Credentialing committees within hospitals review the professional backgrounds and educational training of physicians prior to granting them permission to admit and treat patients. A grant of staff privileges also states the specific treatments and procedures that the specialist will be allowed to provide and perform. Additionally, hospitals require proof of professional liability insurance, details regarding prior professional liability claims, and information concerning any underwriting action taken against a physician (e.g., cancellation of coverage) before a hospital agrees to grant staff privileges. The refusal to grant staff privileges by credentialing committees is a frequent source of claims brought against both the hospitals and the individual physicians who serve on such committees by physicians who have been refused admitting privileges. As a result, both physicians professional liability policies and hospital professional liability policy forms explicitly cover what are known as "credentialing claims."