UX questionnaire

The standard satisfaction questionnaire is one type of UX questionnaire. UX questionnaires are a family of questionnaires. People often refer to validated questionnaires (i.e. confirmed through a scientific process). There's a whole range of validated questionnaires in UX, each one focusing in particular on certain aspects of the user experience.

If we're talking about a validated questionnaire, AttrakDiff for example, you absolutely have to use every item it contains. Otherwise the conditions for validity aren't met. If you build a questionnaire yourself, you're generally looking for a trade-off between completion time (the effort the user puts into filling it in) and the level of detail you ask about (your goals with the questionnaire). You can have a very short questionnaire with a single question, just as you can have a very thorough one with questions asked depending on the answers to other questions and which takes several dozen minutes to fill in.

Writing a good questionnaire is a complex exercise. The wording of the questions, the format in which the user can answer and the order in which the answer options are presented are the main biases to watch out for. Validated questionnaires have the advantage of a safe framework: a standard collection format, the wording provided, and a set procedure for analysing and interpreting the results, also provided.

The UX questionnaire belongs to the family of quantitative methods. The user interview is one of the qualitative methods. By their very nature, the two methods don't let you address the same subjects. The only thing the two have in common would be an open question you're asked to answer. In a questionnaire that is filled in independently, you keep the number of those down and leave them optional.

Yes. Several validated UX questionnaires focus in particular on usability. The variants that exist adapt to the type of system being assessed (a professional tool, a consumer service). The System Usability Scale (SUS) is the most widespread, with ten questions rated on a scale of 1 to 5. The SUS produces a score you can compare with other benchmarks. If the score is above 68, you can conclude that the usability of the service tested is above average. A questionnaire like the SUS gives you an overall value. That doesn't replace user testing, which lets you understand more precisely the low scores given by some users.