The level of measurement is the kind of scale used to measure a variable. There are four levels of measurement: nominal, ordinal, interval, and ratio. The simplest level of measurement is called a nominal scale, which classifies items into two or more distinct categories on the basis of some common feature. A nominal scale groups items together into categories that can be named (the term nominal comes from the latin word for “name”). But it does not quantify the items in the way. Classifying subjects’ answers to a true/false test uses the nominal level of measurement. Subjects can circle “true” or “false” for an item, but not both. Nominal scaling is sometimes called the lowest level of measurement because it provides no information about magnitude. For some subject variables, however, it is the only type of scale that can be used. Political affiliation is a commonly used nominal measurement. You may be a democrat, Republican, Independent, or other. There is no difference in magnitude among these categories; you are not more or less affiliated if you belong to one party rather than another.