TNG itself is a little unclear on this point, as Troi had to take a test to become qualified as a bridge officer, but during "Disaster" is deferred to by the far more qualified (in military terms) Ro and O'Brien ... so it's a little unclear what she gains when she passes the test in "Thine Own Self," besides the rank of commander.
It's interesting that in M*A*S*H, a fictionalized and extremely un
-military medical corps, even the most un-military character are usually referred to as Captains Pierce and McIntyre (or Captains Pierce and Hunnicutt, depending on the season).
"I don't mind the fact that race, creed, sex, ethnicity, and the disabled are protected classes, but I draw the line at stupidity." -- Jethro Elvis
: Attack otters of the ass. In submarines.