Levels of Measurement

Levels of measurement

The different ways in which variables can be categorised, ordered, or scaled, which determines the type of statistical analysis that can be used (Nominal, Ordinal, Interval, Ratio).

Nominal data

The lowest level of measurement, where data are categorised without any order or numerical value (e.g., gender, hair colour).

Ordinal data

A level of measurement where data can be ordered or ranked, but the differences between values are not necessarily equal or meaningful (e.g., Likert scales, rankings).

Interval data

A level of measurement where data can be ordered, and the differences between values are meaningful and equal, but there is no true zero point (e.g., temperature in Celsius or Fahrenheit).

Ratio data

The highest level of measurement, where data can be ordered, differences are meaningful, and there is a true zero point, allowing for meaningful ratios (e.g., height, weight, time).