Oral exams can have various pedagogical benefits in certain
First, I would make this statement stronger: for many reasons, I consider oral exams an invaluable tool in teaching, and I require them whenever the size of the class is compatible with the time constraints set by the university exam schedule.
but can also make some students feel anxious.
True, but I also think that this anxiety, if sufficiently controlled, can also have a positive effect on the student.
Here, I probably cannot add too much to the several excellent answers already given, but I would like to stress that one can, and possibly should, adapt the different strategies to the exam type and duration. I'll give a couple of examples from my experience. To better understand the context, a few country-specific remarks (I teach in Italy):
- Exams are public, and anyone can attend and listen to the exams. Even in case of scheduled oral exams, many students want to listen to their friends, classmates or simply listen to what kind of questions come up.
- We don't have university guidelines on how to run oral exams, and every professor has its own way: type, duration and evaluation can vary.
- As a student I took most of my oral exams at the blackboard, but nowadays we mostly sit at the desk with the student: it's definitely less stressful for them.
- I'm currently teaching in English to international students and the oral exam is in English, which is a second language for virtually all the students (and me, indeed), and this certainly adds stress.
Depending on the course, I can either divide the exam in a written part and an oral part or just have the oral exam (as I said, I rarely require written-only exams):
- In case of a two-part exam, the oral part has a duration of 20 to 40 minutes, with 2-3 questions, depending on the relative significance of the two parts. The oral exam usually follows the written part by a few days (the time needed to grade the written part), and the students can take the oral part only if the written part reaches a minimum threshold. The results of the two parts can be combined in various way, e.g., weighted average or increment/decrement. Passing the written part is by no means guarantee of passing the exam: the student can be failed at the oral part.
- In the case of an oral-only exam, the duration is usually 1 hour.
For a two-part exam, I usually start the exam in a soft way by discussing with the student the results of the written part: the student can read my comments, ask questions on the solution and can clarify its doubts. I can also use the written part as a starting point for the first question. In my experience, this is a good way to relieve a bit the stress.
For oral-only exams, whenever the course allows, I try to divide the oral exam in two times. In the first half, I ask the students to discuss a paper that they had to choose during the course; they can come with notes and use them during the discussion. It seems to me that students like this type of discussion -- as much as they can like an exam, of course -- and this helps to warm them up for the second half, which is more canonical and specific on the course content.
After warm-up, the exam continues with broad questions. Admittely, here, I don't follow Wrzlprmft's advice, "do not ask questions that require long and elaborate answers", but I think it's important for the students to learn how to arrange the presentation of longer arguments, with shorter time available with respect to lectures. Many students respond well to this kind of question, and if the student is able to present the argument without hesitation, I let them go on, and I interrupt them only to discuss critical points. If, instead, the student stops, I start suggesting how to divide the topic in smaller portions.
In the few occasions in which a student really panicked, to the point of not being able to speak, I suggest them to have a walk, go to the bar, speak with a friend and then come back to continue the exam if they feel ok. And I recall them a few points about grades.