The Methodology Core of the proposed UCSF Multidisciplinary Clinical Research Center (MCRC) will serve as the hub for all MCRC projects and activities and allow the Center to pursue its program of research on health disparities in the rheumatic diseases. The primary goal of the Methodology Core is to advance clinical research at UCSF in outcomes of rheumatic conditions, building upon the existing structure developed during the current MCRC and expanded through additional extramural funding. A key component of the MCRC is the provision of shared data sources, allowing for cross-disciplinary collaborations and productive research programs of MCRC faculty and trainees. The specific aims of the Methodology Core are to: provide methodological and biostatistical support and oversight to MCRC projects and non-MCRC projects that use MCRC data sources; handle all data collection, including training and supervision of data collection staff; manage and distribute the data; provide guidance in appropriate analysis strategies for Core Unit data; and provide mentorship to trainees and junior faculty in developing and completing research projects. The shared primary data sources within the Methodology Core Unit are the Lupus Outcomes Study and the Rheumatoid Arthritis Outcomes Study. Both studies are longitudinal, incorporating such varied modalities of data collection as survey interviews, medical chart reviews, laboratory assays, in-person assessments, and genotyping. The cohorts are diverse in terms of race/ethnicity, socioeconomic status, and primary language The capacity to administer surveys in Spanish expands the MCRCs ability to understand the causes of disparities in onset, progression, health care, and outcomes of systemic lupus erythematosus and rheumatoid arthritis. The Methodology Core will fulfill its training mission through a broad range of activities, including individual mentorship, regular seminars in applied methods, and conferences devoted to clinical research in rheumatology. The Methodology Core leadership has a successful track record of fostering high quality research and attracting and advancing talented junior investigators. The educational component of the proposed Methodology Core will continue to support rigorous research methods in our trainees and foster collaborations across disciplines among investigators seeking to advance clinical research in rheumatology.