Scale-sensitive response behavior!? Consequences of offering versus omitting a “don’t know” option and/or a middle category

The effect of a “don’t know” option (DK-O) and of a “middle category” (MC) on the survey response has been frequently examined. While researchers agree on some points, they disagree on how these options should be interpreted. For instance, a DK-O or MC may not necessarily be chosen due to a lack of a neutral/moderate opinion. This article addresses the consequences of offering versus omitting a MC or/and a DK-O. Data were collected by means of an online survey dealing with student participation (n=1,282). The results showed respondents who choose a DK-O may not have a neutral opinion. Conversely, respondents who choose a MC may not necessarily be undecided.