After high school and four yrs of college, an individual desiring to continue on to become a MD (medical doctor) or a DO (Doctor of Osteopathy or Osteopathic medicine), enters med school where they become Interns. Depending on the "specialty" they choose, they could go thru 3 or 4 yrs of medical school. Some even have to go to more school, for instance those specializing to be Forensic scientists (some are called medical examiners or coroners, depending on location and state law requirements). But, that is beyond what I want to discuss in this blog.
Residents have completed their "classroom work" and have now graduated. "Are they MD'/DO's", is a question that can be answered in the affirmative. One thing that they do is go to the state board, in which ever state they are located in, and get "licensed" to practice medicine. Those records are *public* and can be searched. The first thing I do, when I get referred to *any* doc, be they resident or attending (I refer to those as "staff"), is go online and check to see 1) when they were first licensed, 2) what schools they attended, 3) If they have any "dings" on their license. Those dings could include, forgetting to re-license, malpractice of any kind, censure by the medical board, etc. Do your research on the person that you go to. That alone can save your life.
Chief Residents have been selected by the staff and may do some teaching. Their duties can vary from state to state. Check them out.
Fellows specialize in a specific training areas: pediatric neurosurgery, oncology, adult neurosurgery, for example.
Attending or Staff are are the top of the food chain. They are the "boss" of the various Residents, Chief Residents, and Fellows.
I've had the opportunity to be seen by Interns, Residents, Chief Residents, Fellows and Staff/Attending. I find it interesting to interact with them, because it also helps me understand more about myself. Be sure to do your due diligence when researching the doctor you choose to be seen by.