Are Three-Point Scales Always Good Enough?

Abstract

Recent work by Jacoby and Mattell [6] has suggested that three-point Likert scales are sufficient to meet criteria of test-retest reliability, concurrent validity, and predictive validity. Green and Rao [3], using the criterion of data configuration recovery, concluded that sixor seven-point scales are preferable, and the authors are skeptical about the ability of large numbers of such scales (three- or two-point scales) to 'make up' for the limited information provided by each scale separately. In a reply to Green and Rao, Benson [1] argued that the frequent applicability and practical convenience of twoor three-point scales are strong points in their favor. Moreover, the focus of marketing research on population averages, rather than individuals, suggests that scales with few categories are adequate. This article delineates the conditions under which a two- or three-point scale may be good enough. BACKGROUND