I foresee a number of topics that will probably come up again and again on this site in the future. As one has already been asked, I think we may want to come up with a policy for these types of topics while we're still in beta.

The topic in question is 'how to determine the running time of an algorithm', asked here.

This is a very fundamental question to CS; it is one of the basic topis that comes up again and again. However, the question asked there is also very broad: a proper answer would be quite long, as it would essentially contain several lectures' worth of information.

I don't see any easy way of constraining the question such that it becomes answerable with a shorter answer - note that the question 'what is the running time of this algorithm' is a different kind of question, though very closely related: the first asks about techniques, the second about a single answer.

Another one will be 'how does big-oh notation work?', 'how can I write my own compiler?', and others I can't think of right now.

I see two ways to deal with these kinds of questions.

  1. Shoot them down on sight. Questions that are too broad like this will be closed (I think as 'not a real question', but I could be wrong). The reasoning would be 'these questions are too broad, you may be better off taking a course somewhere'.
  2. Have a single question with one (or more) big answers, giving a lot of information about the subject. Close all other questions that will pop up as duplicates of the first one, and hope that people visit the linked question and either get their answer there, or be provided with enough information to ask a directed, narrower question.

There are already plenty of example of type 2 Q&A pairs, such as this one and this one, but there are many more. Another good example is this one.

Which option is preferable? Is there an option 3? Am I predicting this completely wrong?

  • $\begingroup$ or something like this? $\endgroup$
    – Kaveh
    Mar 13, 2012 at 0:28
  • $\begingroup$ @Kaveh: yes, exactly like that. I saw something about tagging them as 'faq', which I have seen before when viewing questions, so maybe SE already has a mechanism for this :) $\endgroup$ Mar 13, 2012 at 0:32
  • $\begingroup$ You can always edit a good question into a more general one so it can serve as a canonical Q&A $\endgroup$
    – Ivo Flipse
    Mar 15, 2012 at 10:53

1 Answer 1


This kind of question and answer pair is known as a “canonical Q&A”. The subject has been discussed on the main Meta.

Generally, these questions arise after many similar questions have been posted. It is far better to write them with the benefit of experience. Without this benefit, it's very hard to aim for the right audience, for the right level of detail.

If a question arises naturally, it's a different matter. Take them as they come! What I don't recommend is to try to create such questions yourself.


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