Before closes as "unclear what you're asking", I'm asking the SE overlords and/or mods, is this is a fair summary?

Some comments on questions and one answer on the Meta discussion Can we be more careful in marking duplicates on questions that are related but ask for or about different things? seems to suggest certain users here are labouring under the mistaken belief that if two questions are different, but an older question's answer contains content that partially answers the newer question, that's grounds for closing as a duplicate.

It isn't. A duplicate means:

This question has been asked before and already has an answer

When is something a duplicate?

This has been discussed extensively on the main meta and official blog. Details below, but to summarise:

  • Closing as duplicate is for when the question is the same. The answers should match, too - but checking the answer matches is described by SE staff as a secondary "litmus test" after identifying that the question is the same:
    1. Is the question the same? If no, don't dupe, see below for alternatives.
    2. If yes, does the existing answer also answer this question? If no, reconsider question 1.
    3. If yes to both, dupe.
  • Canonical questions to general types of common problem are encouraged when there's one pattern that answers many slight variations on a question. Encyclopedic "massive canonical Topic FAQ" "tomes" covering entire topic areas are discouraged because they are too broad for SE, are bad for SEO, aren't user friendly, and because abuse "chokes out new information"

It really is about the questions, but checking answers is still important

SE staffer shog9 recently posted an answer for another SE site where people tended to dupe different questions that share an answer but were different questions:

...I would strongly recommend using answers as more of a litmus test than as a policy: if you're already pretty sure the questions are duplicates, testing the answers of one against the other can easily confirm your suspicions. But don't close completely irrelevant questions as duplicates of one another simply because there's an animated gif that happens to apply to both...

The simple solution when answers would be similar

If an older question's answer contains content that answers or partially answers a newer question that is not the same question or problem, the best approach is usually to post a short cross-linking answer like this:

You have a similar problem to people who do X. The advice on our question for them is:

[quote from conclusion]

This is based on [short quote or summary of gist]. Since you do Y, not X, you are different in that [...], but this advice still applies, because [reasons].

This way, people aren't left scratching their heads struggling to find the relevant bit when following the link, and if someone else knows more about this specific question than you (heaven forbid!), they're not prevented from posting a better answer that shares relevant detail that wouldn't be relevant to the (non)-dupe.

Sometimes, questions can be broadened so one canonical pattern can solve a range of questions...

From an older post from SE staff member shog9.

When you see a question that seems like it might reflect a common problem, don’t just answer it to get a few points. That doesn’t make the Internet any better. Instead, help us build up a library of canonical questions and answers that are more generic versions of the same question, and then start closing all the exact duplicates.


All that said, be careful not to go too crazy with this idea. The example you gave was a very poorly-asked question with a very simple (and common) problem - it's easy enough to find another question that covers the same problem. But some problems are not so simple, and it can be harder to find an existing question that covers the exact same issue.

In other words, when duping to a canonical general question, it still must address this exact issue, not simply be related background info. If it's relevant but not a match, do something else, like post a cross-linking answer with a short explanation (see below).

They must be based exactly on one common underlying problem or pattern

Shog9's first of several related reading links expands on this a little with a quote from an official blog post. The examples are very programming specific but it's not hard to see how they relate:

If you’re going to close a user’s question as a duplicate, it has to be a real duplicate. For example, if a user asks, “What does the IP address mean?” it’s OK to close that as a duplicate of a more general question like “What do IP addresses of the form a.b.c.d/e mean?” But it’s not OK to close it as a duplicate of a twenty-seven page guide to netmasks. That’s the moral equivalent of saying “RTFM.”

Stack Overflow is not meant to be a library of reference manuals. It’s supposed to contain the same information as a library of reference manuals, in the form of millions of questions and answers. Combined with Google, that gives us the magical power of a library of reference manuals you never have to read! It’s like, you got to the library, and there’s a wizard there at the door, and you ask your question, and, instead of being told to read a book, you just got (are you sitting down?) the actual answer!

They're not a tool to arbitrarily reduce the number of questions, throwing out nuance and depth: having "millions of questions and answers" is a good thing, so long as they reflect different problems (even subtly different problems). They're for cases where the underlying problem is exactly the same and is solved completely by one pattern.

They should be used with care and shouldn't get out of hand

That June 2016 Shog9 update to the policy over on the SciFi site (one of the few sites to also have aggressive dupe-closing of related questions) clarifies the drawbacks and limits of canonical questions:

The idea of a massive canonical Topic FAQ is persistently alluring; instead of having 50 questions about a "sorting hat", you could just have one question with a few dozen huge answers! However, this quickly becomes impractical:

  • Massively broad questions don't rank as well in search results as specific, focused questions.
  • Folks with specific, focused questions tend to not read massively broad FAQs even if they do find them.
  • Finding specific information among multiple answers to massively broad FAQs is troublesome.
  • Remembering which information is even contained in these tomes is difficult; eventually, folks just start to assume that they contain everything and close new questions without worrying whether they're actually answered or not... This chokes out new information.

There have been many, many, many cases highlighted on meta and in comments recently where aggressive dupe-closing "chokes out new information" relevant to a particular case, resulting in lower quality content.

It's right and proper to allow many variations between similar questions when those variations reflect real variation in the underlying real life problems reflected by the questions. This allows answers to have more nuance and higher quality. As a 2010 official blog post put it:

It's far more common to have many subtle variations of a question. I think that's OK, because that's how the world works. Trying to shoehorn a bunch of semi-related things into one arbitrary container in service of some Highlander-ish "there can be only one" rule is ultimately harmful. Remember: while there are aspects of wiki to our system, we are not Wikipedia. There is not one canonical question about every possible subject.

What if a new question isn't quite covered by a closely related existing canonical?

Bloating the canonical to fit a case that it's pattern or technique doesn't currently fit would clearly risk heading towards the massive canonical Topic FAQ tomes that are warned against. There's nothing awkward or wrong about having edge cases that are like a common canonical pattern, but with circumstances different enough that this doesn't solve them. Even the SE network's #1 ranked user Jon Skeet can have a question that is like a common canonical problem type but subtly, importantly different.

Let's use a recent example, where we have a great canonical resource on travelling with dual citizenship, and someone has a delicate problem where it'll be very difficult for them to do what the canonical answer suggests, where duping to the canonical question is like telling someone to read a (short, well-written) manual that doesn't actually even address the details of their specific problem.

shog9 gives two suggestions, and the second fits:

  • Post an answer that relates a different question to this one. I'm doing that right now (though with a blog post instead of a meta question as my source). Sometimes, it's hard for an asker to understand a solution presented elsewhere without something that relates the problem being solved there to the one they're having - a short answer that introduces, summarizes and then links to an answer elsewhere can provide the best of both worlds: a specific, focused answer to a semi-novel question and the refined knowledge of other members of the site, ranked and reviewed over the years.

...except of course in this specific example, the canonical doesn't contain the answer to their question, it only gives the background to why what they're trying to do is problematic, but you get the idea. Cross link, quote, explain why it relates, add missing details.

Example dummy answer

First, you should know that you shouldn't be travelling this way. [Here's our standard advice for similar cases](link to canonical).

Obviously it's too late to do this, since you've already booked tickets a different way, so you need to decide which is more important between rebooking your flights, or risking [x/y/z].

[add any further knowledge relevant to this case].

Even if you're only adding a little case-specific nuance beyond what the canonical says, this is better than closing, because someone could come along later who does has specific experience or professional knowledge of the asker's exact situation ("The authorities do X checks, and people get caught doing what you want to do all the time", or "You can safely do this because of A B C specific details, but only if you do X, Y and Z"), and they are not barred from offering a better answer. New information is not choked out.

To summarise:

  • duplicates should be the same question (and also check that answers match up as a "litmus test")
  • canonical questions and answers should be outlines of patterns that fit many cases (equivalent to “What do IP addresses of the form a.b.c.d/e mean?”), not user unfriendly, SEO unfriendly "massive canonical Topic FAQ" "tomes" stuffed full of every variant on a topic or theme.
  • 2
    Honestly, the best solution to the Chinese guy's question conundrum is to simply leave it closed and create a brand new canonical question about Chinese immigration schenanigans. This solves everyone's problem and follows the Stackexchange conventions.
    – JonathanReez Mod
    Commented Apr 26, 2016 at 13:37
  • 9
    Why is that better than answering someone's actual real life question? Commented Apr 26, 2016 at 13:43
  • 3
    Because that particular question is: a) Too specific (OP already has tickets and won't take no as an answer) b) Too broad (both about traveling with two passports in general and Chinese immigration c) Part of the broad question is already answered in a canonical question. We did the same with the flood of questions about traveling with electronics to India: created one canonical answer and closed the rest, even though there were dozens of truly different variations.
    – JonathanReez Mod
    Commented Apr 26, 2016 at 13:45
  • 5
    Too specific and too broad? That's got to be a first. Seriously, if someone visits our site who has experience or expertise with the Chinese system, which is too specific to add value to the general question, but would answer this guy's specific questions about APIS, why are we standing in their way? Commented Apr 26, 2016 at 14:07
  • 2
    It containts too many questions, one of which is too specific. We shouldn't stand in the way, but should create (or ask the OP to create) a separate proper question.
    – JonathanReez Mod
    Commented Apr 26, 2016 at 14:18
  • 6
    The "too localised" close reason was dropped years ago. If you're worried that the asker won't accept a good answer, a) that's speculation, b) that's their problem not ours, and not a reason to prevent knowledgeable people writing an answer that helps others who google something like "china USA dual citizen can apis check green card validity". Anyway, that other linked meta question is the place to discuss the details of that question Commented Apr 26, 2016 at 14:24
  • 2
    Someone has to be an annoying nitpicker so I'll do it. Technically, that guy is probably not a dual citizen, he lost his Chinese citizenship years ago and is still lying to the Chinese authorities about it. Interestingly, the original question steers well clear of this conundrum by talking about "using the Chinese passport", which is still perfectly accurate regardless of citizenship. Other than that a big +1 from me and I still don't have any foolproof solution…
    – Relaxed
    Commented Apr 26, 2016 at 18:17
  • 2
    As already discussed, there are more than 15,000 permutated variants of Schengen visa refusals. It is unreasonable to have that many questions in the archives before a duplicate could be marked.
    – Gayot Fow
    Commented Apr 26, 2016 at 18:27
  • related: meta.travel.stackexchange.com/questions/1525/… Commented May 2, 2016 at 7:17
  • I'm pretty sure that at least a few people who close these questions as duplicates are coming from Meta.SE, where the rules for closing as duplicate actually allow such closures.
    – gparyani
    Commented Mar 27, 2018 at 22:02

2 Answers 2


I truly agree with the OP! In fact I have just raised the question in chat if we should introduce an audit in reviews as I annoyingly found that new and unique questions get closed as duplicates of questions that do not have the answer to them. These questions would accumulate close votes (and be closed only to be re-opened) even after I pointed out in comments why the supposed duplicates did not answer the original questions.

Let me put one of these here as an example:

  • This Q asked about sleeping in a car / wild camping in Ireland and was marked duplicate to a Q about wild camping in Europe where only the third answer only mentions Ireland and only answered the wild camping part but not the sleeping in car one - anyone who read the Q however would be able to notice that this is not news to the OP: "On the UK mainland pitching a tent outside of a specified campsite is frowned upon but sleeping in a car you can usually get away with if you're away from main roads/angry farmers - is Ireland any different?"
  • 4
    Great example. Duping the "camping in Ireland" question doesn't just fail to answer the question, it prevents someone with lots of experience of camping in Ireland from sharing their experience in detail. Commented Apr 30, 2016 at 14:05
  • 3
    +1. I have experienced this myself, it is very off-putting for someone to spend an hour or more to research and ask a specific question, sometimes even linking to the canonicals concerned, and then have it instantly closed-off to answerers by a few overzealous mods (looking at @GayotFow in my case) thus preventing actual travellers from answering the specifics of the question. There could be a forced period of two weeks before questions can be closed as duplicates.
    – user29097
    Commented Jun 1, 2016 at 8:15

My opinion on this is different. Let's say we have a canonical question about "Peanuts on airplanes", which covers:

  1. What peanuts are
  2. What airlines serve peanuts
  3. Why other airlines don't serve peanuts
  4. Pros and cons of eating peanuts on board
  5. Link to a site listing if a particular flight serves peanuts

Now let's say someone comes in on the site and asks about "Chocolate peanuts on US Airways". We now have the following options:

  • Mark as duplicate and close
  • Answer the question
  • Expand the original peanuts question to include info on chocolate variations and US Airways
  • Create a canonical question about food on US Airways (with a section on peanuts)

I think we should always strive for options three and four, rather than try and answer every single peculiarity. The electronics in India question is a perfect example: while it doesn't cover 100% of the possible issues, it's still much better to have a centralized canonical question rather than 50 individual queries.

A second issue with having too many localized questions is up-to-dateness. Imagine if IATA bans peanuts on-board all airplanes tomorrow (which partially happened with batteries, for example). Going through dozens of individual questions is a lot harder than editing just a few canonical ones.

A third issue is being stuck answering highly localized queries. While the "too local" close reason was removed a long time ago, I believe there's still an expectation that questions must be useful to more than a few people in a highly specific situation.

  • 2
    +1, I like the part about expanding the original question to include more stuff. The OP can get upset (see meta.travel.stackexchange.com/questions/3612/…) but it is still better to have a broadly accessible canonical. Everybody in the world thinks they have a unique question, but it's not always the case.
    – Gayot Fow
    Commented Apr 26, 2016 at 18:41
  • 6
    I don't disagree with any of this for clear-cut "What are the rules on X" questions. However we see a lot of overzealous close voting of less clear cut questions, equivalent to closing (random example) "I have a very sensitive peanut allergy, how can I stay safe on a plane while causing minimum inconvenience to other passengers" because paragraph six of the canonical mentions that some airlines will announce to not eat peanuts if a severe allergy sufferer makes themselves known. It's relevant, and worth linking to, but duping misses every other element to and possible answer to the question Commented Apr 26, 2016 at 19:34
  • 2
    (there also seems to be a trend pushing back against questions that revolve around actual travel experience and aren't "please look up the rules on X for me", but that's a separate question!) Commented Apr 26, 2016 at 19:37
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    @user568458 A Nigerian applies to the Italian consulate with a forged passport. An Egyptian applies to the French consulate with a forged passport. An Indian applies to the German consulate with a forged passport. And these are all unique questions?
    – Gayot Fow
    Commented Apr 26, 2016 at 20:51
  • 4
    @GayotFow That's probably a clear cut case where there is an equivalent of “What do IP addresses of the form a.b.c.d/e mean?”. Just don't get overzealous with it if something's different but related (e.g. extending a visa that's genuine but contains an administrative mistake and therefore isn't recognised as genuine) Commented Apr 26, 2016 at 21:14
  • 4
    @user568458 I pretty much agree with this. If you add the UK and Schengen together, you have a grand total of about 26 refusal reasons but 294 countries and 26+1 issuing nations. I have it in mind that most of them are duplicates at the core essence. There are not enough refusal reasons to treat every question as unique because the OP is male vs female or Egyptian vs Nigerian or Germany vs France.
    – Gayot Fow
    Commented Apr 27, 2016 at 1:55
  • 1
    I don't think the example you have in this A is fitting, however the one by @GayotFow is. But that is not the point here, as the OP is clear to point out, we are talking about Qs that are not answered by a canonical, where answering in the canonical would make these to broad. E.g. like having a canonical "My visa has been refused, why, what should I do and what are the consequences?" for all nations, that is what the peanut example above is.
    – mts
    Commented Apr 30, 2016 at 15:12
  • 2
    Thinking about it, this seems beside the point. If you don't like the scope of a question, you can write your own close reason indicating why you think it's too narrow. And everybody is certainly welcome to create other questions along the lines of option 3 and 4 as you suggest. Meanwhile, a duplicate is a duplicate is a duplicate, we should not be abusing that system for questions that are simply not the same (especially when we have seen how error-prone this process is).
    – Relaxed
    Commented May 9, 2016 at 13:05
  • 2
    Please see latest update. SE staff have clarified where the line is between good canonical questions and bad "massive canonical Topic FAQ" "tomes". Some of what you describe is on the good side, but a lot of actual practice is clearly on the bad side. Commented Jul 12, 2016 at 15:30
  • @pnuts That's news to me and seems unnecessarily confusing. How are newcomers supposed to learn how to ask good questions and generally appreciate the site, if every time they fix a question it gets closed again with another, barely understandable reason? Meanwhile, there is a lot of evidence that the authoritative view on SO is that duplicates are only duplicates when the question is the same (not a vaguely related question and especially not a different question with an answer that would be helpful, it has to be the same question).
    – Relaxed
    Commented Oct 17, 2016 at 6:14
  • 1
    @pnuts Well, that's a slightly different point IMO. That a mod could not be bothered to reopen a question to fix that mistake does not mean that it wasn't a mistake or that we should do it in the first place! I.e. the implication is that if a wrong close reason was used, it's not serious enough to go to the trouble of opening and closing again (although I have done that!), not that we should use any close reason we damn please without taking care that it does apply to the question. That's a tendency I see all too often and I have the feeling the present answer is making excuses for that.
    – Relaxed
    Commented Oct 17, 2016 at 6:37

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