Senior social workers must be licensed or certified by a state at the advanced practice level which included an advanced generalist or clinical examination, unless they are grandfathered by the state in which they are licensed to practice at the advanced practice level (except for licenses issued in California, which administers its own clinical examination for advanced practice) and they must be able to provide supervision for licensure. Senior social workers typically practice in a major program area such as but not limited to: Polytrauma Rehabilitation Center or Polytrauma Network Site; a Spinal Cord Injury Rehabilitation Center, or a national VHA referral center, such as a national Center for Post-Traumatic Stress Disorder or a national Transplant Center, or other program areas of equivalent scope and complexity.