According to this article from Ben Butina on the eLearning Industry site, “How Many Options Should A Multiple-Choice Question Have?“, the answer is 3.

Coming from a site targeting industry trainers it’s tempting to write this off as a staff time saving measure for mandatory online courses, but a quick check of the attached links shows it’s pretty legit.

I would like to know if the approach to the questions changes the result. The standard format usually starts with 1 obviously wrong and 1 obviously right. But what about the other options – are they also clearly wrong, or do they tap into common misconceptions/mistakes? Does that have an impact?
I also wonder if it applies to one of my favourite MCQ approaches. Every answer is wrong and the student has to pick the least damaging option (although to be fair I mainly use it in branching scenarios rather than simple MCQs)

But, based on this I’ll probably shift to using 3 options most of the time. If I’m dealing with a subject that has numerous areas of common misunderstanding I’ll probably use more.

Here’s a quote straight from the article

“Three-option questions are just as reliable and valid as four- or five-option questions. (In fact, some evidence suggests that three-option questions are more reliable and valid than four- or five-option questions.)

Three-option questions do not reduce the difficulty of a test compared to four- or five-option questions.

Scores for tests made up of three-option questions do not differ significantly from tests made up of four- or five-option questions.

Students can complete three-option questions more quickly than four- or five-option questions.”