====== Multiple Choice ======

With a multiple choice you can select none, one or more answers. By default, browsers display the input fields differently (square under Windows) than with simple selection questions (round under Windows).

The data structure (variables) looks significantly different with a multiple selection than with a normal selection question. While a normal selection question has only a single variable, the multiple choice question has one variable per selection option. Because each selection option can be selected (code 2) or not selected (code 1).

===== Missing Answers =====

In a multiple choice question the participant can __not__ give no answer. If you set a checkmark, this means "yes", if you do not set a checkmark, this means "no". Because of this there is no logical difference, if an answer was given or if the item was skipped.

However, each multiple selection has an additional variable that specifies the number of selected options (positive code or 0) or the code of the alternative response (negative code).