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Duplicate questions are "solved" — it's clear what to do with them, there're tools to deal with them... but what happens when two users post the same answer? This happens a fair bit, particularly on questions with simple answers ("Click this button"-type ones).

Do we upvote both answers, since they are both correct? Do we upvote the first one (although if the answers were posted within a few minutes of each other, after an hour it's impossible to tell as they both show up as "answered 1 hour ago")? Do we upvote the currently highest voted one? Do we upvote one and downvote the other? Do we flag one (seems a little excessive)? Something else?

  • 4
    It is possible to tell which was asked first, it has a lower number in it's permalink, it's just not easy to tell the difference. – Brad Gilbert Jun 30 '09 at 14:04
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    @Brad: You can also hover your mouse over the "answered an hour ago" text that appears above the user's name to get the exact time stamp the answer was posted. – Bill the Lizard Jun 30 '09 at 14:27
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    Heh, I've never noticed that timestamp before, despite using the site for.. err.. 10 months – dbr Jun 30 '09 at 15:05
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    You can also just sort by newest or oldest, and it should put them in the right order even if it lists "X hours" for both. – gnostradamus Jun 30 '09 at 15:49
  • Vote for the one that is better. Even if their contents are identical, vote for the one that is more grammatically correct, has better formatting, uses markup instead of just plain-text, has a screenshot, and so on. – Synetech Aug 15 '11 at 1:19
30

This is the age old Fastest Gun In The West problem.

Those who get the answer first should obviously be rewarded for their speed, but if there are instances where users post the same thing within seconds within one another, I will tend to upvote all of them. If it's within a few minutes, I will not be so lenient because that should have been enough time to review the already posted answers or load any new answers that were written during the construction of your own.

Seconds apart = close enough to reward both

Minutes apart = not close enough, fastest should get the upvote.

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    But then there's still two answers that say the same thing. It would be best if we could merge them somehow. – endolith May 16 '12 at 14:21
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    What about several days / months / years between the answers? For example, the answer of simao and the answer of Calmarius to the same question? Should the answer of Calmarius be downvoted for posting more or less exactly the same answer several years later? – Martin Thoma Oct 29 '15 at 11:29
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    Well, I saw many times the following strategy: one quickly puts an incomplete answer and then edits it several times later. Your approach would reward this strategy. One could go further - put wrong or incomplete answer to be the first and then edit it to copy a correct answer from someone else. In fact there is no way to determine who gave the correct or the best answer first – Andrej Adamenko Nov 26 '15 at 8:00
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    @MartinThoma I see this in this answer today, and see it quite often. I find it really irritating (to say the least). I do not understand why there are no flag options for duplicate answers... it is stupid... – Jonathan Jul 7 '16 at 14:30
  • Could coding be added to flag duplicate answers, and then the site would group them with a "X other answers say the same thing" that has the other answers collapsed? That way no one is shocked to find their answer deleted, yet they also don't clutter the comparison of answers by having numerous equal answers up top, or alternatively different ratings on the same answer. – JeopardyTempest Feb 13 '17 at 2:27
  • What do I do if I post an answer that was already there and it is being downvoted, should I delete it and will it help prevent an answer ban? – FluorescentGreen5 Mar 10 '17 at 4:59
  • I had a problem where someone duplicated my answer and got upvotes while I got downvotes. The content my answer and their's was no different. What should I do? – user373522 Oct 26 '17 at 21:06
  • This is wrong, rewarding is important, but it should not affect the readers. The votes doing two things - reward and sort. I believe first answer should be rewarded but the best answer should be up-voted. I'm down-voting your answer because I disagree, but I'd like to reward you for your ideas. – Yevgeniy Afanasyev Dec 18 '18 at 23:10
  • What I do see a lot is new users posting duplicate answers seeking points since just 1 upvote take several downvotes to nullify it. I understand that some dupes can be actually better than first ones, it's not a grey area anymore when an answer is posted months/years after the accepted adding nothing of new. There should be a close/delete dupe low-quality answer. – Andre Figueiredo Jan 28 at 2:50
14

This is an old topic, which wasn't active for a bit, but it is still live.

The age-old Fastest Gun In The West problem was mentioned. I've found a case which is the exact opposite of it. In the question How to get the number of elements in a list in Python? the answer was given, and two years after another answer was given, which contained exactly the same solution, only the example code a bit modified.

This post brings nothing new to the topic, but because this is one of the most common learner's questions, it got a few upvotes. Someone is even curious why it got any downvotes...

I've searched for 'duplicate answer' flag, but such flag doesn't exist. I've commented, flagged as requiring moderator attention and downvoted. Maybe a bit exaggerated, but the reputation from such answers is a stowaway effect.

  • It's also pretty annoying when the duplicate is marked as the correct answer because then you downvotes won't bring the original above the duplicate. – c1moore Jan 29 at 23:14
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    There should be a 'duplicate answer' flag. Not only are duplicate answers not adding any value to the topic, they are actually bloating it, making the unique answers less visible. It would be neat to have a merge method where in case of a fastest gun condition both authors are rewarded for the same question – MuhsinFatih Apr 14 at 4:25
5

I started to comment on the later ones. This will encourage them hopefully to either withdraw or enhance the answer to add value. (if I can't see which is the later one, I prefer to comment on the underdog.)

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    What kind of comment? – endolith May 16 '12 at 14:21
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    I crafted a comment: "Hi, Welcome to (ExchangeSite) As explained in the tour (with link for appropriate tour), this site is a repository of useful questions and their answers. Your answer is not essentially different from (the accepted answer, (this other answer), etc) and not very useful since it does not add any new value or information. Please avoid writing duplicate answers, either edit your answer to add value or delete it altogether, this will ensure all questions and answers on the site remain useful not scattered/duplicated." – user403372 Oct 3 '18 at 5:49
5

Personally I upvote the response which answers the question most completely and with the most detail (not always the same thing). If there are 2 responses which are simply "click here" with out any value added, neither get the vote.

I have on at least one occasion had my response trump 2 preexisting responses which were both technically correct, but not very useful. I believe this is because I included more background, a code example and link to further information.

That, IMO, is the type of answer that should be, and in many cases is the type of response that gets rewarded over time.

3

I usually wait a minute to see what user takes the effort to expand his answer. Then upvote that person. Or if someone comes along with an expanded well thought out answer.

2

I had this happen just yesterday (my answer happened to be first, but the other user got one upvote before me, so naturally his answer got the rest of the upvotes). As the duplicater (who lost the vote count) I just removed my answer.

  • Periodically I go through my answers and delete those that have no votes. I leave the ones with up-votes even if they are very similar to other answers on the assumption that somebody found it useful so there must be something in my answer that's not in anyone else's. – ChrisF Jun 30 '09 at 13:29
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    @ChrisF: I generally don't delete my answers as long as they include some piece of information that others haven't mentioned. Even if they aren't up-voted. Otherwise, maybe. I'm lazy, though, and going through my old answers "...sounds suspiciously like work." (er... that makes more sense if you know "That sounds suspiciously like work." is my catchphrase) – Powerlord Jun 30 '09 at 13:53
1

Other than the fastest gun in the west problem, this also happens for very old questions with many upvotes. As an example see this: What's the difference between @Component, @Repository & @Service annotations in Spring?.

It has 24 Answers, all of which saying the same. While there is some merit in finding the best way to express an answer or solution, in this case further answer were probably given with the sole intent of gather reputation or badges.

This may not be a huge problem, but it can have significant effects:

  • when new solutions become available because of technology changes, a new repaired answer will take time to gather enough votes to become visible
  • All these duplicate answers make Stackexchange sites look silly and make the community look focussed on reputation gain, not on producing quality.
  • This happens for highly visible / visited questions
1

(My answer sounds more like a proposal so maybe I should post it separately?)

When the question is old and it's been awhile and very-similar/dupe answers still exist and haven't been edited to improve quality and distinguish from other answers, it would be neat to have a way to flag X answers as dupe and have a way to vote for which should stay while the others should go down.

Eg. here: The three last answers (by Swaff, Kim and Smallgods) are almost identical and keeping the 3 of them doesn't provide any additional value and even add unwanted noise:

How to empty a list in C#?

As others mentioned, it would be neat having a proper way of dealing with those. (Or an officially preferred way with existing tool)

0

Having just been 'second place' on an answer that was char for char identical (bar flags), separated by by 23 seconds, with consecutive answer ids. I wonder if there's any mileage in the answer submission action alerting the submitter to any answers that have been submitted since they started writing their own answer?

  • The "1 new answer has been posted" banner should do this, although it only updated periodically. Not sure an on-post alert is terribly useful, as you can always just delete your own answer should it be a dupe – dbr Aug 5 '09 at 15:05

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