The term “nominal” means to name. There are two basic requirements for nominal measurement scales:
1. All members of one category must be assigned the same numeral.
2. No two categories are assigned the same numeral.
Some nominally scaled variables have only two categories. These are called dichotomous variables. This means that only two numbers can be assigned to each of the categories, respectively.
Example: Gender with Males (0) and Females (1)
Some have more than one category.
Example: Marital Status with Single (0) Married (1) and Divorced (2)
Don’t Make This Mistake!
Sometimes, doctoral students think the variable is female or male instead of gender with two categories. Ask yourself: What variable are the individual categories representing? The answer should be the variable itself and not its categories!
Return from nominal measurement scales to variables and instruments