Is it a good thing to erase wrong answer?

Question

Recently, user answered this question Inequality for Distribution of points in space, but his solution was wrong. (I don't know in what detail am I supposed to explain things here since this is my first post in meta, but basically, he swapped $\sin$ with $\cos$ and then miscalculated something. If needed, I can provide more detail)

I read his answer and saw it was wrong, so I commented on that. He almost immediately erased the answer. I think it would have been better if the answer stayed there - it showed one false solution using a wrong counterexample that probably someone other would come up with, and then I commented on why it was wrong both intuitively and where it was miscalculated.

To sum up, I think it was an educative-to-read wrong solution. Is it better to erase such an answer or to leave it be?

Now for the other thing about the same question - and I have a feeling that I should maybe start a new thread regarding that issue, if yes please tell me and I will do so, but it also seems appropriate to tell it here.

One user posts a smart and correct solution saying "no" to the original question, a day after some other user posts wrong solution saying "yes" to the original question, and the guy that originally posted the question accepts the wrong solution as the correct one. It was virtually impossible he didn't see the correct reply saying "no" since it was older.

Two things are confusing me with this. Firstly, the user that came second and wrote wrong solution. I mean, he (could have) read the correct solution. Why post another wrong solution after that? Or if he thinks his is correct, why not trying to find an error in the previous solution and commenting on it?

And of course, other thing, why did the guy who posted the question accept the wrong solution? Oh, and also, since it was a question with bounty on it, and accepted answer now has 2 down votes, did he still receive the bounty?

Also, to the people that already got into New year, happy New year! To others, have a great Eve! :-)

Answer 1

Regarding your question about keeping flawed answers: there are several reasons people delete their answers once a fundamental flaw has been pointed out:

• the question will not appear in the Unanswered queue if it has an upvoted incorrect answer, so deleting the flawed approach allows the question to receive more attention;
• the answer author may want to fix the answer, but needs more time to work on the fix. Deleting the answer is a cleaner way to avoid confusion than alternatives (like putting a "Don't look at this yet! It's wrong!" message at the top of the answer).
• having a wrong answer attached to one's name can be embarrassing.

I agree that it might make sense to keep some wrong answers around, if the mistake in the answer is instructive (and the answer is edited to clearly mark it as a failed solution attempt). But I also think that the decision should be up to the answer author on a case-by-case basis.

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Regarding why users accept incorrect answers despite being presented with a correct alternative: who knows? Users do all kinds of irrational things.

Answer 2

When someone points out that an answer of mine is wrong I usually delete it. But if it's wrong in an interesting or useful way I edit it to say so and leave it.

Here's one example: Symmetry group of a cube: $O_h \cong O \times C_2$ . I don't know whether it was accepted before or after my edit.

Answer 3

Yes and No.

Keeping an incorrect answer prevents the asker from getting the correct answer as people won't see it in the unanswered queue, so for that reason alone the answer should be removed.

However, there may be times in which a minor error in an answer once pointed out in comments or via an edit makes the answer good enough for the asker.

Ultimately it depends on the asker at least from a functional standpoint of the immediate goal of getting the asker their answer. From a general standpoint of wanting the site to be useful to future visitors though, it all depends on the quality of the bad answer.

I have been the victim of bad answers in the past, and I would have preferred the answeree asking "would you like me to delete it". I would have responded "yes, and if you'd like I'll alert you when a correct answer comes around so that way you can choose to undelete without causing problems".

Of course, as always the asker is completely allowed to delete their incorrect answer whenever they wish. If for some reason it gets falsely accepted (and then continues to accrue downvotes)... I'd ask for people with delete vote powers.