The Myers-Briggs Type Indicator (MBTI), one of the most well-known personality tests in America, has come under fire in the media recently because a significant body of evidence indicates that the test’s results are largely meaningless. This is a classic case of the popular press (belatedly) catching on to something that has been a virtual consensus among academic psychologists for a long time. And yet the MBTI continues to be widely used by companies and college career centers across the globe.
The test’s enduring popularity isn’t surprising. The MBTI sorts each test-taker into one of sixteen tidy personality types, each made up of overwhelmingly positive personality traits. These results can be a jumping off point for individuals to think about their communication styles and to explore different ways of viewing the world. Many organizations continue to use the test for team-building or improving collaboration between employees.
And unfortunately, some employers still use it for hiring, which we can say unequivocally is a mistake. The Myers-Briggs should NEVER be used as a pre-employment test or to help inform the hiring process. Here are four reasons why:
1. It’s based on outdated science.
The MBTI, originally developed over 70 years ago, is based on Carl Jung’s typological theory of personality. The MBTI divided certain elements of human personality into binary categories, sorting test takers into one of two categories across four traits. Modern psychological research shows that human personality cannot be accurately divided into discrete types, and tests that use this model tend to lack both reliability and validity. The study of personality has come a long way since then. More recent research tends to support a “trait over type” approach to personality, viewing personality traits like introversion/extraversion as dimensions or continuums rather than as binary absolutes. The most prominent personality test framework uses what is called the "Big Five" personality traits. These include five dimensions of personality that consistently emerge in empirical research: Agreeableness, Conscientiousness, Extraversion, Openness (to Experience), and Stability. The concept of personality "traits" measured on a continuum is now widely accepted, and has superseded the older personality "types" model that originated with Jung.
2. The test is not reliable.
Because the MBTI classifies people into types or buckets (described above in #1), it has poor reliability. One study on the MBTI demonstrated that when a sample population took the MBTI and then took the test again 5 weeks later, about 50% of people received different results. Because the test sorts people into types, a person who doesn’t have a strong inclination for one type over the other may be just a few questions away from being placed into an entirely separate category. This demonstrates that the test has poor test-retest reliability.
3. It isn’t predictive of job performance.
This is probably the most important reason you should never use the Myers-Briggs test for making hiring decisions. Studies have consistently demonstrated that the test fails to predict job performance in any meaningful way. If the main reason to use a pre-employment test is to predict job performance, then a test that lacks this predictive validity is essentially useless as an employee selection device.
4. The MBTI’s publisher itself explicitly discourages its use as a pre-employment test.
The guidelines put out by the Myers & Briggs Foundation very clearly state that “it is not ethical to use the MBTI instrument for hiring or for deciding job assignments.” This is because of reason #3, that the test is not predictive of job performance. The Equal Employment Opportunity Commission (EEOC) requires that every factor used to make hiring decisions be job-related and “properly validated for the positions and purposes for which they are used.” The MBTI lacks the predictive validity of many other professionally developed and validated employment personality tests, and therefore its use in the hiring process is not ethical.
While the Myers-Briggs personality test should never be used as a hiring tool, there are plenty of validated, professionally developed personality tests that do have predictive validity in the context of employment. When selecting a personality test for pre-employment testing, always look for tests that are backed by present-day psychological research and that have been validated to predict job performance for the types of positions you seek to hire. At a minimum, employment personality tests should have solid reliability and validity - which rules out the MBTI on both counts. Personality tests can be incredibly valuable tools for finding the best talent in your applicant pool, and using tests that produces meaningful, predictive results in the hiring process is the key to getting the most out of testing.