I have a requirement where users are asking questions to patients in a clinical setting. The answers can be yes or no, or possibly a third option not applicable.
There are a series of such questions, and many people will be re-entering yes-no responses from a patient questionnaire, so I want to be careful to preserve the normal affordances with a yes or no question. Yet I need to ensure the not applicable option is there.
But "Not Applicable" isn't conceptually between yes and no in any respect, so that's likely to produce some mistakes.
Radios might be the "right" control for such an instance, but I want to preserve the obviousness of yes-no, so maybe the N/A option could be styled differently, and would disable the radios?
Of course, if we went ahead with this option, it'd need some design work. (The N/A options are too pronounced here).