METHODOLOGY CORE ABSTRACT The Methodology Core is central to our CCCR's goal of acting as a hub and resource for conducting and disseminating high quality clinical research in rheumatic and musculoskeletal diseases (RMD). This Core brings together investigators from diverse scientific backgrounds whose clinical research expertise will serve the broader RMD research community in the following ways: 1) Provide support in advanced epidemiologic methods, statistical approaches, and machine learning approaches; 2) Utilize and make available our CCCR's cohort studies and large administrative claims and electronic health records databases; 3) Advise on outcome measures and provide training in specialized study protocols (e.g., quantitative sensory testing, imaging, wearable sensors); 4) Provide input regarding conditions for which we have unique expertise, including osteoarthritis, crystal-related arthritis, spondyloarthritis, and musculoskeletal pain mechanisms, though the methods expertise and resources allow for broad application to the study of other RMDs. In this renewal, we will expand our use of, and guidance related to, advanced causal inference, machine learning and deep learning, and digital health applications (including wearable sensors). A new area we will add in the renewal is implementation science to enhance our capabilities to narrow the knowledge-practice gap and health inequities in key RMDs. A key feature of this Core is a weekly clinical research meeting, known as the Research Accelerator, in which a diverse group of researchers provide interdisciplinary input into all facets of clinical research projects. By having rheumatology, rehabilitation, epidemiology, biostatistics, and other specialized investigators meet once a week together, the Methodology Core creates interdisciplinary conversations and makes available methodologic expertise to clinician researchers that would otherwise not be part of their grants or scientific projects. Our Boston University CCCR group is well known for training early-stage investigators, many of whom are prominent clinical researchers in RMD research domestically and globally. The Methodology Core will continue to emphasize training. In this renewal, we will expand our educational programming, including a new Visiting Professor program, an expanded monthly journal club with virtual attendance options for the broader research community, an Advanced Methodology Seminar to act as a continuing education opportunity for our analysts and methodologists, and will leverage social media to provide summary “threads” from our various educational sessions and to showcase our CCCR work. Through these endeavors, the Core will expand and enrich the scope of research questions addressed and methods used to address them, ultimately benefiting the health and quality of life of individuals living with RMDs.