When is it appropriate to edit another user's answer?

Question

I had an incident recently where another user decided my answer was wrong, and simply edited my answer to change it, and commented on the question that it was previously wrong, without any explanation why. Because there was no comment on my answer, I didn't get any message to indicate what had happened, I only noticed by chance.

Frankly, I feel it's more than a little inappropriate to change the substance of someone else's answer without any prior discussion; am I right in thinking the user in question should have commented on what the problem was in his opinion, and/or posted his own answer rather than simply changing mine? I can probably see why he felt it was wrong, but depending on the context of the OP's question, my original answer could well have been exactly what he was looking for.

Hence my question; I've edited questions myself purely for formatting or spelling, but never to alter the substance of the content, but aside from making a question/answer easier to read, I can't see any other justification for it. Is it poor etiquette to modify another user's answers in this way, especially without qualifying your reasons?

Answer 1

Edits should never change the content of a post, just its readability.

If your answer had an error, a comment should have been left alerting you to it so that you could fix it.

Answer 2

Looking at the exact example: How to show a character n times in XSLT?

I would have to say this was poor etiquette. Instead he should have just commented on your answer with his concern and you could choose to address it or not. He could have also added another answer of his improved version that explains why he things the changes are needed and let the community decide.

Lastly, commenting on the question was pointless, it should have a least been on the answer and should have given a reason why.

Answer 3

I agree with @Al Everett, in that an answer should only be edited for readability.

There are examples where plainly incorrect answers get upvoted.

But over time, its easy to see what the best answer is.

I'm confused why @Alejandro thought he knew the correct answer, but decided to do an edit instead.

Either way, I think its funny that I asked something along these lines a while ago...

Answer 4

I don't know XSL well enough to understand what the change was.

In general: occasionally, if someone's answer is mostly right but has a small mistake in it, I'll just correct instead of causing a fuss. An example of a "small mistake" might be maybe a syntax error in a C++ code sample.

I wouldn't want to edit it so much that it becomes a different answer, though.

I'm less likely to add to an existing question: I'd more likely do that (e.g. if I want to add a caveat, or mention a special case, or something ) as a commment, than by adding to the answer text.

Answer 5

Some folks seem to think that it is never appropriate to change the content of an answer. I would suggest that there is one (and this is the only time I've done it): When an answer is unequivocally and dangerously wrong.

A few weeks ago I came across an answer that was blatantly against Apple's documentation. It was accepted and upvoted. I provided citation and changed the answer. IMO, in this case it's the right thing to do because the question was factual, not subjective, and the existing answer would have led inquisitive programmers into very bad situations.

Yes, perhaps I could have downvoted it, and provided my own answer, and hoped it got upvoted. But in the meantime, how many developers would have been receiving and acting on incorrect information? That's much more important to me than someone getting their feelings hurt.

My point is, I think there's a line somewhere after which it's not only okay, but the responsible action. For argument's sake, what if someone on driving.stackexchange.com asked "Which side of the road should I drive on in the US?" and the accepted answer was "On the left" with 50 upvotes, is it okay then?

Answer 6

Another occasion when it may be correct to edit another user's answer (not changing but adding content):

I sometimes edit other people's answers by adding content.

If it feels that the answer is generally correct and adding another answer does not seem right (as it would only duplicate most of that corerct answer) and there is a point where that answer can be improved, or some content can be added, I just add it.

Example, the edit of zerkms' answer here: Update an entire row in MySQL

It may appear wrong to some but I haven't got negative feedback on such actions. And if the answerer really thinks that the edit inappropriate or wrong, he can always rollback.