Interpreting Likert type, summated, unidimensional, and attitudinal scales: I neither agree nor disagree, Likert or not

Abstract

This paper provides a rationale and convention for discussing the true limits and interpretation of data collected using unidimensional, summated, Likert-type, and attitudinal scales used in research investigating human behavior, sociology, education, psychology, and other related fields of study. All vague quantifiers must be described in methods and findings. The true limits of the scale and of each vague quantifier should be described. This information should be placed in the methods section. A five-point summated scale, for example, can be interpreted as follows: Strongly Agree = 5 - 4.51, Agree = 4.5 - 3.51, Neither Agree nor Disagree = 3.5 - 2.51, Disagree = 2.5 - 1.51, Strongly Disagree = 1.5 - 1. This paper also provides a rationale and convention for the use of nonstandardized effect size (ES) estimates to describe the magnitude and strength of the effect. This is accomplished by subtracting one summated M from another summated M and interpreted using the following convention: Small (ES = .19 and lower); Medium (ES = .20 - .49); and Large (ES = .50 and higher). The rationale for this is based on the intuitiveness of the measure, true limits of the scale, and scale intervals.

Keywords

• human behavioral research
• behavioral scaling
• educational research
• psychological research
• true limits
• effect size