PROJECT SUMMARY Rheumatic diseases and musculoskeletal (MSK) disorders often persist for decades, have profound impact on quality of life, and require complex and costly management. Complexity of management is governed by the heterogeneity in risk factors for these conditions, concomitant comorbidities, and variability in responsiveness to specific treatments. This complexity requires that epidemiologic analyses use data from a range of sources, including real-world data from electronic medical records and registries. Randomized clinical trials are critical for the identification of efficacious treatments to control symptoms and/or arrest joint destruction. Observational studies and intervention trials must account for complex phenotypes and varying durations of disease; importantly, they must also address the balance between efficacy and toxicity. Outcomes of rheumatic and MSK conditions are influenced by social determinants of health, which affect access to high value care, especially for racial and ethnic minorities. Studies of the determinants of access to quality care -- including implicit bias, geographic diversity, and the role of social networks -- have the potential to improve outcomes in populations often marginalized from health care. Confronting these complex study questions and diverse data sources requires sophisticated, state-of-the-art research methods. The VERITY Methodology Core (MC) focuses on addressing these methodologic needs and analytic challenges. The VERITY MC is a centralized resource with the overarching goal of providing critical insight into the design, planning and conduct of clinical research in patients with rheumatic or MSK disorders. The focus of expertise in the VERITY MC aligns with the overall objectives of the CCCR (“VERITY”). The Specific Aims of the MC include: 1. Ensure methodological rigor in the design and implementation of studies aimed at improving outcomes in persons with rheumatic and musculoskeletal conditions; 2. Develop and advance methods to optimize design and conduct of clinical trials; and 3. Incorporate intervention approaches based on behavioral theory and behavioral economic principles and to infuse cultural perspectives and perceptions of racial and ethnic minorities into interventions. The MC has the requisite breadth of expertise to enhance the rigor of the broad spectrum of studies undertaken by the VERITY Research Community. The MC is well positioned to support one of the key VERITY objectives -- to design studies, providing the highest level of evidence, including RCTs when feasible, or trial emulation based on real world data when randomization is not feasible or ethically justified. The MC advances VERITY’s focus on patient-centeredness, particularly as it relates to social determinants of health.