sentences:  IBM and other organizations started the Patient-Centered Primary Care Collaborative in 2006 to promote the medical home model.As of 2009, its membership included "some 500 large employers, insurers, consumer groups, and doctors".In 2007, the American Academy of Family Physicians, American Academy of Pediatrics, American College of Physicians, and American Osteopathic Association—the largest primary care physician organizations in the United States—released the "Joint Principles of the Patient-Centered Medical Home".