Don't Knows (DKs)

"Don't Know" responses (DKs) occur when respondents report that they do not know or are uncertain about the answer to a survey question, whether it be about their behavior, attitudes, beliefs, perceptions, or a factual question. Don't Knows are often considered to be nonsubstantive responses and a form of item non-response. A high level of DKs is sometimes used as an indicator of poor data quality. DKs also create problems for statistical analysis. Researchers often treat DKs as missing data and often exclude cases in which respondents said "Don't know" from their analyses.

Respondents may say they don't know in response to a survey question for a number of reasons. They may genuinely not have an opinion or belief to report. Alternatively, satisficing theory suggests that ...