It’s difficult to work out which jobs will suit you. To help with this problem, a variety of personality tests have been developed. It’s hoped these tests provide understanding of your personality in a way that can be used to predict what sorts of job might suit.

One of the most widely used tests is the Myers-Briggs type indicator (MBTI). According to Malcolm Gladwell, 2.5 million Americans every year take the test and 89 out of the Fortune 100 companies use it. (1)

But it turns out there are plenty of reasons to be sceptical about its use in choosing careers.

Does the MBTI actually give you a meaningful type?

The MBTI is normally used as a typology. It uses four measures of personality and for each measure people are classified into one of two types. The results of these are then combined to summarise the overall personality type. Since there are four measures, there are 16 possible overall personality types. The assumption that we can be classified into types like this turns out to be false.

The distribution is not bimodal
If this approach was right, we’d expect the distribution of scores on the Myers-Briggs measures to be bimodal – most people should be in either one or the other. The distribution is not like this – most people score between the two extremes. (3) For example, most extraverts and introverts are fairly close together on the Extravert-Introvert scale with only a few people at either extreme. Because of this, the strict dichotomy leads to a false view of people’s personalities.

The types are not stable over time
If the MBTI is to be used when choosing a career, it must detect stable personality types and not change much over time. So if someone is given the MBTI one day and then given it again a few weeks, months, or years later their classification shouldn’t change much. But given that most people’s scores lie in the centre of each measure, it doesn’t take much change in the answers to some of the questions to lead to that person being reclassified as a different type. When people have been given the test on two occasions, the degree to which people’s typology stays the same is lower than you would expect if it detected stable personality types. (4)

The responses don’t cluster
If the Myers-Briggs refers to genuine personality types, we should be able to analyse responses to the questions and find that certain answers cluster together in ways that reflect the personality types. We should be able to find underlying factors in the data that are similar to the Myers-Briggs types. However, when factor analysis has been done on responses to the Myers Briggs questionnaire, the factors found did not correspond closely with the dichotomous Myers-Briggs measures. (3)

Does it predict job performance?

When thinking about career choice, it is important to have a personality test that predicts both job choice and work success. Whereas there is strong evidence that the consensus personality test in psychology (the big five personality test) predicts job performance (3,5) there is no such consensus about the MBTI.

Origins in pseudo-science and possible reasons for popularity

The MBTI was developed on the basis of work by the psychoanalyst Carl Jung. Since both Jung’s theories and a typological approach to personality are no longer accepted by mainstream psychology there is little reason to expect that the MBTI is a fruitful approach to understanding personality. Indeed, despite it’s unscientific nature, the theory behind the MBTI may be one of the reason’s for it’s popularity. Unlike more descriptive personality tests, the MBTI is linked to a theory of psychology that can be used in the interpretation of the questionnaire – this means that people can delve further into the theory to interpret their test results. The test is made even more satisfying because the “[T]he descriptions of each type are generally flattering and sufficiently vague so that most people will accept the statements as true of themselves.”(2) This contrasts with mainstream psychology’s big 5 personality test, which can show someone in a specific negative light by giving them a high score on neuroticism and a low score on conscientiousness.

Conclusion

A National Academy of Sciences committee concluded in 1992 that “at this time, there is not sufficient, well-designed research to justify the use of the MBTI in career counselling programs”. (6) The evidence is little better now.

The continued used of the MBTI is even more mysterious given the existence of the Big 5 personality test. As we’ll show in the next post, the Big 5 is the consensus personality test in psychology, as has been shown to have predictive power in a wide variety of domains, including job performance.

1. Gladwell, M. Personality plus. New Yorker 43 (2004).
2. Pittenger, D. J. Measuring the MBTI… and coming up short. Journal of Career Planning and Employment 54, 48–52 (1993).
3. Pittenger, D. J. Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research 57, 210 (2005).
4. Boyle, G. J. Myers?Briggs Type Indicator (MBTI): Some Psychometric Limitations. Australian Psychologist 30, 71–74 (1995).
5. Locke, E. Handbook of Principles of Organizational Behavior: Indispensable Knowledge for Evidence-Based Management. (John Wiley & Sons: 2009).
6. Druckman, D. & Bjork, R. A. In the mind’s eye: Enhancing human performance. (National Academies Press: 1992).