Monday, 18 April 2022

Evidence and MBTI

Last year I read Merv Emre's book on the Myers-Briggs Type Indicator (2018), which was a fascinating read. I had expected a clear-eyed exploration of the type indicator, and I think the resulting book was fair in its approach to the story of the development of the MBTI tool. Ms Emre's book delivered more than a hint of admiration for the doggedness and drive of the tool's founders: Katharine Briggs, and her daughter, Isabel Briggs-Myers (2018). 

This book enlightened me in a number of ways. For example, I had not realised the considerable amount of work undertaken between 1957 to 1975 from the Educational Testing Service (ETS) in attempting to validate the MBTI tool, which was pretty much an epic fail. It was only after ETS had given up on validation and returned the rights to Katharine Briggs - who by that time had dementia - and her daughter Isobel Myers-Briggs that the tool actually took off. The rise and rise of MBTI was via a deal with Consulting Psychologists Press (CPP) in California, which still markets the tool (Emre, 2018).

I found the chapters on the issues with validation to be very enlightening. There were clearly issues with replicability, construct and content validity, and generalisability. Isabel Myers-Briggs was reported as having closely held the process of scoring the returned, completed test scripts, appearing reluctant to allow computer scoring of data ...which was likely to have been more independent and objective (Emre, 2018). Other sources also mention issues of validity: MBTI's "ipsative construction of the questions, lack of criterion-related validity, and its tendency to be a 'feel good' instrument" are common complaints (Wood & Hay, 2013, p. 54). Test re-test replicability is as low as 50%: half those who have taken the test will fail to get the same result when retaken after three months (Emre, 2018; McCaully & Moody, 2007; Menand, 2018). 

Despite my management and career background - or perhaps because of it! - I am a personality instrument skeptic. I am happy to use a personality instrument as a starting point for a career conversation: but not as an end point to categorise people; to put them in a box; to confine them. 

Further, I like to have sound evidence of reliability, validity and generalisability, which many tests cannot provide; including MBTI (Mastrangelo, 2001). For me, my MBTI instrument type test re-test has always been consistent - unlike RIASEC, where my test-re-test is consistently inconsistent (I suspect that my interests are too broad to return a meaningful RIASEC score). What is interesting though is that - in light of Ms Emre's book (2018) - when I reread my MBTI ENTJ type profile, the actual type wording now seems to possess the vagueness of a horoscope:

"The ENTJ personality type is a competitive, highly motivated and focused person who sees just about everything by focusing on the bigger picture. ENTJs thrive by setting long-term goals and making highly analytical decisions, and they often do well in high-stress leadership roles. ENTJ types tend to see things in black and white, or by the numbers. In personal relationships they are fair, measured, and supportive" (MBTI Online, 2021).

So... hang on a minute. Competitive AND highly analytical AND fair AND supportive AND black and white AND big picture... right. Some of these things are not like the others. 

What is particularly troubling is that MBTI has grown so popular that it is now blindly being used for making decisions in organisations; to determine who manages; who is in the team; who is hired; and who is let go (Macabasco, 2021). Additionally, MBTI also appears to be being used the classroom like the debunked learning styles (here) to categorise how different students learn (Emre, 2018, 2020; Harel, 2021; Macabasco, 2021). 

We should not be making such decisions without good quality evidence. And - in my view - MBTI does not yet provide good enough quality evidence. 

An HBO documentary documentary, "Persona: The Dark Truth Behind Personality Tests", was released on HBO last year (Macabasco, 2021). While I have not yet seen this film, it apparently explores the pervasiveness of personality testing use in organisational HR decisions. I can't wait to see it, but I am sure it will be somewhat depressing viewing. Ah well. 



  • Emre, M. (2018). The Personality Brokers: The Strange History of Myers-Briggs and the Birth of Personality Testing. Penguin Random House. 
  • Emre, M. (23 December 2020). TED-Ed: Do personality tests work? [video].
  • Harel, A. (29 April 2021). The Problems With Using Personality Tests For Hiring. Vervoe.
  • HBO Max (23 February 2021). Persona | Official Trailer [video].
  • Macabasco, L. W. (4 March 2021). 'They become dangerous tools': the dark side of personality tests. The Guardian.
  • Mastrangelo, P. M. (2001). Myers-Briggs Type Indicator [Form M]. In B. S. Plake & J. C. Impara (Eds.) The Fourteenth Mental Measurements Yearbook (pp. 818-820). Buros Center for Testing.
  • MBTI Online (2021). ENTJ.
  • McCaully, M. H. & Moody, R. A. (2007) Multicultural applications of the Myers-Briggs Type Indicator, in L. A. Suzuki:, J. G. Ponterotto, & P. J. Meller (Eds.), Handbook of Multicultural Assessment: Clinical, psychological, and educational applications (3rd ed., pp. 402-424). Jossey-Bass.
  • Menand, L. (10 September 2018). What Personality Tests Really Deliver. The New Yorker.

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