There have been several discussions on meta about how to organize frequently asked questions, and one idea is that one can simply write and answer such a question, creating a thread that can later be used to close duplicates:

Good approximations to FAQs are possible by someone just writing a good question and then answering it really well. (@NickCox in Does it make a sense to create the reference questions for popular topics?)

When I have time in a couple of weeks I'll start a controversial one to see how the process works, e.g. FAQ: How do you interpret a large P-value? (@FrankHarrell in Common Issues and FAQs)

I think nobody attempted it so far. While reviewing PCA questions, I noticed that technical questions about the relationship between SVD and PCA are asked every now and then (example: Why are the singular values of a standardized data matrix not equal to the eigenvalues of its correlation matrix?; more examples: two, three, four, etc.), but there is no one thread that is good enough to be "canonical". The only pretty good thread is on math.SE and we cannot use it for closing duplicates here.

So I decided to try it out, by writing and answering a question myself:

Do you think it makes sense? Or is it a waste of time?


1 Answer 1


one idea is that one can simply write and answer such a question

Indeed, the Stack Exchange model clearly allows for this strategy; you're explicitly allowed to write-and-answer your own questions. If they're useful to others, it doesn't particularly matter why you want to do it. There are already checks in place to avoid abuses of this approach (not that I expect any).

I've used the answer-your-own-question strategy myself -- really wanting a good discussion of interpolation that I could point to in answering other questions (it cropped up as an issue in a bunch of posts over the course of a couple of months at one stage), I wrote and answered one on interpolation in statistical tables. In those other questions where I wanted to mention interpolation in my answer, doing justice to the issues would lead to long answers that were distracted by side issues. It's so handy to be able to include a sentence like "On the other hand, if you're working from tables, you can just use interpolation." as part of a discussion of some other issue. That way if the reader doesn't know about it (and I seem to encounter so many people these days who aren't familiar with even the basics) they can at least get some decent coverage at the link (without worrying about link-rot), and I can proceed on the basis that the content of the post is already available, without bothering the significant number of people for which the single sentence mentioning interpolation is sufficient.

As I've come to refer to that question later, I have improved on the original answer I posted a couple of times, though it still lacks an entire subsection I'd like to include.

As a general principle, I think it (answering a tailor-made question to address a specific issue that you want to have a canonical answer on) is an excellent strategy for particular situations.

Such answer-your-own-question exposition on some specific issue style posts are very rare here, so I don't think there's any substantive danger in doing so when you feel the need. The usual mechanisms for encouraging good posts, discouraging bad ones and removing superfluous ones will still function as they should.

Indeed, I'd love to see a few subject matter experts do one or two such posts -- I imagine Xi'an or Dianne Cook or rvl or Rob Hyndman (to name a few such reasonably active experts, hopefully without offending a substantially larger number of other experts that I have not also mentioned for any good reason) could write some great answers to questions that haven't yet been asked in just the right way as to invite a really good exposition on some specific issue within their area of knowledge.

The main downside risk I see is that such questions might be mostly ignored, but the cost is relatively low so it's hardly a great issue.

On the up-side, a very well-written question (and I think my example above perhaps fails on that score) will likely invite other answers. Indeed, the back-and-forth between knowledgeable people in discussing some issues on other questions has in some cases been even more valuable (at least to me) than the answers.

[Indeed, in some circumstances, we could also simply post good questions and see if a comprehensive answer of one's own even proved necessary -- look at some of Jeromy Anglim's questions, for example; he frequently posts questions I am certain he could write quite a good answer to. So that's another arrow in the quiver.]

In short, I think you should simply go ahead and do it where you think it's needed, and not worry about it. You're surely able to judge when the right question for the answer you need to write doesn't yet exist.


Actually, I don't even think the opening paragraph on your question is really required, nor even to identify it as a FAQ (unless people tend to use searches containing 'FAQ', in which case it's potentially quite helpful to keep it).

Either it's a good question or it isn't. Either it's a good answer or it isn't. So if it's a useful question and a useful answer, there's no problem, and no issue (and votes will - albeit noisily - signal opinion on the value). On the other hand, if it isn't useful the system that's in place is designed to deal with that too.

There's simply no reason to hold back from doing what you think will help.

  • $\begingroup$ Thanks a lot, Glen, for such a thorough answer! The opening paragraph in my question is of course to be removed later; I inserted it, as well as created this meta thread, in order to to draw some attention to this topic and perhaps to motivate some much more knowledgeable people than me to post such Q&A threads as well... I fully agree with you that it could be very interesting if people did it more often. $\endgroup$
    – amoeba
    Jan 21, 2015 at 10:03
  • $\begingroup$ Perhaps you are right and the word "FAQ" should better be removed from the title. But I am not sure... Would be curious to hear what other people think. In this particular case my question and answer are very very basic and standard, and don't contain any sophisticated or non-trivial material. $\endgroup$
    – amoeba
    Jan 21, 2015 at 10:05
  • $\begingroup$ Also, thanks for the link to your interpolation question. I have seen it before (and upvoted back then) but forgot that it was a Q&A question as well. By the way, it would be interesting to use the data site to search the CV for all questions posted simultaneously with the answers. My knowledge of SQL commands is a bit rusty, so if somebody else could easily provide a corresponding request I would be most grateful. $\endgroup$
    – amoeba
    Jan 21, 2015 at 10:06
  • 3
    $\begingroup$ I think this answer summarises the situation excellently and that you, @amoeba, have done a very good job. I'd just advise strongly against the flag "FAQ". If it's noticed, then people might start using it capriciously or for not so good reasons, which we don't want; or then we have to start identifying criteria for when it fits, which (I suggest) we don't want; it's too hard! If it's not noticed, it serves no purpose. In short, wanting to do this and doing it are both excellent, but it's a matter of filling a gap, and whether we do that on purpose or not is a matter of personal motive. $\endgroup$
    – Nick Cox
    Jan 21, 2015 at 11:00
  • $\begingroup$ Thanks, @Nick. You convinced me about avoiding "FAQ" in the title; I edited the question to remove it. $\endgroup$
    – amoeba
    Jan 21, 2015 at 16:29
  • 1
    $\begingroup$ Follow-up to my comment #3. Here is a query I wrote to find all (currently 17) questions posted simultaneously with the answers: data.stackexchange.com/stats/query/266804. $\endgroup$
    – amoeba
    Jan 21, 2015 at 16:34
  • $\begingroup$ @amoeba interesting. Some good ones there. There may be some where the question and answer are not posted on the same day. There are over 1600 self-answered questions though, so I don't plan to go through them all to pull out the others that seem to have been designed to be answered by the OP (though I have found some answered later where I believe the OP likely had their answer in mind when posting). $\endgroup$
    – Glen_b
    Jan 21, 2015 at 22:30

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