What is an ordinal scale?

An ordinal scale is indeed a scale that ranks data but does not consist of exact differences between each rank. This means that while you can determine which data points are higher or lower in relation to one another, you cannot quantify the precise difference between those ranks. For example, if you were to rate satisfaction with a service on a scale of "poor," "fair," "good," and "excellent," you can identify that "excellent" is a higher level of satisfaction than "good," but you cannot say how much better "excellent" is compared to "good" in numerical terms.

In contrast, the other scales described would measure attributes differently. A scale without order or ranking suggests that the data points are simply categorized without any hierarchy, which does not apply to an ordinal scale. A scale with fixed distances refers to an interval scale, which allows for precise quantitative comparisons between data points, something that ordinal scales do not offer. Lastly, a scale that has a true zero point describes a ratio scale, which includes an absolute zero that allows for meaningful comparisons such as twice or half, again differentiating it from the characteristics of an ordinal scale.