The ARDS, Pneumonia, and Sepsis (APS) Coordinating Center will support a highly functional and integrated clinical and translational research infrastructure that will enhance the quality and scientific rigor of the research conducted by the APS Phenotyping Consortium. We are a team composed of leading content and methods experts at Vanderbilt, Johns Hopkins, and University of California San Francisco. We will provide Coordination for ARDS, Pneumonia, and Sepsis supporting Training, Organization and Network Efficiency: ‘CAPSTONE’. We will support the clinical centers (CCs) in enrolling and sustaining a diverse cohort; enable the efficient and standardized capture of multi-modal cohort data with repeated measurements; model the data to understand mechanistic underpinnings of APS, including the interplay of underlying and static risk factors; and segment the population into similar prognostic and predictive phenotypes. This will enable scientific progress towards a deeper mechanistic understanding of critical illness syndromes and recovery. Functionally, we will 1) Implement the study design, data capture, and statistical analysis unit. Coordinate protocol development; establish a REDCap-based data collection, management, and security framework; conduct and support analyses; generate reports; make curated data widely available for research through a facilitated storefront; 2) Implement the clinical research management unit. Maintain cohort integrity and adherence to the protocol and manual of operations, perform routine monitoring of data quality and site performance; training of study staff; image and biospecimen management. Support site communications; facilitate recruitment and retention; and 3) Implement the stakeholder engagement and development unit. Establish bidirectional, longitudinal engagement from diverse communities; help CCs build and sustain trust; ensure strengths of each CC are nurtured and shared; facilitate dissemination of findings; support skills and career development among research teams. Our efforts will expand foundational work on APS phenotyping, identify gaps, and help create methods for redefining critical illness syndromes with the ultimate goal of improving and personalizing management strategies that will curtail the devastating morbidity and mortality caused by APS.