<p>It's really up to you what you do with your answer.</p>

<p>I sometimes misread questions. </p>

<p>Once I realize, most of the time I improve my answer in light of the new understanding. Sometimes I see that the actual question is well answered already and if mine doesn't have anything to add, and still wouldn't add much after an edit, I might delete mine. Sometimes I write a note at the top of my answer explaining what's wrong with it and <em>then</em> delete it (higher rep users see all deleted answers, so that's not as pointless as it sounds). Sometimes I do other things. Occasionally, where I think it might be more informative to do so (e.g. where there's a particularly enlightening comment in response to it), I choose to leave it stay as is. [And occasionally, though I intended to do something, I just forget to do anything with it.]</p>

<p>If you can see value in the discussion under your question (I think there is value there, but it's really up to you), you might leave it. Or you might change your answer to improve it, or you might delete it. Any of those are potentially reasonable choices. I think a good criterion would be "what leaves this question being the most useful to later readers, who have a range of abilities?". </p>

<p>If the question is easy to misread it might in some cases be quite beneficial to later readers to leave the answer but make clear that it is based on that misreading (since if they also misread the question they might end up there looking for just that kind of answer). [On the other hand, it might then be reasonably argued that the question should be edited.]</p>

<p>On the whole I think that if the question really has only one interpretation, broadly speaking the answers that stay around should respond to it, but I would not want an overly-prescriptive rule on that because sometimes there's a good deal of value in the responses to/discussion of a mistake. </p>
