Norman Cliff (born September 1, 1930) is an American psychologist.
He has had a number of research interests, including quantification of cognitive processes, scaling and measurement theory, computer-interactive psychological measurement, multivariate statistics, and ordinal methods.
One of his major contributions to psychometrics was the method for rotation of canonical components.
However, on the other hand, Cliff also suggested that there are viable and robust ordinal alternatives to mean comparisons.
He introduced a measure of proportional difference (or dominance) between two sets of data often referred to as Cliff's delta.