Chart in the United States.
The web page is describing the official residencies and their associated fellowships.
The left column shows residencies. Residencies are universally completed, starting after medical school finishes, and can last from 3-7 years usually. They specialize you to a particular field. But be careful as certain specialties are very broad such as internal medicine, while others are already significantly narrow such as neurosurgery. Specialties that are already narrow are ones that most people would not further train in. This makes sense as fellowships are for "subspecializing" and subspecializing in an already narrow specialty does not make as much sense as subspecializing in a quite broad specialty such as internal medicine.
After completing a residency, a person can complete a fellowship within that field (the right column). This means you are "sub-specializing." These also last a variable amount of time, usually 1-3 years.
Some common questions
"When does it become appropriate to refer to a person in medical training as a "doctor?"
- Once medical school is finished, the degree is granted. Thus, it is appropriate after graduation from medical school.
"I have heard the term "general practitioner (GP)." To whom does that refer to?"
- A very long time ago, it was typical for a medical student to graduate medical school and perform an "internship" that lasts one year. The person would not undergo any more training, and their scope of practice would be very broad. This individual would have been called a GP.
- Residencies became common, and later universal, and these allowed doctors to spend a few more years training and narrowing their scope of practice to a specific specialty. These specialties include family medicine and internal medicine. You might think the latter two are quite broad fields, of which they are. The reason they are called "specialties" is they are still more specialized than general practitioners.
- The first year of residencies is informally called "internship," or the "intern year." This year borrows from the internship year GPs used to complete in, but it is still more broad. Usually, this first year is medical or surgical in nature and therefore is still more narrow than the internship GPs would have completed.
"When can a doctor practice independently?"
- Technically, once the physician becomes licensed, he or she can practice independently. This license is obtained sometime during residency. This creates a complicated status when a resident has not completed residency yet has obtained a license. What happens in that situation is the resident has to be supervised within the scope of the residency, but can practice ("moonlight") independently at a separate location, if the residency program allows.
"Do different specialties have different licenses?"
- No. In medicine, the license is unrestricted. This means the doctor can practice as he or she wishes. The limitation is that he or she should only practice in a field he or she is competent it. Please note the word "should." This is usually the area the person completed residency, and possibly, a fellowship in.