survey bias

Currently collecting employment/working satisfaction data from survey at different countries. Same set of questions is used. I have come across that people from some countries tend to be more optimistic/pessimistic than others. How can I take their answering behaviour into consideration when...

Sorry if my seach of this forum failed to find a previous discussion of this issue. My simple understanding of surveys for which reponses are voluntary is that one cannot validly calculate things like bias, or validly adjust for any perceived bias, or determine a coefficient of variation for a...