Nominal scale

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Definition

Nominal scale A measurement system that assigns names, labels, or categories to the possible values of a variable, such that the set of names does not imply a particular order or hierarchy. The assigned names must be mutually exclusive. One of four levels of measurement. A variable measured on a nominal scale is known as categorical or qualitative. Although a variable coded using a nominal scale may appear numeric (e.g., gender coded as female=1, male=2), the numbers should be used only as labels, such that addition/subtraction and multiplication/division are not appropriate.

Examples

The following are examples of nominal variables:

• Gender (male, female)
• Handedness (left, right)
• Eye color (brown, blue, green, hazel)
• Online workshop participants' country of origin

Web Resources

Online Statistics: An Interactive Multimedia Course of Study, Chapter: 1. Introduction, Section: Levels of Measurement. Wikipedia's Level of measurement, Nominal scale.

Acknowledgements

Portions of this entry were adapted from

• Nominal Scales at Online Statistics Education: An Interactive Multimedia Course of Study. Project Leader: David M. Lane, Rice University. Retrieved 30 January 2012.