THE MEANING OF I DONT KNOW IN OPINION SURVEYS - INDIFFERENCE VERSUS IGNORANCE

The purpose of this paper was to examine whether ''I don't know'' responses (DKs) in opinion surveys are best understood as expressions of ignorance or indifference. Intuition and literature review suggest that they are most likely an indication of ignorance. This understanding led to the formulation of two competing models which were tested. The results provided considerable evidence that DKs are more properly interpreted as expressions of ignorance rather than indifference and consequently should not be used as midpoints of continuous scales measuring opinions, attitudes, or beliefs. Failing to do so may well result in serious misunderstandings of questionnaire and interview responses.