Launched in 2002 and completed in 2015, the Osteoarthritis Initiative (OAI) represents a collaboration of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Institute on Aging (NIA) and the private sector, working together to improve the efficiency of drug development and clinical trials for the treatment of OA. The study created a public access research resource that enables the worldwide scientific community to examine and to analyze knee radiographs, X-rays and MRIs and a variety of other clinical data to better predict the progression of OA and develop new treatments to slow progression of or modify this disabling disease, which affects more than 15 million people in the United States. Among the many research efforts made possible by this resource is the FNIH Biomarkers Consortium Osteoarthritis Biomarkers Project.