Currently these are our options for closing a question:
Every so often we get a question that isn't really a good fit for the site, only because there's information that we're not getting. This happens quite a bit with some of the medical questions, but also with some of the other questions. I've linked two that I remembered off the top of my head that I think would fit this close reason.
Currently, when we close these questions, we close them as either "unclear", or "too broad".
Unclear
This close reason doesn't really work in these cases because the question is clear. We know what they're asking, we're just missing some information that we would need before being able to answer the question. Closing these questions as unclear doesn't tell the user why we can't answer their question, it just makes them think that we don't understand them.
Too broad
This close reason fits better than "unclear", but I still don't think it really conveys what the problem is. It's not that there are too many answers, it's that without the information that's missing, we're just throwing out wild guesses.
I think that if we have a close reason for "Not Enough Information" then it will be more clear to users why their question is getting closed, leading them to edit their questions with the information, rather than going to someone else because they think we just don't understand their question.
Here's my suggestion for the close reason:
Not enough information
Please add more detailed information about the problem you are having and any steps you have already taken to try and resolve it. Currently, without the necessary information, answers to this question will be too vague or simply guesses.