Some comments on Prof. Rogaway's grading

My grading (at least when I do it myself) is intended to be a bit bimodal. Bimodal at the level of each problem or problem part. Specifically, I try to give more than half the possible points to any answer that is basically correct; and I try to give fewer than half the possible points for any answer that is basically wrong. I have observed that this translates to less partial credit than many students are used to.

As a consequence of the above, you are likely to get a better score getting half the problems fully correct than all the problems sort-of-correct (whatever sort-of-correct might mean in a technical domain, which I do not know).

In the "extreme" version of this grading methodology, your score is simply the number of problems that you fully and correctly solve. I like this idea, in principle, and would love to grade this way. But I have never found it to be feasible to really implement. I do approximate it more than many professors.

I grade this way because I like things to be right and I think you should know when you don't know something. A student should know if he or she understands a problem. If you can't solve a problem, that doesn't bother me at all (after all, I can't solve most problems I try to solve, either). But certainly you should know that you can't solve the problem. Maybe, in time, you'll get it. When you do, you can feel happy. There should be a moment when you realize: I get it! Perhaps what make our species not just ignorant but really breathtakingly ignorant is that we not only know very little, but most of us haven't the slightest idea just how little we know. How can we be humble and curious and grow and yet not know if we're right or wrong in a domain as simple and detached from the real world as a mathematically abstracted technical problem?

One more comment. One student told me that he left some True/False questions blank because he was worried about getting negative points for wrong answers. Let me emphasize that I never give so many negative points for the wrong answer on a True/False question so as to be "punitive" about guessing: in a no-justification-needed True/False question, it will still be in your interest, statistically, to guess. The purpose of "taking off" for wrong answers in True/False questions is just to normalize scores so that "knowing nothing" doesn't give you an expected 50%. (After all, 50% isn't much worse than the median grade I often see on exams!) In any case, for True/False questions with justifications, I never give negative points for wrong answers because a student can't guess a convincing justification. The justification has to be present and correct to earn points for the problem.

Phil Rogaway