Psychometrics is the science of psychological assessment and is usually seen as a branch of psychology, but its impact is much broader than this. The scientific principles that underpin psychometrics apply equally well to assessment in education and in clinical or occupational contexts, and the early psychometricians were equally at home in all these fields. Since then, paths have often diverged, but have generally reunited as the importance of advances made in each context come to the attention of those in the others.

Currently, the great advances being made in statistical modeling are significantly impacting the application of psychometrics in both the educational and occupational fields. The lead comes from psychometric epidemiologists, who analyze large-scale survey data, including questionnaires. These are exciting times. But the history of psychometrics goes back a long way.

Employers have assessed prospective workers since the beginning of civilization, and have generated consistent and replicable techniques for doing this. China was the first country to use testing for the selection of talent. Before 500 BC, Confucius had argued that people were different from each other. In his words ‘their nature might be similar but behaviors are far apart’, and he differentiated between ‘the superior and intelligent’ and ‘the inferior and dim’. Mencius believed these differences were measurable.

He advised ‘assess, to tell light from heavy; evaluate, to know long from short’ (Jin 2001). Xun Zi (310 BC to 238 BC) built on this theory and advocated the idea that we should ‘measure a candidate’s ability to determine his position (in the court)’ (Qi 2003). Thus, over 2000 years ago much of the fundamental thinking that underpins intelligence testing was already in place, as were systems that used testing in the selection of talents.