Читать книгу Applied Univariate, Bivariate, and Multivariate Statistics - Daniel J. Denis - Страница 38

In addition to categorizing objects into classes, measurement at the ordinal level imposes an order relation between objects. For instance, if $ is greater than * for some characteristic that these symbols represent, then we have measurement at the ordinal level. The imposition of an order relation is fundamental to any sort of true measurement. Consider that if your measurement system does not even allow you to say one thing has more of a characteristic than another, what could be the purpose of even measuring?

Ordinal measurement, however, does not say anything about the precise amount of magnitude between objects. For example, first place, second place, and third place in a race constitute measurement at the ordinal level, but that you finished second does not immediately tell us the distance between first and second, or the distance between second and third. To speak of distances between objects, we require measurement at the interval level.