After graduation, medical practitioners often undertake further training in a particular field, to become a medical specialist. In North America, this is often referred to as residency training; in Commonwealth countries, such trainees are often called registrars.
In the large English-speaking federations (United States, here Canada, Australia), the licensing or registration of medical practitioners is done at a state or provincial level. Australian states usually have a "Medical Board," while Canadian provinces occasionally have a "College of Physicians and Surgeons." All American states have an agency which is ordinarily called the "Medical Board", although there are alternate names such as "Board of Medicine," "Board of Medical Examiners", "Board of Medical Licensure", "Board of Healing Arts" or some other variation. After graduating from medical school, physicians who wish to practice in the U.S. sometimes take standardized exams, such as the USMLE for MDs, COMLEX-USA for osteopathic physicians, the NBDE exams for dentists, the NBPME exams for podiatrists, or the NPLEX for naturopaths which enable them to obtain a certificate to practice from the appropriate state agency.