How to handle duplicate answers that add nothing?

Question

I'm not talking about exact copying, failure to give credit, or one person passing off another person's answer as their own.

Rather, I'd like to know what the best practice is when one user answers a question with an answer that is either:

• effectively identical to an existing answer, and not really stylistically different (so there is nothing about it that would make it preferable to the existing answer)

• effectively identical to an existing answer, just with some information removed (but the information that was removed was useful, and was not false, misleading, or even confusing)

I think this doesn't happen only (or even primarily) from one user copying another user's answer. Rather, when a question has a simple enough answer, answers that look extremely similar may be posted ...if subsequent answerers don't look to see what other answers have been posted, first.

(Another possibility is a user starting to compose a 2-line answer, but taking an hour or more to finish it, and then another answer that is similar being posted. I consider this to be possible, but unlikely.)

As one example of this, consider this question, where this answer was posted, and then about an hour later this answer was posted._{I've edited one of those answers for unrelated reasons, to improve it, so this is no longer a good example. If anyone can replace it with another/others, great! If anybody thinks this whole text should just be edited out entirely from this meta question, I'm OK with that too.}

Should these be...

• just left alone?

• flagged for moderator attention?

• downvoted?

• commented on?

• or something else?

I'm reluctant to downvote something like this because the answer is not any of the following: wrong, misleading or otherwise dangerous to users, very low quality, or not really an answer to the question that was asked. I usually try to downvote answers that meet any of those descriptions (and cannot readily be improved), and to not downvote answers otherwise.

Sometimes these second, equivalent answers get upvoted, and are then shown higher than the original answers, so they're upvoted some more. This seems counterproductive to the goal of getting us to answer questions that still need answers (whether or not they already have answers), and then moving on to other questions that need answers.

Please note that I do not believe this is the same as the situation discussed here. In this situation I'm asking about, subsequent answers are posted with the same or less information. In that situation, subsequent answers are posted with more information or partially overlapping information.

Answer 1

For most users that have a problems reviewing answers and checking who is what in a duplicate posted answer with the same content there is a tool you can use to check the exact timing it took for stuff to happen in a post.

It is called timeline an can be accessed by going to a post's revisions page and replacing revision with timeline in the URL, ie:

http://meta.askubuntu.com/posts/3402/timeline

will show you the exact times for creation, modifications, votes and all the rest for this question.

That is probably the best way to check for possible plagiarism in answers and will help you make up your mind in what to do next.

If I spot identical post I normally use this tool to make up my mind, up vote the post I think deserves more and leave the others alone. If there is need to downvote it will happen but not as often as I would like to admit.

Answer 2

I usually vote for the one with more information (especially references).

In this case one is just a command without explaining, and the other one assumes you have synaptic installed but doesn't show how to install it. Personally I feel both of those answers are incomplete.

• Semi-related: Fastest Gun in the West Problem

Answer 3

IMO as long as the timestamps indicate the lower-information answer as a "fastest gun in the west"-type thing and it is not an unattributed copy-paste, it should be left alone to its own democratic fate by the community (votes) and the questioner (accept).

• If the answer came in more than a few minutes - say 20-30 -- later, to me it shows that the poster more than likely did not read the existing more complete answer or simply ignored it. In that case, I would downvote it with a comment indicating why, and recommending either a self-delete, or a more extensive edit (adding unique information) to cure the downvote.

• As Eliah mentions, there certainly are cases where such later-and-with-less-information answers get upvoted more and sometimes even accepted. I think those should still be left alone, trusting the law of averages and a somewhat intelligent reader who will return to read the alternatives if the accepted/most-upvotes answer doesn't do the job. I would certainly upvote the more informative answer(s) though -- as I usually do anyway -- while not voting on the later-with-less answer.

• For new answerers who might get agitated in the above situation when theirs is the older answer -- as I was a while ago -- here's a reassuring example of democracy in action in a somewhat similar situation. Note that the answer was initially unaccepted, got Populist and then seems to have even convinced the OP to change his mind and switch his accept.

Answer 4

The users of Ask Ubuntu should decide in most cases.

And of course the timeline feature can be used to check possible plagiarism in answers.