I agree with the first part of the answer (let the grade stand), but not the second (adding an additional assignment to maintain the grade).

Will you actually downgrade the test if the student doesn't come back with the requested paper in a week?

The part about additional work still has most, probably all, of the drawbacks of simply lowering the grade. If you did that to me, I would take that as a lesson to keep my mouth shut and not talk to the teacher. Many students, including myself when I was one, despise writing assignments no matter the length.

As a recent student, I disagree with the second part. That just causes resentment in the fact that I came to ask a question and get punished for it, with no fault of mine.

@Aaron, despise it as much as you like. But it is an important type of learning. It wouldn't be something I "did" to you. It was offering a deal. You are free to reject the deal.

@DanielR.Collins, I would cross the bridge when I came to it, but probably yes. If we make a deal and you don't follow through, then the consequences are pretty clear. Would I also entertain counter suggestions from a student. Sure, why not. I'd rather they learn something, no matter how.

You are free to reject the deal. <--- I would simply never come to speak to you again about an issue like this and would advise fellow students not to. I would speak freely to fellow students about it and to other faculty members too, if a similar subject came up. Why wouldn't you explain to the student why the mistake happened and what additional exercises/work you would do to undertake to make sure it doesn't happen again? That would sound like a better 'learning experience' to me ;-)

I am quite surprised at "my job is teaching, not grading" statement. Maybe you have that luxury, but here (in the UK), as a member of faculty (teaching+research), you are required to pass a teaching qualification which explicitly covers assessment and grading as one of its elements (where performing teaching activities is another one, of the four or five elements covered in total).

@Buffy If you propose it and the student doesn't accept it, but you still downgrade, it's not a deal, it's a one-sided ultimatum. And your example would feel exactly like this to me, godfather, an offer one cannot reject. (Not meant as bashing but as feedback about the likely way this is perceived).

@FrankHopkins, and yet you have absolutely no idea how I interact with my students. Some of these comments are actually sort of funny, considering.

@Buffy indeed we don't know and can only judge based on your description - and that standing alone would irk me as a student and not help/motivate me to learn. Maybe you can soften that with your overall tone/behaviour etc. and judging by all I've read from you so far, in general you seem to be somewhat thoughtful (my rough impression), but that doesn't take away from the impression the "offer" on its own makes. And your general approach sounds great, as it also seems only to allow for improvement, while the offer implies a downgrade unless the student follows up.

@FrankHopkins, don't forget that the student apparently gave a completely wrong answer on an exam. It isn't a downgrade. It is an offer of lenience if the student can show they have learned what they missed. It is all about the education and nothing, really, about the grading. I had students practically living in my office for support on their work. But they had to do the work.

Actually, @penelope, for what it's worth, I worked with some people from the UK on developing meaningful advice to educators on assessment. Papers, and stuff were written. And, you are somehow implying that you don't have the "luxury" of teaching in UK? Somehow I hope that ain't the case.

-1 for the possibility of downgrading the student (as other commenters have explained).

@Buffy the student had the grade and had he not taken the action to try to clarify the correct answer,he'd still have it. If he needs to put in additional work for keeping his grade because he was interested to learn and fully understand the question (or just to fight for his understanding and that way also learn indirectly), that's a "punishment" for asking. Simple lesson for the student: be quiet when you're not sure. And if the student needs to show that they understand, it's not about learning, it's about grading and measuring. Anyway, we disagree here, which is fine, have a nice day.

Your answer uses the expression "creating a learning moment". Yet, in one of your comments, you state that your offer is an opportunity to "show they have learned what they missed". This dual function is what makes your answer so problematic. You may believe what you're offering is a learning opportunity, but in effect you're mostly assigning a gradable task, testing their learning progress. It's pretty much established that exam situations make rather poor learning moments, so if your primary intention is to teach and not to grade, your chosen solution is likely to betray your intention.

Buffy, I was responding to your statement "I viewed my job as one of teaching, not grading." I was saying that I don't have the luxury of saying I don't consider grading part of my job, as grading is explicitly included in the teaching qualification academics have to obtain here. In the ideal world, I'd also love to teach only for the students to learn. In reality, they actually assess me on my assessment skills, in a way, and they are explicitly included in the teaching duties in the UK. Sorry if I was unclear :/

That: I viewed my job as one of teaching, not grading.

@Heutl, I hope you are willing to stipulate that the "unfair" professor you all knew about wasn't actually me. You are making characterizations here for which you have no (scientific) evidence.

@Heutl, I don't know how experienced you are, but can you imagine how many students I dealt with in more than 40 years? I never figured it, but it is in the thousands, certainly. Actually, many of my papers are about pedagogy as well. It was a main focus of my career (after I learned how to do it properly). And, full disclosure, there were some complaints along the way. No one avoids it. Just look at the comments here, for example.