What does an interval scale indicate?

An interval scale indicates that order matters with no true zero. This type of scale reflects the relative positioning of items and the magnitude of differences between them, but it does not contain an absolute zero point. For example, temperature measured in degrees Celsius or Fahrenheit is an interval scale; while you can identify that 20 degrees is warmer than 10 degrees (indicating order), the zero point on these scales does not represent the absence of temperature, which is a key characteristic of a true zero that would exist in a ratio scale.

The distinction of having no true zero is vital in understanding how interval scales differ from other measurement types. While they can demonstrate the order and the differences between values, they do not allow for statements about how many times greater one value is compared to another, because the zero point does not signify a complete lack of the measured attribute.