Stuck in the middle: the use and interpretation of mid-points in items on questionnaires.

Likert-type scales are commonly used when assessing attitudes, personality characteristics, and other psychological variables. This study examined the effect of varying the number of response options on the same set of 28 attitudinal items. Participants answered items using either a 4-point scale (forced choice), a 5-point scale that included a "neither" mid-point, or a 4-point scale with an option of "no opinion" presented after the item.