Impact of the Number of Scale Points on Data Characteristics and Respondents’ Evaluations: An Experimental Design Approach Using 5-Point and 7-Point Likert-type Scales

Abstract

A remarkable deal of social research is based on data collected through the use of Likerttype scales. The optimal number of response categories in Likert-type scales has been subject to an academic debate for years. This article studies the differences between 5-and 7-point Likert-type scales using the SERVPERF Scale, which was developed by Cronin and Taylor in 1992, as the measuring instrument. A pretest-posttest control group experimental design was used to test whether the differently pointed response categories lead to any statistical differences in data characteristics, dimensional structure of the scale and data fit. Results do not show any statistically significant differences in terms of normality and reliability whereas different dimensional structures are achieved for the 5-and 7-point scale formats of SERVPERF using Exploratory Factor Analysis. ANCOVA results reveal that the number of response categories is not affective on the participants' evaluations of SERVPERF. The results of confirmatory factor analysis show that the best fit is achieved for the 7-point SERVPERF. Keywords

Optimal Scale Points for Reliable Measurements: Exploring the Impact of Scale Point Variation

“…A further reduction to a five-point scale is troublesome and results in a relatively high level of inconsistency in the answer scores. Altuna and Arslan (2016) show that reliability increases with larger scale points, although the increase is insignificant. These authors conclude that the 5-point scale may be easier to apply and preferable.…”

Measurement of Humanity Among Health Professionals: Development and Validation of the Medical Humanity Scale Using the Delphi Method

“…This study was conducted to fill the gap by creating the MHS to measure the humanity aspect of health professional students, including integrity, respect, compassion, empathy, patient-centered care, giving, and altruism. A 7-point Likert scale was selected based on a study by Korkut Altuna and Arslan [ 17 ], which found no difference between 5-point and 7-point scales, and on previous studies that used a 7-point Likert scale [ 25 ]. The questionnaire was delivered electronically to students from various colleges and universities, including programs for medicine, dentistry, and pharmacy, using Google Forms.…”

“…The variables that were taken into consideration when the items were created to reduce incorrect result interpretation were clarity, simplicity, and orientation. A 7-point Likert scale was adopted (1=Strongly Disagree, 2=Disagree, 3=Slightly Disagree, 4=Undecided, 5=Slightly Agree, 6= Agree, and 7=Strongly Agree) [ 16 , 17 ]. Ten of the 27 items were inverse, meaning the Likert-scale ratings would be inverted, whereas 17 of the 27 were positive.…”

Number of Response Options, Reliability, Validity, and Potential Bias in the Use of the Likert Scale Education and Social Science Research: A Literature Review

“…The Likert scale with three response options also results in the loss of a lot of information, especially the intensity and strength of the respondent's opinion (attitude) (Çetin et al, 2020). They also reported that the highest Cronbach alpha coefficient (significant reached 0.96) was achieved on a response scale of 11 and a response scale of 7 with very small differences (James, 2019;Korkut Al Tuna & Arslan, 2016). While the lowest reliability is on the response scale 3.…”