I am aware of this similar question on Meta Stack Overflow, but it mostly deals with duplicate answers that come about due to the race to answer, which is outside of the scope of my question (which deals with answers made a lengthy period afterwards).

I have, in the past, flagged answers that are merely a subset of the same information contained within a previous answer, where the two answers were not both posted within a reasonable timeframe of each other.

Previously this has not been a problem, and my flags under this context were approved, but yesterday I had a flag of this type declined as being on principle not suitable for the flagging system.

Is appropriate to flag answers that are merely repeating the same information given a significant time previously, and, by which, add nothing new? If not, are answers that are merely repetitions of previously given information considered a non-issue?


Those are, I find, hard to deal with because:

  • The answers are answers, so flagging as not an answer isn't appropriate at all.
  • The answers aren't wrong, misleading or otherwise technically/factually incorrect, so a downvote doesn't necessarily seem appropriate.
  • Very low quality doesn't necessarily apply either, they're often "salvageable" with an edit.
  • But they are, to me, annoying because they bring nothing new.

There is no "doesn't add anything new" flag reason, and I guess that makes some sort of sense: unless the answer has some other flag- or downvote-worthy characteristics, does it actually do any harm?

Having several answers that explain essentially the same thing, but worded/presented differently isn't intrinsically bad. In fact, it can actually be good, just like keeping duplicate questions visible and indexed - makes the information more "findable". Having something explained in a few different ways makes it more likely to be well understood.

That being said, poor/barely mediocre late answers that regurgitate things that have already been said shouldn't be encouraged. Here's a few thoughts:

  • If the answer is just a copy/paste of an existing one, flag it and explain that's the reason why you're flagging - a word-for-word duplicate doesn't add anything at all. Those usually lack any attribution, so that's another reason for a flag ("plagiarism").

    In all cases where you're flagging a post that, when taken in isolation, doesn't really look like it's flag-worthy, make your flag message as clear as you can.

  • If the quality of the answer is also very poor, i.e. formatted like a blob of goo held together with txtspk that requires several parses to even grep what it's about, there's a flag (and review queue) for that.

  • Comment. Let the poster know that repeating information without anything new doesn't help and isn't the kind of contributions we're after. As always, be nice. Try and steer the user into making their post better, don't flame them for being a noob. Stack Exchange sites don't work like most of the other sites out there, some new users need a bit of "tutoring" to really understand how we work, and everyone can help with that.

  • Downvote. The tooltip does say: "this answer is not useful". Matches the symptoms if it truly doesn't add anything of value. For the more extreme cases, remember that downvotes as well as deletions are taken into account for the automated post bans. So when you see something that's simply not useful at all, downvote. The problem will eventually fix itself it the user doesn't adjust to our site's guidelines.

(The two last bullet points are not mutually exclusive.)


I generally delete answers that are duplicates of existing answers, but only if the answer was way later (usually it's days or months later, but at least an hour at minimum). I don't really agree with mattdm's endorsement of multiple answers presenting the same information phrased differently; I'd rather each answer be a different point, so somebody scrolling through them doesn't have to keep thinking "this is useless, I just read this five seconds ago on the last answer"


If you want to flag answers that give no new information, shouldn't the time difference matter in this case?

In simple questions two or three exact same answers appear very fast. In stackoverflow for example almost in seconds. In unix/linux quite fast also.

So if there are two answers given on the same minute, which one is the obsolete one? They have probably been written at the same time.

Long answers are a different case. You spend 10minutes writing a good answer, and then at the same time / in that time, somebody else gives the same information. Should you be rewarded with a flag then? In long answers, even tough the information might be the same, the format might differ and be more easily understandable to different readers.

  • I'm only asking about the latter. I think in the former case, it can be resolved just using the voting system. – Chris Down May 15 '13 at 7:22

Overall, I don't think these answers are really a problem. Just leave them and they won't rise to the top. If the answer is really just plagiarizing the existing content in a literal way, then it might be appropriate for flagging.

In other cases, though, and I think the flagged post that brought this question qualifies, the new answers are a good-faith attempt to present the same information with a better structure or wording. Even if the actual underlying information is the same, this can still be positive. (One could of course edit the existing answers, but there's a degree of change in tone of voice, ordering of points, etc., where an edit isn't really right.)

  • 2
    In How to count the number of a specific character in each line? prasan's answer is essentially the same as Loki Astari's answer. Posted more than an year and half after the original one, prasan's answer adds no value, but already got an upvote. Which should be received by Loki Astari's answer. I think that is not fair. – manatwork May 12 '13 at 14:53
  • Right, that's an example of a duplicate answer that clearly doesn't add anything. There's no attempt to explain the same information differently. But that said, I wouldn't worry so much about "fair". Maybe someone upvoted noth answers. Or even if not, there are plenty of upvotes in the world. – mattdm May 12 '13 at 15:03
  • Well, okay then. I know when I'm outvoted. :) – mattdm May 16 '13 at 21:15

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .