If you have ever been told you are an INTJ, ENFP, or "any combination of four letters," you have met the Myers-Briggs Type Indicator (MBTI). It is the most famous personality test in the world. It is also the one most psychologists no longer trust.
This post is not a hit piece. The MBTI is fun to read and easy to share. But when researchers ask the harder question — "does this test actually predict anything?" — the answer keeps coming back the same way. The Big Five does. The MBTI mostly does not.
Here is what the research shows, in plain language.
The two tests, in one paragraph each
The MBTI sorts people into 16 types based on four either/or choices: Introvert or Extravert, Sensing or Intuitive, Thinking or Feeling, Judging or Perceiving. You get a label like INTJ.
The Big Five (also called OCEAN or the Five-Factor Model) gives you a score on five separate traits: Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. You get a number on each, not a type.
Where the MBTI breaks down
Three problems keep showing up in the research.
1. The results are not stable. When people retake the MBTI a few weeks later, between 39% and 76% get a different type 1. If your test result changes that often, it is not really measuring something solid.
2. The four-letter types force a fake either/or. Real human traits sit on a smooth scale. Most people are not deeply introverted or extraverted — they are somewhere in between. The MBTI takes that gray middle and pushes it to one side or the other. A person who scores 49% on extraversion gets a different label than someone who scores 51%, even though they may be almost identical.
3. The test does not predict much. Research has tried to use MBTI scores to predict job performance, life satisfaction, and relationship outcomes. The links are weak. A 1991 National Academy of Sciences review concluded there was "not sufficient, well-designed research to justify the use of the MBTI in career counselling programs" 2. That conclusion has not aged out.
Why the Big Five holds up
The Big Five came out of a different process. Researchers started with the words people actually use to describe each other in everyday language, then used statistics to find which clusters of words kept appearing together across decades, countries, and languages 3.
What survived that process was five broad traits. And those five traits, unlike MBTI types, do predict real-life outcomes:
- Conscientiousness predicts job performance and income better than most other traits 4.
- Neuroticism predicts how someone reacts to stress, and is a strong predictor of relationship problems 5.
- Openness predicts who chases creative or unusual paths in life.
- Trait scores stay relatively stable over years, but they can also shift slowly with experience 6.
That last point matters. Big Five traits are not fixed labels. They are patterns that may change. Your score this year may not be your score in ten years. The MBTI, by design, says you are a fixed type — even though the test itself keeps giving you different types.
"But the MBTI feels so accurate"
This is real, and it is worth taking seriously.
When you read your MBTI description, it often feels surprisingly true. There is a name for that: the Barnum effect. People tend to rate vague, mostly positive descriptions as personally accurate, even when those descriptions could fit almost anyone 7. Horoscopes use the same trick.
The Big Five sounds less satisfying because it does not hand you a tidy identity. Telling someone "you are 73rd percentile on Conscientiousness" is less fun than telling them they are an architect type. But the 73rd percentile is the part that holds up across tests.
What to do with this
If you have already taken the MBTI and found it useful for self-reflection, that is fine. A test does not need to be scientifically perfect to be a useful prompt for thinking about yourself.
But if you want a measurement you can lean on — for career decisions, relationship questions, or just understanding your own patterns — the research points clearly at the Big Five. The good news is the most validated free Big Five test, the IPIP-NEO-120, is in the public domain and takes about 12 minutes 8.
That is the assessment behind every Defaults report. We use it because the research says we should.
Take the free Big Five assessment →
References
Footnotes
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Pittenger, D. J. (1993). The utility of the Myers-Briggs Type Indicator. Review of Educational Research, 63(4), 467–488. https://doi.org/10.3102/00346543063004467 ↩
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Druckman, D., & Bjork, R. A. (Eds.). (1991). In the Mind's Eye: Enhancing Human Performance. National Academy Press. ↩
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Goldberg, L. R. (1990). An alternative "description of personality": The Big-Five factor structure. Journal of Personality and Social Psychology, 59(6), 1216–1229. https://doi.org/10.1037/0022-3514.59.6.1216 ↩
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Roberts, B. W., Kuncel, N. R., Shiner, R., Caspi, A., & Goldberg, L. R. (2007). The power of personality: The comparative validity of personality traits, socioeconomic status, and cognitive ability for predicting important life outcomes. Perspectives on Psychological Science, 2(4), 313–345. https://doi.org/10.1111/j.1745-6916.2007.00047.x ↩
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Solomon, B. C., & Jackson, J. J. (2014). Why do personality traits predict divorce? Multiple pathways through satisfaction. Journal of Personality and Social Psychology, 106(6), 978–996. https://doi.org/10.1037/a0036190 ↩
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Roberts, B. W., & Mroczek, D. (2008). Personality trait change in adulthood. Current Directions in Psychological Science, 17(1), 31–35. https://doi.org/10.1111/j.1467-8721.2008.00543.x ↩
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Forer, B. R. (1949). The fallacy of personal validation: A classroom demonstration of gullibility. Journal of Abnormal and Social Psychology, 44(1), 118–123. https://doi.org/10.1037/h0059240 ↩
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Johnson, J. A. (2014). Measuring thirty facets of the Five Factor Model with a 120-item public domain inventory. Journal of Research in Personality, 51, 78–89. https://doi.org/10.1016/j.jrp.2014.05.003 ↩