Glossary of Statistical Terms: Definition Metric scale
A metric scale measures quantitative characteristics or variables. The term metric scale summarizes interval scales, ratio scales and absolute scales.
Quantitative numerical values allow for most of statistical calculations and comparisons. With metric scales, we can not only determine frequency (nominal scale) or rank (ordinal scale), but also the arithmetic mean ('average') of a set of values. But keep in mind that not all numerical values are also metric values. Postal codes, for example, are numbers but they are not metric values – it would not make sense to calculate an average of postal codes.
A simple example of a metric scale is the Celsius temperature scale. It is an interval scale. When given temperatures in °C, you can tell exactly what is warmer and what is colder, also the interval between 10°C and 20°C is equal to the interval between 30°C and 40°C. Furthermore, you can calculate an arithmetic mean, for example the average monthly temperature.
Please note that the definitions in our statistics encyclopedia are simplified explanations of terms. Our goal is to make the definitions accessible for a broad audience; thus it is possible that some definitions do not adhere entirely to scientific standards.