This feature request is a response to Anyone want to clean up some bad titles?

Two days ago, Björn suggested that we warn users when they post a new question with an identical title to an existing question. However, given that there are 10,881 question pairs with identical titles on Stack Overflow (hat tip M. Tibbits) as well as ...

... I suggest that we take it a step further.

Let's extend the heuristics for detecting—and blocking—low-quality questions to enforce unique titles, or at least flag new questions with duplicate titles automatically.

We can leave the precise heuristics of detecting a duplicate title up to the Stack Overflow development team. I have no delusions about the fact that a few questions will "slip through the cracks." The goal here is to be proactive about minimizing the number of duplicates, and I think that the best place to start is the existing heuristics for detecting low-quality questions.

After all, duplicate question titles are bad for a number of reasons: They often indicate a question that is itself a duplicate, but perhaps just as importantly, they decrease the signal-to-noise ratio when searching for questions. I honestly can't think of any reason that duplicate question titles are helpful, unless you are asking for a solution to the same problem in a different programming language. Even then, I think that it would be acceptable to rephrase the question to say "How do I do X in (insert programming language here)?"

Frédéric makes a good point about the potential problems with this solution:

I have a hunch that if we do that, people will find ways to circumvent it (changing case or punctuation, adding random spam), and we'll end up stuck in a an arms race.

We may get stuck in an arms race with some users, but I honestly think that many people new to Stack Overflow just don't understand the etiquette of asking questions here. If we could even convince people to rephrase their question more clearly 20% of the time, I think that it would be a tremendous boon to the community. Furthermore, remember that heuristics for low-quality questions already exist, arms race or no.

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    I have a hunch that if we do that, people will find ways to circumvent it (changing case or punctuation, adding random spam), and we'll end up stuck in an arms race. Sep 2, 2011 at 18:38
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    Better 2,456 duplicates than 10k.
    – user1228
    Sep 2, 2011 at 18:52
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    @Won't, well, I might be a little jaded lately because I use the 10k moderation tools more, but I do think the first reaction of most of the users who post that kind of question will be: Duplicate title? Sure, let me add a space there. Also, to them, further error popups (because someone else had the same idea) might be more frustrating than teaching. All in all, my pessimistic estimate would be nearer to a 25% decrease rather than your 75% :) Sep 2, 2011 at 19:01
  • I would be careful about title-dupe detection that doesn't take into account tags. "Where to learn about WMA features?" tagged with format would not mean the same as tagged with java-me
    – gnat
    Sep 2, 2011 at 19:16
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    @FrédéricHamidi: As I said before, "Users who do circumvent by this method are, therefore, less deserving of consideration when their titles stink. They have been notified of their failure, and yet they seek ways to continue to fail." Also, if something as simple as a space could defeat the heuristic used to determine duplicate titles, I'd suggest JA rethink his development hires (not that they'd be so naiive, of course).
    – user1228
    Sep 2, 2011 at 19:43
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    @gnat: Where is that question? I need to close it as "not constructive."
    – user1228
    Sep 2, 2011 at 19:44
  • @Won't, I did read that comment and you're right, but I was under the impression Chris's feature request was about improving question titles, not deconsiderating users (they already are in the current system, I mean, we all know them for what they are when we see them). Also, the heuristics having to take extra spaces into account is the start of the arms race I was referring to ;) Sep 2, 2011 at 19:51
  • @Won'tಠ_ಠ where is it? piece of cake. Find it flagged other, status declined, marked invalid
    – gnat
    Sep 2, 2011 at 20:46

4 Answers 4


As noted, the data shows that there's a good chance of duplication of titles, despite the existing UI that offers suggestions:

enter image description here

Basically, "we agree", so there will* be a strong check on adding new duplicates, including a link to (one of the) pre-existing questions (so you can go and see if that solves the problem), or (much more likely, IMO) suggest clarification of the title:

enter image description here

Since titles are often edited after the fact, this is also checked during edit:

enter image description here

You can of course work around this with trivial changes to the question, but anything that makes the user:

  1. consider whether a pre-existing question answers their question
  2. make the title more precise about their problem (rather than "C# problem")

is a good thing.

*=as usual, this refers to the next build; please don't rush off testing it right now...

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    This also kicks in when editing an existing question. I don't want to be forced to come up with a new title when I'm editing some grammar or formatting or something; I'd rather ask the OP to do that separately. Sep 27, 2011 at 17:25
  • @Tomalak if you didn't change the title, then that is a bug. Are you sure? If so, that will be fixed. Sep 27, 2011 at 17:28
  • I just went to double-check and actually I did remove a tag from the title. It's such an ingrained habit now that I didn't even notice doing it. :) Sorry. It's interesting though that, having added a dummy trailing "." to the new title for the time being, it was automatically stripped... and of course now the title is a duplicate title anyway. :) Sep 27, 2011 at 17:34
  • Does this apply to the actual title or to the ASCIIfied version of it that appears in URLs? If it applies to the latter, there will be problems on judaism.SE, japanese.SE, and perhaps others: on judaism.SE, for example, questions with titles "Why המוציא מחבירו עליו הראיה?" and "Why אין עונשין מן הדין?" are perfectly acceptable but have the same ASCIIfied title in their respective URLs.
    – msh210
    Sep 28, 2011 at 1:31
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    @msh210 no, it applies to the title as entered by a human; the url is unrelated to this test Sep 28, 2011 at 5:16
  • If you add a trailing space after the title, the duplicate check fails, even though the question's title's trailing whitespace is trimmed once submitted. Apr 10, 2014 at 18:45

I don't think this will help. What's wrong with my code? will just turn into What's wrong with this code?, What's wrong with my code, What's wrong with my Java?, and so on. Forcing unique titles is not the same as forcing good titles.

Obviously I agree with Frédéric in the comments above. Fewer dupe titles isn't a better situation unless the new titles are better. If they aren't fully changed to meaningful titles then you're only making crappy titles harder to find. Assuming users who post with bad titles will magically improve instead of doing the minimum to work around an obstacle requires more blind faith than I possess, personally.

In particular I don't think your example is any better. Tags take care of identifying the relevant language; putting it in the question title doesn't make it more informative.

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    Still, by forcing people to think about their titles for even a minute, I think that we could prevent many duplicates that are (unintentionally) posted by well-meaning users. Sep 2, 2011 at 18:48
  • Taking this to extremes: when trying to reuse the title of a closed question, close the new question right away too and block the account for some limited time! (More seriously: I don't understand why people answer questions like that.)
    – Arjan
    Sep 2, 2011 at 18:49
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    Users who do circumvent by this method are, therefore, less deserving of consideration when their titles stink. They have been notified of their failure, and yet they seek ways to continue to fail.
    – user1228
    Sep 2, 2011 at 18:54

When something like this is done, it needs a good UI.

My first idea would be to show the duplicate question, and say:

Could it be that you wanted to re-ask this question below?

If not, please select a title which clearly shows that your question is about something else than the question below.

This could be shown already when only the title is given, before one types the actual text.

On the other hand, in most cases of duplicate titles, both questions need to get better titles. So maybe simply silently (or after a warning) flagging both questions as "possible duplicate" or "bad title" for review could be actually more useful.

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    Start them off with one "Dupe" close vote by Community.
    – jscs
    Sep 4, 2011 at 18:37

Statistically, this is bound to fail, especially going to the point of completely disallowing duplicate titles. There are only so many words used in Programming and in questions in general, and with a few million questions, it will become a huge task to create a new title everytime you make a question or edit one.

It's ok to throw some ideas, and present the dupes in the list as shown in Marc's answer, but there needs to be some slack on actually being able to use duplicate titles.

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    There must logically be some difference between the questions - it follows then that briefly pointing to that difference in the title is possible, easy, and desirable. Sep 22, 2011 at 7:35
  • @Marc, I think trying to get the subtle differences that some questions will have into the title will just give us a lot of contrived convuluted titles. It will probably also increase the title length, which I'm always trying to keep as short as possible. Sep 22, 2011 at 13:59
  • If there are few million questions, then I suggest a large majority of them are duplicates. This isn't a support site for localised questions, remember. Sep 27, 2011 at 17:26
  • @Tomalak, You can have the same question title, and yet the tags will show them to be about different languages, as one example. They won't be dupes, but the algorithm of just checking on the title won't work well. Sep 27, 2011 at 17:35

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