Decoding MBTI® “Scores” – What They Really Mean

by Cindy Stengel Paris on June 25, 2012

Not a glamorous topic, I agree, but an important one…one that is so misunderstood…

So check it out… are you an MBTI® practitioner who lines up workshop participants from high to low “scores” to explain the PCI (Preference Clarity Index) numbers shown on reported results?  Or are you just an interested party who has taken the Indicator and perhaps has been told that your PCI results indicate strength, weakness, skill, or development?  If either of those situations applies, this blog post is for you…you may not have correct information.  Take a look at what the MBTI Manual says on the topic:

“The preference clarity index is an estimate of relative confidence that a preference has been accurately identified.  Any other quantitative interpretation of MBTI results is incorrect and leads to misunderstanding and misinterpretation.” (The MBTI Manual, p.121)

I know this statement seems counterintuitive, especially when you look at the bar graphs on MBTI computerized reports that depict the PCI and the PCC (the Preference Clarity Category associated with the PCI, which can be Slight, Moderate, Clear, or Very Clear).  And this doesn’t fit the framework we are accustomed to for interpreting “scores” either.  If you study the development and construction of the instrument, though, you will be able to put it all together.  Or, you can keep reading and I will spare you the technical details, impart the highlights, and hopefully shed some light on the issue.

Isabel Myers’ sole purpose in creating an assessment was to help people gain access to Jung’s theory of psychological types.  She wanted people to begin to explore what their type might be. She thought if people were able to understand themselves better, they would be happier, live a more fulfilled life, and learn to appreciate differences in others.  So, she created a paper and pencil instrument, carefully constructed to sort people into categories to which they already belonged.

How did she do this?

She observed the behaviors of friends and family and tested her hypotheses about those behaviors and how well they indicated a possible preference for a Jungian type category (thus it was named the Myers-Briggs Type Indicator®).  She developed questions based on those behaviors, on four separate scales of opposites (the dichotomies of E-I, S-N, T-F, and J-P), to reflect Jung’s dichotomous theory.  The object was to have people select answers to each question in the direction that would be most true for them.  In effect, people would be casting a vote for one side of a dichotomy over another, as they answered the questions.  This is called “forced choice”.

So, the questions on the indicator simply sort people into opposing categories.

The more votes someone casts in the direction of one pole of a dichotomy over its opposite, say Extraversion over Introversion, the more we can be confident that the person is selecting his or her true preference.  In fact, the computer generated PCI is a ratio showing how consistently a person answered the questions on that scale compared with the maximum possible score achievable on that scale (Manual p. 148).  Essentially, a person’s responses are being compared to his or her own responses!

Myers used an analogy of “straws blowing in the wind” to impart the concept.  If you see one piece of straw blowing in a field, you cannot tell the direction from which the wind is blowing.  Yet, if you see a field of straw blowing in the wind, you can more easily identify the direction of the wind.  The more a person answers certain word phrases and selects from word pairs in the direction of a particular preference, the more it indicates that the preference may be true for them.  It is true for “type watching” as well.  We can make hypotheses about the preferences someone may be using by looking at their behavior patterns.

If you stop to think about it, it makes sense that MBTI reported results have to be interpreted differently than the “scores” on other personality instruments because the MBTI, after all, it not a trait instrument but a type instrument There are many observable behaviors that correlate with each of the type preferences; the MBTI Indicator is not simply trying to “score” a single individual dimension of personality.

I keep putting the word “scores” in quotes because the word itself causes people to think in terms of quantitative comparisons (good/bad, strong/weak, skilled/unskilled).  Myers knew that there would be a tendency for misinterpreting “scores” and so thought it best to talk in terms of the PCC only (Lawrence and Martin, Building People, Building Programs).

If we can’t say that the PCI quantifies preferences, what can we tell our clients?

This brings me back to the initial quote from the Manual.  We can say that the PCI numbers tell us the likelihood that a person’s preferences have been correctly reported.  Research tells us that the clearer the preference, the more confidence we can have that the person selected his or her true preference.  When a person’s results show a Slight preference, then, we simply have less confidence that a true preference has been reported than with the other categories (Moderate, Clear, and Very Clear) and it is our job to assist them in exploring other types.

If all of what I have been saying is true, and MBTI results do not necessarily give us our type, how can we help clients determine what their true type actually is? Why bother using the instrument at all?

Myers meant for the Indicator to be one hypothesis for exploring what one’s typology might be.  She also wrote type descriptions from her knowledge of the interaction of the preferences (Introduction to Type) and her intent was for the type descriptions to be used together with the Indicator for self-discovery.

Today, practitioners have all sorts of exercises and methods for helping people discover their “best-fit” type, but we must allow our clients to do some exploration and make sure we give them the opportunity to self-select their type before handing out their reports and revealing their reported type [scroll down to Verifying Your Best Fit Type:].  For, in the end, as with any self-report instrument, how true the results are for any one person is up to that one person.

And in my work, I have found that using the Indicator, and what it has to offer,  is the best place to start.

Copyright,The People Skills Group,
LLC, 2012

{ 2 comments… read them below or add one }

Daniel July 2, 2012 at 10:47 pm

“The preference clarity index is an estimate of relative confidence that a preference has been accurately identified. Any other quantitative interpretation of MBTI results is incorrect and leads to misunderstanding and misinterpretation.” (The MBTI Manual, p.121)

This is way too important than anything. Many people in China misunderstanding the “Scores”, they thought it shows the “Capabilities”….

Cindy Stengel Paris July 3, 2012 at 10:58 am


Thanks for the comment! Yes, this is a common misunderstanding of the MBTI scores; we are used to looking at test results in those terms. If I can quote the manual again,

“The most frequent error that occurs regarding the numerical portion of MBTI results is assuming that clarity of preference implies excellence: it is incorrect to assume that a person with a [PCI] of N30 has a better command of Intutition than a person with N15. A larger number simply means that the respondent, when forced to choose, is more clear about what he or she prefers.” (p.121).

So the MBTI is not “measuring” skill, or for that matter anything else. It is sorting people into categories; and those categories are what the person preferred at the time they took the instrument; so, even though they preferred their selection at the time, we need to always have them self-select first. Bob McAlpine once used the analogy of multiplication and division to help his trainees understand self selection and reported type — one verifies the other.

I appreciate the comment and hope that you can let people know about our site which is a resource for sound, ethical information!


Leave a Comment

Previous post:

Next post: