Project Summary/Abstract The overall aim of this Columbia University Science of Behavior Change (SOBC) Resource and Coordinating Center (RCC) administrative supplement proposal is to increase the scientific rigor of mechanisms-focused behavioral science by developing a transparent, rigorous, and reproducible approach to ontology development for constructs in behavioral medicine. To our knowledge, this will be the first time that experts in stress, its measurement, and its role as a construct in the broader field of the behavioral sciences are convened to work with experts in information science, natural language processing, and automated learning to develop a domain ontology of stress for use by the field as a whole. The aims of this supplement are aligned with the goals of the RCC, which include (1) serving as a hub for scientists to evaluate, discuss, and disseminate mechanisms- focused behavioral science; (2) engaging with national scientific organizations and bringing basic and applied/clinical scientists together to promote collaborations and further advances in mechanistic behavioral science; and (3) conducting outreach and dissemination of the experimental medicine approach. Specific aims of the supplement are to: (1) Convene stakeholders and experts in the stress construct, stress measurement, and ontology development tools to choose the scope, approaches, materials, and specific tasks necessary to develop an ontology of stress that is maximally useful to the field of behavioral science. Deliverables: A published record of our stakeholder selection and organizational processes, goals for the collaboration, and a priori plan for engineering an ontology of stress. (2)Develop a rigorous ontology of one or more components of stress. Deliverables: A rigorous, intuitive, and useful ontology of stress that can facilitate automated reasoning and organize existing literature on stress-related constructs. The Stress Ontology is enabled by the ITEM (Indicator Terminology for Explanation and Measurement) Ontology, the Larsen team’s recently completed domain ontology. ITEM is the first ontology for modeling the sub-indicator entities in psychological measures, a necessary first step for accurate measure and construct integration. (3) Conduct outreach and dissemination of the ontology development process. Deliverable: Published and web-based materials for teaching the value of ontologies in behavioral science, describing the expertise, tools, and steps necessary for constructing ontologies, and demonstrating the utility of our stress ontology specifically. (4)Integrate finalized ontologies into SOBC efforts. Deliverables: We will include ontology development and related insights into SOBC/the experimental medicine approach dissemination efforts, including the SOBC website.