The Failure Of DISC, MBTI, And Other Personality Tests

Why personality tests are no reliable tools for hiring, firing, and setting up teams.

In many organizations, personality tests considering 16 or more traits, or 16 or more personality profiles, prevail. There is an entire personality assessment industry worth billions of dollars and no doubt you’ve come across at least some of them. But have you ever wondered whether they’re truly valid and reliable?

Two of the most famous tests are the Myers-Briggs Type Indicator, or MBTI, based on the personality types as proposed by Swiss psychiatrist Carl Jung (1875–1961), and the DISC assessment, based on the work of American psychologist William Moulton Marston (1893–1947), who also invented — with his wife Elizabeth — the polygraph, and who gave us the comic book character Wonder Woman. The latter test is most famous for the colors that are used to indicate a certain personality type. These colors have even become part of the lingo in many organizations. Who hasn’t heard colleagues utter words along the lines of, “Peter is really blue and just can’t get along with John, because he’s really green.” And therein lies one of the many dangers of these tests. People are stigmatized because of what comes out of such a test, taken at a particular time under particular circumstances.

Moreover, the science behind tests like these is feeble, to say the least. The theories of Freud and his pupil Jung have all but been debunked in later decades already. So, guess what you get with a test based on personality types, based on debunked theories? Pseudoscience is what you get, especially when it concerns its supposed predictive abilities. Myer-Briggs exhibits significant scientific psychometric deficiencies, including poor validity, poor reliability, measuring categories that are not independent, and not comprehensive. In other words, the test doesn’t measure what it purports to measure, it doesn’t have predictive power, it gives different results for the same person on different occasions, and it’s missing key elements, like measuring neuroticism.

DISC

If you look into the DISC assessment, things get even hairier. Psychologist Marston propounded his DISC Theory in his book “Emotions of Normal…