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.
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At 56:35 · 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.
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.
Bhanu grew SiteGPT to $13,000 monthly recurring revenue entirely through organic channels, spending nothing on paid marketing.
More than 1 million people have visited SiteGPT's website since launch in March 2023, all through organic channels.
Approximately 90% of SiteGPT's Google search traffic comes from the free tools Bhanu built, not the main product pages.
Bhanu sold his first SaaS product, Feather, for $250,000 so he could focus fully on the faster-growing SiteGPT.
SiteGPT has generated approximately $500,000 in total revenue since its launch in March 2023.
The average customer lifetime value for SiteGPT is approximately $1,700 to $1,800, which Bhanu considers unusually high.
SiteGPT receives around 50,000 visitors per month, of which about 200 convert to leads and 60 start free trials.
SiteGPT hit $10,000 MRR within its very first month of launch, driven largely by early traction in the AI chatbot space.
Despite strong download numbers, PropGPT could not push past $1,000–$2,000 MRR due to poor product retention.
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