Likert Scale

Likert Scale

A Likert scale is a commonly used psychometric response scale to measure participant’s attitudes and/or degree of agreement with a given question or statement. Most commonly seen as a 5-point scale ranging from “Strongly Disagree” on one end to “Strongly Agree” on the other, with “Neither Agree nor Disagree” in the middle. Sometimes a 4-point (or other even-numbered) scale is used; this is called a “forced choice” method as the neutral option (Neither Agree nor Disagree) is not available.

Please indicate how much you agree or disagree with the following statement:
Statement Strongly Disagree  Disagree Neither agree nor disagree Agree Strongly Agree

I like to learn about

new things

(1) (2) (3) (4) (5)

A Likert scale falls within the ordinal level of measurement because we cannot presume that participants perceive the difference between adjacent levels to be equal. However, it has become common practice to treat Likert scale response data as if it were interval data. A number of different analysis methods can be applied depending on how the questions are treated.

When individual responses are treated as ordinal-level scales:

  • Employ median and mode as the measure of central tendency
  • Summarize variability by range and inter-quartile range
  • Analyze data using non-parametric statistical tests
    • Mann-Whitney U test
    • Spearman’s Rho
    • Kruskal-Wallis test

When multiple responses are summed together and treated as interval scales (on the conditions that all statements use the same Likert scale, the subscale was collected using a 5-7 point Likert response format with no resulting bias, the assumptions are clearly stated, and the data is of the appropriate size and shape):

  • Analyze data using parametric statistical tests
    • Analysis of Variance (ANOVA)
    • Regression

Read more about the myths of “Likert Scale” from:

Carifio, J., & Perla, R. J. (2007). Ten common misunderstandings, misconceptions, persistent myths and urban legends about Likert scales and Likert response formats and their antidotes. Journal of Social Sciences, 3(3), 106. [PDF] from thescipub.com

Norman, G. (2010). Likert scales, levels of measurement and the “laws” of statistics. Advances in health sciences education, 15(5), 625-632. [Full Text] from springer.com

Preston, C. C., & Colman, A. M. (2000). Optimal number of response categories in rating scales: Reliability, validity, discriminating power, and respondent preferences. Acta Psychologica, 104(1), 1-15. [PDF] from rangevoting.org

 

  

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