A Comparison of Psychometric Properties and Normality in 4-, 5-, 6-, and 11-Point Likert Scales

Abstract

The Likert scale is very popular, but the question as to the number of scale points is still controversial. This article studies the differences among 4-, 5-, 6-, and 11-point Likert scales with a sample of 1,217 students in Macau, using the Rosenberg Self-Esteem Scale as the measuring instrument. There is no major difference in internal structure in terms of means, standard deviations, item–item correlations, item–total correlations, Cronbach's alpha, or factor loadings. Findings indicate that having more scale points seems to reduce skewness, and the 11-point scale, ranging from 0 to 10, has the smallest kurtosis and is closest to normal. Only the 6- and 11-point scales follow normal distributions from Kolmogorov–Smirnov and Shapiro–Wilk statistics. Results on predictive validity are inconclusive. This article discusses future applications and suggests the use of an 11-point scale as it increases sensitivity and is closer to interval level of scaling and normality. Recommendations for social workers and teachers are made to better assist when using self-reported measurement scales.