Where this was said
The MBTI: A Corporate Scam Built on Jungian Mythology
At 57:58 · chapter starts 46:00
Mark traces the MBTI's unlikely origin story: Katherine Briggs obsessively translated Carl Jung's work for American audiences, then her daughter Isabel — a novelist without a psychology degree — saw an opportunity when women flooded the WWII workforce and needed rapid job-fit assessment. She built a test from her dining room table, combining Jung's two 'attitudes' and four 'functions' with a fourth spectrum she essentially invented (perceiving vs. judging). Zero peer review, zero control group. The test spread virally through government agencies, then corporate consultants, until by the 1980s 89 of the top 100 global companies administered it. Today 2 million people per year take it in corporate settings. Drew then lists the scientific indictments: 33–50% get different results weeks later; it uses binary categories on what are actually spectra; it doesn't measure neuroticism; and unlike the Big Five, it cannot reliably predict job performance, relationship satisfaction, or mental health outcomes.
An estimated 2 million people per year take the MBTI in a corporate setting, despite it lacking scientific validation and failing to reliably predict job performance or relationship outcomes.
A third to half of MBTI takers get a different result just weeks later. It has no measure of neuroticism — arguably the most predictive trait for mental health. It cannot reliably predict job performance, relationship satisfaction, or any major life outcome. The Big Five does all of this consistently. The MBTI survives purely because it flatters and labels us, not because it works.
Between a third and half of people who retake the MBTI just weeks later get a different personality type, revealing it as unreliable and closer to a coin flip than a valid test.
