This Clinical Observational (CO) Studies in Musculoskeletal, Rheumatic, and Skin Diseases (R01 Clinical Trial Not Allowed) PAR, was re-issued as a result of the Simplifying Review of Research Project Grant Applications [link: https://grants.nih.gov/policy-and-compliance/policy-topics/peer-review/simplifying-review]. The Simplified Review changes in Section V are the only changes that have been made. All other aspects of this funding opportunity remain the same.