Including deleted questions, the current breakdown for questions asked and closed on Dec. 9, 2013 (the period jmac used) is:
- off-topic: 427
- unclear what you're asking: 139
- duplicate: 75
- too broad: 52
- primarily opinion-based: 33
Note that these numbers fluctuate as more questions are closed or reopened in the days and years ahead. Currently there are 99 duplicate questions asked on that day. So let's take a day from a few months ago so that the close activity is more settled.
Wednesday, October 9, 2013:
* questions asked: 9848 100%
* questions deleted: 1412 14%
* questions closed: 838 9% 100%
* off-topic: 516 5% 62%
* unclear what you're asking: 163 2% 19%
* duplicate: 110 1% 13%
* too broad: 42 <1% 5%
* primarily opinion-based: 30 <1% 4%
Note that the close reasons don't add up because questions are somethings closed and reopened again (and occasionally closed a second time). There are 861 close question events or 23 more than the current number of still-closed questions.
It's also important to note that since June 25, 2013 closure statistics are going to look somewhat different than before that date. In particular, the custom off-topic reasons were introduced on that day.
Finally, while I think this is a representative sample, it's only one day. If I'd picked a different day, the results would be different.
Here are the custom off-topic reasons that were picked for closed questions asked on 2013-10-09:
- 267—Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results. See also: Stack Overflow question checklist
- 75—Questions concerning problems with code you've written must describe the specific problem — and include valid code to reproduce it — in the question itself. See SSCCE.org for guidance.
- 72—Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it.
- 42—Questions about general computing hardware and software are off-topic for Stack Overflow unless they directly involve tools used primarily for programming. You may be able to get help on Super User.
- 26—Other (add a comment explaining what is wrong)
- 17—Questions on professional server, networking, or related infrastructure administration are off-topic for Stack Overflow unless they directly involve programming or programming tools. You may be able to get help on Server Fault.
- 17—This question belongs on another site in the Stack Exchange network