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

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.