<p>Ah, at least in high school everyone went by the titles of Mr/Ms/Mrs. (or if you came from my birth country, Sir/Madam) even if you were addressing principals or superintendents. </p>
<p>I realise that on several occasions I have merely called "Professor" (or Mr/Ms.) people who were deans, directors of various departments, assistant/associate deans/directors, and possibly I fear improperly addressing distinguished researchers, chairpeople and goodness knows what else. </p>
<p>But I was just trying to ask questions about course enrollment and saw only their names and emails as contacts for the course! </p>
<p>Address them by professor or Dr. even if they have other titles and positions (until they tell you to address them by first name). It's the same reason you would address your boss as "Mr Smith" rather than "Senior Director and Distinguished Manager Smith."</p>
<p>I addressed all my tenured professors as professors in all of my communications regardless of their hierarchical distinctions. I only use doctor when talking to someone who has a Ph.D but is not a teaching professor. As None put it, it would be really weird if you actually addressed them by their full titles. You only do that when you introduce them in a formal lecture of panel discussion.</p>
<p>Dean is kinda like President, I suppose. I'd always refer to my professors as Professor XYZ, and most other people Doctor. Generally I found that non-professors at academic institutions prefer to drop the Doctor in front of their name and prefer to just go by their first or last name.</p>
<p>And grad students should go by their first name (or possibly Mr. Lastname) since, if they're a grad student, they're not a doctor yet. :p</p>
<p>You can't go wrong calling someone "professor" who has an academic appointment. Department chair, Dean, even the president of the university all usually have academic tenureship as a professor. </p>
<p>The only thing to watch for is administrative deans and the like, who don't usually have academic appointments and many times don't teach, have doctorates, or do research as well. These don't usually go by professor or dr (the latter unless they actually do have a doctorate or other degree anyway)</p>
<p>Most of my professors are pretty straight forward. When I call them by Dr. ( insert last name) or Professor ( insert last name ), which is rare, they often say, "oh call just call me Gary", or whatever their first names are. In general, if they don't give preference before hand, call them by professor ( last name ) because there are some part time professors that don't have Ph.Ds</p>
<p>Well when I look them up later on the directory I discover too late what their full ranges of appointments are. Also is it a big faux pas to give 'commoner' titles like Mr. / Ms. etc?</p>
<p>If you don't know anything about a person, called them "Professor Lastname." If you know that they have a doctorate, you could call them "Doctor Lastname." If they're a dean, I would call them "Dean Lastname." For administrative personnel I usually go with Mr., Mrs., or Ms. unless you know something more.</p>
<p>If they are teaching a class, you should at least call them professor X. If they just work at the place, call them Mr/Mrs X. If they are a dean, they should be called Dean X.</p>
<p>I don't think I've ever called anyone "professor", it's a bit harry potter for me. If it's a grad student or instructor, it's Ms/Mrs/Mr. X, unless they say you can call them by their first name (My world lit instructor was Ms. Bolden). For actual professors, which in the vast majority of the time have Ph.D's anyway, I call them Dr. X (My anthropology professor is Dr. Shuler) unless they say otherwise, again.</p>