Psychometrics

From ArticleWorld

Psychometrics is the study of the measurement of psychological constructs such as intelligence, knowledge, abilities and personality. There are two main interests of the approach which are the development of the instruments and how they are used to measure the variables concerned and, secondly, the theory behind the measurements.

The initial aim of psychometrics was to measure intelligence but the interests have broadened since then. To measure psychological phenomenon is very difficult due to the fact that they are unobservable and in order to measure them, one must first define and quantify them. The majority of psychometric research has concentrated on doing just that but critics of the discipline maintain that such a task is too difficult to be done scientifically.

Charles Spearman

The pioneer of psychometrics is considered to be Charles Spearman, a psychologist in the early 1900’s. His work was in the application of mathematical methods to the analysis of the mind. Two of his contributions were factor analysis, which is the statistical method most in use in psychometrics today, and Spearman’s rank correlation coefficient, a non-parametric measure of correlation.

Psychometric instruments

The first instruments to be used in psychometrics were IQ tests used to measure intelligence. Psychometrics is used widely in educational assessments in the form of Classical Test theory, Item Response theory and Rasch measurement models. The Minnesota Multiphasic Personality test is used in personality testing and the Likert scale is used to test attitudes.

Most tests used in psychometrics are based on reliability and validity both of which can be tested mathematically.