Choosing response categories for summated rating scales.

Abstract

One of the many decisions or judgments that is required in the construction of summated rating (Likert) scales is the selection of response categories. This selection is often made on no more solid basis than habit, imitation, or subjective judgment. Yet the equal interval properties of the response continuum is assumed even though this assumption may, in fact, be false. Respondents to summated rating scales may treat the response choices as if they are equally spaced along the psychological continuum, but personal experience has taught that they also may not. When faced with a scale of unequal intervals, subjects sometimes complain of a difficulty in making responses because some adjacent choices are closer together than others. To eliminate this problem, equal interval response categories should be used. The current study was an attempt to derive scale values for three sets of commonly used response categories. That such words and word combinations can be meaningfully scaled has been shown by Jones and Thurstone (19SS), and the consistency of the scale values for adjective-adverb combinations has been demonstrated by Cliff (1959).