The use of don't know answers in communication research

This study has presented an investigation into the effects of a Don't Know (DK) option on a survey upon substantive response rates. The data suggest that not offering a DK choice on a Likert-type closed question survey does not reduce the substantive response rates of participants. Subjects were collegiate students at a mid-size Midwestern university enrolled in an introductory public speaking course during a summer session, with half being offered a DK option and the other half not. Application of ordinal data, significance testing, and content analysis of the questions reveal that denying a respondent the opportunity to express a nonopinion does not automatically result in an omission of a response.