Measurement Levels, Nominal/Categorical

As the lowest order of measurement scaling, a nominal scale transforms a labeled class of objects into a number. Nominal scaling depends upon mutually exclusive groups. Each distinct group or category is assigned a number. Nominal scaling assumes that no meaningful relationship exists between the numbers. It is understood that the number is substituting for the group name or label. It is also assumed that all members of a population could fall within the identified groups. Categorical scaling is equivalent with nominal scaling, since both indicate that a number is replacing a category or name. This type of measurement is most often used to establish the frequency or quantity of something. It is used to answer questions about “how many” or “how often” something was ...