I am a first-time lecturer for an American university (am a PhD student), and am giving midterm and final exams in the course, which comprises an introduction to engineering and how to work with systems in a methodological way.
I am designing the midterm exam for the course, and the students have an allotted 50 minutes to complete it. Most of the questions are brief short-answer questions (around 2-3 sentences for an answer is sufficient), followed by some multiple choice and fill-in-the-blank questions.
I took the midterm by myself and timed the length of completion, which was around 12 minutes for me. From other professors that I have taken classes from, this seems to be the standard (i.e., if the professor can complete the exam in 1/4 of the allotted time, then it is an appropriate length).
Does this seem reasonable? I'd like to hear some related experiences from other instructors.