I'd like to have your opinion on the following.

I mainly answer questions about SQL queries. So sometimes there's not much to explain. I just post the solution and that's it. Sometimes minutes later someone else answers the same question with the exact same query as I wrote, but the other guy gets the upvotes.

No big deal, one could say, but I ask myself, what's up with those people. When I'm typing an answer and the "1 new answer has been posted" I click to see it, when it's the same as mine I stop. If I were to ask a question or read answers I wouldn't want to have to check for each answer if there's a difference. Not to mention the time wasted on this.

So my question is, should I flag those answers or not?

Or should a check for duplicate answers be implemented and the later one be automatically deleted?

I even once had the case, where a user unaccepted my answer and accepted another where the other one (who answered later of course) removed the line breaks. I asked why and the question asker answered "It seems more compact". That's where one can get angry, I can tell.


Okay, deleting duplicate answers may be a bit harsh, but wouldn't it be a nice feature to have a popup when posting a duplicate answer saying something like "If you don't have nothing more to add to the already existing answers, consider posting the answer at all." Of course in a more polite way :)

Another possibility would be to order the answers by timestamp additionally when ordered by votes is selected. I think most of the time users just upvote the first question they see when it's correct and don't bother reading the other answers.

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    Please include some examples; are you 100% certain they copied your answer? Commented Feb 18, 2013 at 14:28
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    If it's not an exact copy posted a significant amount of time later (not mere minutes) then I would just suggest you move on. Especially if the answer is somewhat trivial and could possibly be given by several users without it necessarily being a copy/paste scenario.
    – Bart
    Commented Feb 18, 2013 at 14:32
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    I see this answer of yours here stackoverflow.com/questions/14897896/… Both you and the other in my personal opinion you do not explain what you do, you just throw the code - for me, this is what can make your answers more genuine, to explain why and what you do.
    – Aristos
    Commented Feb 18, 2013 at 14:39
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    If we talk about the question mentioned by Aristos, what is definitely not okay is you accusing the other user of C&P. That user could have arrived at that solution by themselves easily. While they are the same, I don't see anything sticking out which cries C&P. You should take that opportunity to make your answer even better to stick out from all others. Commented Feb 18, 2013 at 14:45
  • @SulfurizedDemonbobby I agree it's not nice, I was angry and now that I've cooled down I actually feel bad about it. On the other hand, why doesn't he disagree?
    – tombom
    Commented Feb 18, 2013 at 14:52
  • @MartijnPieters Unfortunately I'm not able to find again the question where the line breaks were removed. And of course I can't be 100% sure it's copied, but I'm 100% sure it's exactly the same query, even with the same table and column aliases.
    – tombom
    Commented Feb 18, 2013 at 14:54
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    @tombom: Not everyone wants to argue with people on the internet. Additionally, what answer would you like to hear? "No, I didn't C&P your answer?", "Yes, I did it, what are you going to do about it?", "What the hell are you talking about, are you nuts?"...I actually find it preferable to not react on such comments...keeps the mods saner (and with less work). Commented Feb 18, 2013 at 14:59
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    Good point, I'll delete the comment and try to stay more calm in the future.
    – tombom
    Commented Feb 18, 2013 at 15:08
  • About the idea of ordering by timestamp: NO! SO explicitly started giving the timestamp less priority because of the Fastest Gun in the West problem. Changing that would bring back a lot of problems.
    – Linuxios
    Commented Feb 18, 2013 at 15:59
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    @tombom - If it makes you feel any better, your suspicions were well-founded. I've checked, and almost every answer by this user seems to have been copied from somewhere. They've been warned about this, and I'm in the process of removing the ones I can find. Commented Feb 18, 2013 at 16:30
  • Thanks that you are after this, Brad.
    – tombom
    Commented Feb 18, 2013 at 16:34

3 Answers 3


Personally, while this is extremely frustrating, I don't think this is a valid flag reason.

Flagging shouldn't be used to ensure that users being considerate. Flagging is for the more exceptional circumstances like spam, non-answers, and things that degrade the quality of SO.

However, that only applies when the answers are the same in code, and the code is a short snippet or small correction. In questions where answers are much more text than code, or where code is long and very original (not easy for anyone to just come up with the exact same without copy/paste). If someone exactly copy/pasted your two page explanation of a concept, that is plagiarism, and not valid. Please flag that.

Finally, there are those answers that say @... is perfectly correct, let me explain a little bit more. These are perfectly valid, as they are the solution to expanding on others answers instead of through huge, invalid edits.

TL;DR: If their answer is just the same in a simple snippet of code, don't flag. They could have easily come up with it on their own. If their answer is an exact duplicate of your two page explanation of half of comp sci, they are plagiarizing (only if it is identical word for word). Finally, if their answer builds on yours and gives you credit, it is perfectly valid.

Response to @tombom: While duplicate answers aren't good, if two people came to the same code around the same time, they both deserve to have their name on it in an answer. Additionally, duplicate answers should encourage the answerers to add to their answer to distinguish from the other answer, therefore removing the duplication. Try adding explanations, reasoning, etc.

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    Flagging shouldn't be used to ensure user politeness or conduct. That's not completely correct, you're free to flag comments/answers which are outright rude, insulting, noise or in any other way are against the TOS (and similar). Commented Feb 18, 2013 at 15:17
  • @Linuxios I agree with you, but I'd like to hear more opinions on the possibilities to avoid duplicate answers.
    – tombom
    Commented Feb 18, 2013 at 15:22
  • @SulfurizedDemonbobby: See edit.
    – Linuxios
    Commented Feb 18, 2013 at 15:25
  • @tombom: ...on the possibilities to avoid duplicate answers. Just checking, you're aware that everything on SE is licensed under CC-SA-BY? Commented Feb 18, 2013 at 15:26
  • @SulfurizedDemonbobby: And that means that if someone exactly copies your answer word for word and couldn't have gotten there themselves (because it's word for word), without attribution, that's breaking CC-SA-BY.
    – Linuxios
    Commented Feb 18, 2013 at 15:29
  • @Linuxios: Yes...just wanted to make sure if tombom knows that...because the question is not how to avoid duplicate answers but rather what to do if it happens. Commented Feb 18, 2013 at 15:30
  • @SulfurizedDemonbobby: Exactly.
    – Linuxios
    Commented Feb 18, 2013 at 15:31
  • As I state in my answer, please do flag for instances of copied wording without attribution. We do like to be aware of this, and sometimes we are the only ones who can remove plagiarized answers due to them attracting unsuspecting upvotes. We have warned or suspended a number of users for plagiarizing the content of others, and this is not something we tolerate here. Commented Feb 18, 2013 at 16:02
  • @BradLarson: Of course. Se the part of my answer about the difference between copied wording and posts and someone happening to reach the same three lines of SQL as you. There is a difference.
    – Linuxios
    Commented Feb 18, 2013 at 16:03

If the text(not code) of an answer is simple copy pasted, downvote it and leave a comment. Ask the user to quote and cite the source properly, and preferably elaborate on it. It is quite rare that the text from another answer exactly solves the first one. Even if it does, the answer may be answering a different question, and will look out of place as an answer to this one. In such cases, adding some question-specific "wrapper" text is a good idea. If the answer is a perfect answer for the question, it's quite likely that the questions are dupes.

As far as flagging goes--it depends on your site. On Physics or Chem if you flag something as plagiarism, I(a moderator) will add a comment+downvote, mark your flag as helpful, and come back in a day or two and delete if it hasn't been improved. However, this may not be the case with the moderators on the site you participate on.

  • Good point about different sites. Plagiarism in the Scientific community is a much bigger deal than a stolen explanation of the SQL SELECT operator. +1.
    – Linuxios
    Commented Feb 18, 2013 at 15:30

When it comes to short segments of code, remember that often there is only one optimal way to solve a given problem. If multiple people answer a question within minutes using similar code, that seems perfectly normal to me.

Copied wording is a different case. If someone has copied the exact words of another (not just paraphrased them), please flag that for us to look into (with the original source linked, if possible). We have a specific mod message template just for plagiarism, and will suspend users if this is a consistent, widespread pattern with them. One instance of genuine plagiarism often leads us to many others.

In this case, user2001117 answered within three minutes of you with identical code, so I'd give them the benefit of the doubt here. However, a much more concerning case would be this answer by the same user (now deleted) where they provided an answer an hour later than Iswanto San using their exact code, including the made-up table name and column that Iswanto San introduced as hypotheticals. That would be something I'd flag as suspicious.

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