Learning In Practice

What the educators are saying

BMJ 2004; 328 doi: http://dx.doi.org/10.1136/bmj.328.7450.1244 (Published 20 May 2004) Cite this as: BMJ 2004;328:1244

The MBTI is a flawed measure of personality

Re: Clack et al (2004)

This study utlises the Myers-Briggs Type Indicator (MBTI)®, a
proprietary categorical classification of personality according to a
Jungian typology along four independent axes, Extroversion-Introversion,
Sensing-iNtuition, Thinking-Feeling and Judgement-Perception. Each
dimension has a zero point such that those falling on either side are
considered to be qualitatively different. This leads to 16 different and
exclusive personality types with which an individual can be labelled
(ENTP, ISFJ etc). An insight into the MBTI approach can be conveyed by
this quotation from advocates Tieger and Barron-Tieger (1993):

"A major premise of the Type model is that only one of the 16 Types
best describes each person — the Type to which you are born will be the
one you take to your grave. We may adjust our behaviors over time — or at
a party versus a funeral — but our personal Type remains the same for
life."

The MBTI may well be "the most widely used personality questionnaire
in the world" but its substantial limitations as a measure of personality,
as well as a tool for career counselling, are too numerous to list here
(see Pittenger 1993) but I would just like to highlight a few of the most
relevant.

The idea that there are 16 qualitatively different personality types
as revealed by the MBTI is demonstrably false (McRae and Costa 1989;
Stricker and Ross 1964). The only validity in the MBTI is in the
continuous personality dimensions used which are related to mainstream
psychometric personality measures (McRae and Costa 1989), however, in
practice, the MBTI is used as a typology, not as dimensions.

The MBTI personality dimensions seem to be distributed such that most
people fall between the two extremes around the boundary point of the
dichotomous category distinctions. Therefore people who are very small
distances apart on the dimensional measure are categorised as being
qualitatively different to one another because they fall either side of
the cut-off point between the types and are lumped in with much more
extreme scores that fall on the same side of the cut-off however far apart
they are on the dimension.

This flaw in the MBTI, as a measure of personality, undermines the
significance of the conclusions of Clack et al as it is not possible to
establish the magnitude of difference between doctors and their patients
on the personality dimensions.

While it seems a good idea to teach trainee doctors to try and
"ameliorate the potential difficulties resulting from such personality
differences, thereby improving the outcome of the interaction" it would be
unhelpful to include the MBTI and personality type in the communication
skills training of health care professionals, given its limited validity
and potential for misuse (Pittenger 1993).

Clack, G.B., Allen, J., Cooper, D. and Head, J.O. Personality
differences between doctors and their patients: implications for the
teaching of communication skills.
Medical Education, 38(2):177-186, 2004.

McRae, R.R., and Costa, P.T. Reinterpreting the Myers-Briggs Type
Indicator From the Perspective of the Five-Factor Model of Personality.
Journal of Personality, 57(1):17-40, 1989.

Pittenger, D.J. Measuring the MBTI ... and coming up short. Journal
of Career Planning and Employment, 54:48-53, 1993.

Stricker, L.J., and Ross, J. An Assessment of Some Structural
Properties of the Jungian Personality Typology. Journal of Abnormal and
Social Psychology, 68(1):62-71, 1964.

Tieger, P.D., and Barron-Tieger, B. Personality Typing: A First Step
to a Satisfying Career. Journal of Career Planning and Employment, 53:50-
56, 1993.

Competing interests:
None declared

Competing interests: No competing interests

21 May 2004
Paul R Matthews
Graduate Student
Dept. Psychiatry, Uni. Oxford, Warneford Hospital OX3 7JX
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