The Optimal Number of Response Alternatives for a Scale: A Review

Abstract

A conceptual framework employing the distinction between stimulus-centered and subject-centered scales is presented as a basis for reviewing 80 years of literature on the optimal number of response alternatives for a scale. Concepts and research from information theory and the absolute judgment paradigm of psychophysics are used. The author reviews the major factors influencing the quality of scaled information, points out areas in particular need of additional research, and makes some recommendations for the applied researcher.