Effects of Item Characteristics on Psychometric Properties of Forced Choice Scales

Abstract

Two studies examined the effects of indeterminate frequency modifiers, item length, and statement direction on response to forced choice scale items. A pilot study established relative intensities of nine adverbial modifiers. Study 1 ( N = 320) showed no effect on item variances due to the treatments. Differences were found between mean responses of short and long items as well as between positively and negatively stated items. Study 2 ( N = 110) investigated effects on scale reliability and validity related to different intensity levels of modifiers. It is concluded that differential responses to items may not reflect differences in the behavior referenced by the items but rather observed differences in individual responses may be due to the mechanical, grammatical or delimitive characteristics of the items.