You searched for: “psychometrics
psychometrics
That branch of psychology centering on the study of various mental measurements, making use of psychological tests designed to reflect differences among individuals on one or more of the several dimensions of mental ability; such as, intelligence, aptitudes, interests, manual abilities, special abilities, or disabilities.

It includes the devising or standardization of various tests and the development or application of statistical techniques that are particularly appropriate for the analysis of mental test data.