Ultimately, the question becomes how you will interpret the difference between no-answer and checking a particular box. If no answer by convention means “I don’t know the answer to this question,” then it makes sense to have a “I know the answer, but it’s none of the choices you give” box (aka “other”). It may also make sense to have a “I know the answer, but it’s more than one of the choices you give” box. Or a “I know the answer but don’t want to tell you” box. Etc.
Or, not. Much as people get annoyed by being asked to categorize themselves, that is basically the point of this sort of survey, and nobody is obligated to take it. There’s no particular reason you should change your strategy to alleviate our annoyance.
There’s also a validation issue. A blank could mean “I accidentally scrolled past this question without noticing it”. The standard for online surveys is to (where appropriate) include choices for “Other”, “None”, and “Prefer not to answer”, and then force a response for every question so that you know nothing was accidentally skipped.
That said, online surveys often fail at this, for instance having “gender” questions with just the 2 options (they should at least have an “other”) or only accepting as “valid” answers that do not fit the entire population (For example, a survey for doctors with no explicit age cutoff limited ages to <99; at the time, there was one practicing doctor older than that—he would just have been given an error message that his age was “invalid”.)
Ultimately, the question becomes how you will interpret the difference between no-answer and checking a particular box. If no answer by convention means “I don’t know the answer to this question,” then it makes sense to have a “I know the answer, but it’s none of the choices you give” box (aka “other”). It may also make sense to have a “I know the answer, but it’s more than one of the choices you give” box. Or a “I know the answer but don’t want to tell you” box. Etc.
Or, not. Much as people get annoyed by being asked to categorize themselves, that is basically the point of this sort of survey, and nobody is obligated to take it. There’s no particular reason you should change your strategy to alleviate our annoyance.
There’s also a validation issue. A blank could mean “I accidentally scrolled past this question without noticing it”. The standard for online surveys is to (where appropriate) include choices for “Other”, “None”, and “Prefer not to answer”, and then force a response for every question so that you know nothing was accidentally skipped.
That said, online surveys often fail at this, for instance having “gender” questions with just the 2 options (they should at least have an “other”) or only accepting as “valid” answers that do not fit the entire population (For example, a survey for doctors with no explicit age cutoff limited ages to <99; at the time, there was one practicing doctor older than that—he would just have been given an error message that his age was “invalid”.)