”) are active and ever-evolving approaches to quality improvement. Safety I strategies emphasize informing harm prevention by identifying failed processes and adverse events, while Safety II strategies take complexity and human factors as critical to understanding the effects of socio-technical systems of care on patient safety and quality. Often improvement teams adopt one or the other strategy, but, in this proposal, we will blend the two approaches, capitalizing on the strengths of each through the process of double-loop learning. “Double-loop” learning originates from organizational science and emphasizes “meta” learning through deliberate examination of how structural and psychological norms interact with the normal operational “single-loop” mechanisms of feedback and learning. As a result, double-loop learning represents a unique mechanism to integrate Safety I and II strategies and thereby advance safety science in pursuit of Diagnostic Excellence. Projects supported by this proposal will pursue ED Diagnostic Excellence through a mix of research and quality improvement activities both within and beyond the walls of JHM. Our transdisciplinary research team will pursue Diagnostic Excellence via three Specific Aims: (1) target the top causes of ED serious misdiagnosis- related harms; (2) partner and share knowledge with the DCE network and others; and (3) develop a JHM framework for sustainability of the DXC’s mission. Each Aim will be accompanied by double-loop “meta” learning that informs our understanding of barriers and facilitators to Diagno...