I am just wondering, should all the questions which are used in the qualitative observational survey (i.e. KAP studies) needs to be validated and check for their reliability all the time?
I know, if a survey includes the usage of a specific questionnaire, then it has to be validated and checked for its reliability ( like Cronbach's alpha). But what about cross-sectional surveys which just deals with very few questions related to some specific topic like only beliefs or opinions etc.