Please, help! I was sure that 5 points Likert scale (strongly agree/disagree) is ordinal. My advisor tells me that it is interval. I really feel like an idiot since the stat books say it's ordinal and somehow I must have misread. I really need to understand how is it an interval since this type of scale doesn’t represent equal intervals. Also, I have found that if the scale (such as mine) to be averaged (or factors) it becomes an interval variable. Can someone, please, comment on it as well... Thank you!
Hey,
This is a typical disagreement in the literature as well, with some authors attributing the scale to one type of scale over other. Perhaps that explains the discrepancies between the book and your Professor. They must be following different school of thoughts. Either way, Likert scale is an ordinal scale, however, since linguistic qualifiers are sometimes qualitatively equidistant (as in your case) on each side of central term (look at the distribution of the scale) in a well worded problem, it can also be treated as an interval scale. It relies heavily on the kind of categorical symmetry I.e. weighted averages between successive choices. The same serves as logical reasoning for your second question as to why your averaged scale behaves more like interval variable, that's cause the two are interchangeable in the scheme of things you're presenting your audience with.
Hope that serves as your answer let me know if you need any further explaination!
Syed Faizan Husain what do you mean by « weighted averages between successive choices »? Thank you for the answer !
By that I mean ratios between successive choices on the Likert scale having a symmetry about the middle term. Specifically I'm talking about the ratios of successive choices, from the middle to either sides, being constant in terms of qualitative influence on the outcome of the study.
Dear Yuliya quantitatively i think likert scale is assigned numerical values of 1 to 5 or 1 to 4 depending on your number of variable, which helps to calculate the mean and standard deviation of your responses. Maybe that is why your advisor sees it at interval.
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