When you want to use a question for your statistical survey, you have to design also what kind of answer you will collect.

Among the choices you have are:

• binary answers: yes/no ,  agree/disagree ...
• a scale: "on a scale from 1 to 5, where 1 is "I strongly agree" and 5 is "I strongly disagree" ...
• a list of classes: interval of values (useful when you're askong about a time)
• a list of options, among which only one is to be chosen
• a list of options, among which more than one can be chosen
• a completely free answer

Completely free answers may take some time to write down, and some time to analyse afterwards: you may have to decide to create categories to analyse everything you got.

Nevertheless they can be very interesting as they may introduce new ideas you did not have beforehand.