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Adding Moderately or Somewhat to Agree and Disagree

Although the 5-point Likert scale is an ordinal scale, it has been widely used as an interval scale. If it is frequently used as an internal scale, is there a way to design the five options of the Likert scale (Strongly Disagree, Disagree, Neutral, Agree, Strongly Agree) to make them become close to equal intervals? What if we add an adjective “Moderately” or “Somewhat” to the Agree and Disagree options? Would it generate more interval-like data?

After my graduate assistant, Douglas Hutchinson, worked in my WORC research lab for a year and participated in a couple of my ‘Evidence-Based Survey Design’ research projects, he decided to lead this research question as his thesis topic with Dr. Chyung as his thesis advisor, answering the following research questions:

  1. Does adding an adverb (such as Moderately, Slightly, and Somewhat) to Disagree and Agree in the 5-point Likert scale influence people to perceive the scale to be closer to an interval scale, when administered in a web-based environment?
  2. Does the order of response options in the Likert scale (ascending vs. descending) make a difference in people’s perceptions as tested in Research Question #1?

The research results showed:

  • Using Moderately Disagree and Moderately Agree made the 5-point Likert scale close to an interval scale, respectively, regardless of the response orders used. That is,
      • Strongly Disagree, Moderately Disagree, Neutral, Moderately Agree, Strongly Agree (close to interval)
      • Strongly Agree, Moderately Agree, Neutral, Moderately Disagree, Strongly Disagree (close to interval)
  • Adding other adverbs Somewhat and Slightly to Agree and Disagree made the 5-point Likert scales to be clearly ordinal scales in both response orders used.
      • Strongly Disagree, Somewhat Disagree, Neutral, Somewhat Agree, Strongly Agree (ordinal)
      • Strongly Agree, Somewhat Agree, Neutral, Somewhat Disagree, Strongly Disagree (ordinal)
      • Strongly Disagree, Slightly Disagree, Neutral, Slightly Agree, Strongly Agree (ordinal)
      • Strongly Agree, Slightly Agree, Neutral, Slightly Disagree, Strongly Disagree (ordinal)
  • Adding Somewhat to Agree and Disagree without including the midpoint, Neutral, in descending order made the 4-point Likert scale close to an interval scale. That is,
      • Strongly Agree, Somewhat Agree, Somewhat Disagree, and Strongly Disagree (close to interval)

The entire thesis document can be downloaded from:

This research has been published in the 2023 Volume 62: Issue 1 of Performance Improvement Journal:

  • Hutchinson, D., & Chyung, S. Y. (2023). Evidence-based survey design: Adding “Moderately” or “Somewhat” to Likert scale options Agree and Disagree to get interval-like data. Performance Improvement, 62(1), 17-24. https://doi.org/10.56811/PFI-22-0012