I’ve seen many people getting confused for the Likert scale type. Many people say that it is ordinal data, and many say that it is interval data. Which exactly is it?

The easiest way to learn the difference between the two is that an ordinal scale is a set of values, e.g. all positive integer numbers 0, 1, 2, 3, …. together with the common “less than” relationship, x < y, defined for every pair of such number. Whereas, interval scale has an additional structural component. Thus, an ordinal scale can never be an interval scale.

You can also find out whether you are dealing with an ordinal or an interval scale by the following way:

You are dealing with an ordinal scale if you cannot consistently define and measure distances between objects you are interested in, but it is possible to rank order those objects. And, if you cannot even rank the considered objects, then you aren’t dealing with ordered objects on an ordinal scale ~ probably all you have is an interval scale.