A nominal scale is essentially one that consists of a number of categories, with no sense of ordering. So the only operation that is meaningful is a test for equality (or inequality). An example of a nominal scale might be programming languages. (See measurement scales.) Nominal values are often used in regression studies by converting each element in the scale to a dummy binary value. If the nominal scale has n elements, it will be represented by n - 1 dummy variables; the nth condition occurs when each of the n - 1 dummy variables takes the value zero.

This entry was last updated on 5 August 2008