Usability for Nerds/Surveys, Questionnaires, Forms and Option lists
Software often has a dialog box asking for user information. Web shops often have a form asking customers for personal information. Online surveys as well as telephone polls ask respondents about their personal information as well as their opinions. It is a common characteristic of dialog boxes, forms, surveys and polls that they mostly have a limited range of predefined answer options.
Online questionnaires are cheap and easy to make, perhaps too easy. If the company or organization that set up a questionnaire had to pay all the respondents a standard wage for the time they spent on answering the questions, perhaps they would put more effort into planning the survey, making pilot studies, and analyzing the answers more thoroughly than just a simple statistical summing of answers. A predefined list of answer options is easy to analyze statistically, but the results are not always useful. The most useful answers are the ones that you didn't think about when you made the list of answer options. If you want to find problems in a product you are selling, you can only make answer options for the problems you are already aware of. A predefined list of answers cannot reveal new problems that you were not already aware of. It is not very helpful to know that 15% of your customers are dissatisfied if you don't know why they are dissatisfied.
Therefore, there should always be an open category or a comment field where the respondent can write a comment about why none of the predefined answers is appropriate or why the question is completely off the point to the problem or opinion that the respondent has. All questionnaires should have open fields for commentary. Such comments cannot be analyzed automatically by a computer, but a questionnaire with only predefined answer options is of very little value anyway. If you are not prepared to spend time on reading comments then you should not let your customers or respondents spend time on filling out a questionnaire. It is a sign of disrespect to let people spend time on a survey or questionnaire if the result is not useful anyway.
No matter how many possible answers you list for questions about race or religion or other personal characteristics, there will always be somebody who don't feel that they fit into any of your categories. If you thought that sex can only be male or female - think again. There are transgender or intersex people who feel offended by the binary definition of gender. Facebook has been among the first companies to take the consequence of this and allow a lot of different gender categories that you didn't even know existed.
Don't ask questions about sensitive or private information unless it is necessary to the purpose of the questionnaire. People may feel that questions about their race, religion, political stance, income, sex or marital status are invasions of their privacy. At the very least there should always be an option to not answer a question.
The purpose of a questionnaire should always be clear to the respondent. People feel frustrated if they find out that their answers are used for a different purpose than they expected.
You may make it interesting or rewarding to answer the questions in order to motivate the respondents. It is rewarding to be allowed to voice one's opinion or complain about a problem - It is boring to answer questions about how many times you have bought a particular product last year. But respondents get disappointed if their answer is not used. If a customer complains about a problem then they deserve an answer with a possible solution.
A few bad examples will illustrate the points:
Interviewer: How do you like country X on a scale from 1 to 5? Respondent: What do you mean? X as a tourist destination? It's geography? It's people? It's industry? It's political system? The interviewer repeats the question. Respondent: That doesn't help. Interviewer: I am only allowed to repeat the question, not to interpret it. Respondent: Then I don't understand the question. The interviewer has no category for "question not understood", so he checks the answer "don't know".
A customer uses an online support chat system to get help with a technical product. The support lady says that the feature that the customer expects is not available. Afterwards, the customer gets a feedback questionnaire asking him to rate the quality of the support he has just received. He rates it as bad, expecting to get a chance to explain why. But the questionnaire just says thank you for your feedback. The customer now finds out that the only thing this questionnaire is used for is to pay the support staff after performance. He feels sorry for taking money from the hard-working support lady when the problem is not her fault, but there is no way he can undo his answer.