1
In which of these situations might a questionnaire be appropriate?
Yes, a questionnaire can be used to get anonymous feedback and can be used to identify minor side effects (nausea, mild rash, headaches etc).
It can be used to identify first symptoms associated with a condition (for example, thirst and diabetes). However, asking people by questionnaire their first symptoms might have a problem in that peoples recall or memory may not be perfectly accurate. So in this case it might be good to validate the answers with medical records.
Questionnaires can not be used for serious side effects (people might be dead or in hospital so can't fill out the questionnaire).