A scale of measurement in which differences between values can be quantified in absolute terms and a fixed zero point is defined, as for example in measurements of length in centimetres or age in years. In a ratio scale, equal differences between scores represent equal differences in the attribute being measured, and a zero score represents complete absence of the attribute. It is only when measurement reaches the level of a ratio scale that it is meaningful to describe a score as twice the value of another score, for example. See also measurement level, scale (1). Compare absolute scale, interval scale, log-interval scale, nominal scale, ordinal scale. [From Latin ratio a reckoning]
Subjects: Psychology — Mathematics.