Consider this scenario:

  1. A question, X, is asked.
  2. An expert reads the question and checks it is not a duplicate.
  3. The expert writes a good answer, A.
  4. That answer really is good; it receives up-votes.
  5. Another expert realises that question X is actually a duplicate of canonical question Y. She votes to close X as a duplicate of Y.
  6. The community agrees, and X is closed as a duplicate.
  7. The expert who wrote answer A agrees. If she has known they were duplicates she would have answered Y rather than _X. She wants her answer A to be an answer of canonical question Y rather than of duplicate X. That way the canonical question will benefit from their good answer, and she makes the Internet a better place™.

At present, the expert who wrote answer A has no means for doing this. Merging of any kind is for moderators only. As far as I can see, merges almost never happen. Probably because moderators have more important things to do, and because of fear of messing up questions that are not quite duplicates.

The writer of answer A can not simply copy the text of her answer from X to Y. It seems that SE automatically detects copies; a moderator will delete the new copy (this has happened to me). If she copies the text and then deletes the original, so there is only one copy live, in an attempt to prevent a moderator intervening, she will lose the deserved reputation she earned on the original: a disincentive to do The Right Thing. We want gamification to encourage good behaviours, not discourage them.

I propose that when a question is closed as a duplicate of another (canonical) question, each answerer of the duplicate question has the option to move their answer from the duplicate to the canonical question. This move in effect deletes their answer on the duplicate. However, unlike a copy-then-delete, votes on the answer move too.

The only tricky part of this is how to deal with an answer that has been selected as the accepted answer. The simplest solution is that the moved question looses its status as the accepted answer, and the answerer looses 15 reputation. Another option is that the question looses its status as the accepted answer, and the question receives 2 up-votes as compensation, giving a net gain of 5 reputation.

The mass of duplicate questions is created *broken windows". The accepted solution to that problem is better merging, but clearly hardly any merging is being done by the moderators.

  • 6
    How would your feature protect the canonical question from amassing a ton of duplicate answers?
    – yannis
    Commented Apr 5, 2016 at 13:21
  • " would your feature protect the canonical question from amassing a ton of duplicate answers?" A mass of duplicate answers spread over multiple questions is worse than the same mass of answers to one canonical question.
    – Raedwald
    Commented Apr 5, 2016 at 14:35
  • 4
    Duplicate answers cause noise. They are not universally beneficial.
    – Catija
    Commented Apr 5, 2016 at 14:41
  • 3
    Care to explain why you think that is @Raedwald? Because to me, spamming a canonical question with duplicate answers ad nauseum doesn't sound like a good thing...
    – yannis
    Commented Apr 5, 2016 at 14:53

2 Answers 2


I don't see this as being something that needs to be taken out of moderator hands. If the OP of the answer wants to have it moved, they can certainly flag it and request that it be merged onto the current answer. This prevents the issues of ending up with duplicate or near duplicate answers...

I do think that giving mods (or sufficiently high-rep users, perhaps) the ability (if they don't have it already) to move (or recommend moving) an answer from a dupe to the original question without merging the two would be beneficial. This gives the mod the ability to double check whether the answer is a dupe and to make certain that the answer actually addresses all of the points in the original question to an acceptable degree.

Allowing any user to do this would likely be problematic, so I do not support that part of the proposal.

  • "dupe questions are useful" only as sign posts to canonical questions.
    – Raedwald
    Commented Apr 5, 2016 at 14:36
  • "When you merge entire questions" this proposal is not about merging entire questions.
    – Raedwald
    Commented Apr 5, 2016 at 14:37
  • @Raedwald I'm not a mod so I don't know what the process is but my understanding is that "merging" is an "entire question" process. You can't partially merge two questions.
    – Catija
    Commented Apr 5, 2016 at 14:38
  • When you merge entire questions, you lose that additional terminology that may have been used in the dupe version. - actually not the case. What happens is that the source of the merge ends up a "stub" containing only the question but with a banner notice to the target (like a normal dupe but with "this has been merged" added). All answers/comments effectively get re-associated with the target post. Mods barely use the tool as it's an all or nothing (and practically undoable) process. Being able to move individual answers might be a thing... Commented Apr 5, 2016 at 14:43
  • ... however, I'd reckon it'd cause so much headache however it was done as to be implausible - duplicate answers, confusion about where an answer went if someone bookmarked it, and the number of use cases I believe would be very low. Commented Apr 5, 2016 at 14:45
  • @JonClements Thanks for the clarification. I don't think I've ever seen a merged dupe so I assumed that they disappear into the ether. It's good to know that I'm wrong on that front.
    – Catija
    Commented Apr 5, 2016 at 14:47
  • @Catija see stackoverflow.com/questions/10955703/… for an example of how it looks Commented Apr 5, 2016 at 14:51
  • @JonClements For what it's worth, on cooking I merge duplicates now and then, and the times when I don't, I generally wouldn't want to see any of the answers moved without adjustment.
    – Cascabel
    Commented Apr 5, 2016 at 16:28

I'm not really in favor of this proposal.

Let's look at the status quo from a slightly different perspective. There are a few possibilities on duplicate questions.

  • Answers don't make perfect sense on both questions. In my experience, this is by far the most common kind of duplicate. If desired, users should move answers manually, editing as necessary to match the canonical (this is important!), and copy-detection shouldn't flag anything. No point in moderator merges or a manual per-user answer move, since users really need to put in the work to edit.

  • All answers make perfect sense on both questions.. This is reasonably rare, but does happen. Moderators can merge, just flag to ask for it. And if there's no value in merging, perhaps because it's a simple question with nothing to gain from the additional answers, so be it. (Side note: depending on the site, your mods may be willing to round nearly-perfect up to perfect. I usually end up making small adjustments to answers after merging.)

  • Some answers make sense on both questions, some don't. This seems less common. Usually either the questions have some differences and the answers inevitably do too (the first bullet), or the questions themselves are so identical that the answers can't help but match both (the second bullet). If it does happen, we're still not totally out of luck: you can find things to edit and improve and then repost without worrying about copy detection, or you can delete and repost and accept the reputation loss, or you can post the direct copy and be prepared to explain to a mod if the system does flag it.

So, what do we have to gain from this feature? Essentially, things get slightly easier for users in the third, less-common case. If people's answers truly didn't need adjustment at all (but other answers would, so a mod won't merge), they'd have an easier path. But they have a path even without this feature.

And what do we have to lose? Things potentially get a lot worse in the common first case. People can easily do the wrong thing, moving their answers without editing when they actually need adjustment. They'd essentially be rewarded for doing so: they'd keep their rep and rank favorably on the target question. We'd end up with more mismatched answers on the canonical question, and even in the ideal case, more duplicate answers on it.

So bottom line, I'd rather not see this feature. The hypothetical "do the right thing" user in your question can do the right thing even without it, and the current system prevents other less-noble users from doing the wrong thing. And it becomes less and less of a problem as we close duplicates faster; I'd rather encourage people to check more carefully before answering a soon-to-be-closed question than reward them for quickly answering.

  • "Moderators can merge" my reason for this proposal is that this does not happen.
    – Raedwald
    Commented Apr 5, 2016 at 16:23
  • "Users can move answers manually" as I pointed out, this gets your copy deleted.
    – Raedwald
    Commented Apr 5, 2016 at 16:23
  • @Raedwald Have you flagged all questions you believe should be merged, and had moderators decide not to merge them? Have you discussed with them why they didn't merge?
    – Cascabel
    Commented Apr 5, 2016 at 16:24
  • @Raedwald As I pointed out, you don't have to make an exact copy. It is totally possible to move your answer without getting things deleted; you just might have to put in a little effort that you probably should be putting in anyway to make your answer good for the canonical.
    – Cascabel
    Commented Apr 5, 2016 at 16:25

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