“Don’t Know” Means “Don’t Know”: DK Responses and the Public’s Level of Political Knowledge

Does the public know much more about politics than conventionally thought? A number of studies have recently argued, on various grounds, that the “don’t know” (DK) and incorrect responses to traditionally designed and scored survey knowledge items conceal a good deal of knowledge. This paper examines these claims, focusing on the prominent and influential argument that discouraging DKs would reveal a substantially more knowledgeable public. Using two experimental surveys with national random samples, we show that discouraging DKs does little to affect our picture of how much the public knows about politics. For closed-ended items, the increase in correct responses is large but mainly illusory. For open-ended items, it is genuine but minor. We close by examining the other recent evidence for a substantially more knowledgeable public, showing that it too holds little water.