I designed a questionnaire for surveying community satisfaction. But many participants have chosen “don’t know” in answers. Some even have ticked “don’t know” answers for most of the questions. How could that be?

It’s my pleasure.

Many thanks for your explanations.

Great that you ask this question. “Don’t know” answers do not always imply the participants “don’t know.” Too complicated questions or too long explanations will both reduce the participants' intention to think carefully about their situations, thus choosing “don’t know.”