A true zero point is a feature of:

Concept

A measurement scale specifies what comparisons and mathematical operations its values support.

A true zero represents the complete absence of the measured quantity, so ratio statements such as twice as much are meaningful.

Application

Among the listed scales, the ratio scale has ordered values, equal intervals, and a true zero. Therefore both differences and ratios can be interpreted.

Contrast

• Nominal scale: classifies observations into categories without a numerical order.

• Interval scale: has ordered, equal intervals, but its zero is an arbitrary reference point.

• Ordinal scale: ranks observations, but the gaps between ranks are not known to be equal.

Result

The scale characterized by a true zero is the ratio scale.