For people who don't understand, I'll be specific. The MBTI Inventory asks questions about your preferences. All it measures is your responses to the questions. If your answers change, your result changes.
The MBTI will give you the same Type code every time if you answer the questions the same way. Millions of people do answer the questions the same way. "It should be understood that the MBTI® instrument meets and exceeds the standards for psychological instruments in terms of its reliability. (ref)".
Perhaps because it involves humans, however, many people attribute "different results" for the MBTI to a fault in the assessment ("it asks bad questions!"). The fault obviously cannot lie with the person answering, i.e. "I can't possibly be inconsistent in my understanding of my internal preferences!"
If we make an analogy between the MBTI and a thermometer, your answers are analogous to a cup of tea. The measured temperature of the tea can vary, depending on when it's poured, the temperature of the room, the type of cup, how long ago the tea was poured, the temperature of the water used, and many other factors.
If you think that you can use the same thermometer on many cups of tea and always get the same result, you're not thinking clearly. This only works if you very carefully regulate the properties of the cups of tea.
If your MBTI results change, that means that the "you" answering the questions today is not responding the same way as the "you" answering the identical questions six months (or whenever) ago. If your result changes, you should not claim that the MBTI is unreliable. Instead, the much more interesting question you should ask is, "why did my answers change?
A friend of mine, Mary Miscisin (PersonalityLingo.com) suggests this answer when people ask: Is this valid?
"Let’s make one thing perfectly clear: in our view, asking if a specific personality test is “valid” is a red herring – this question misleads or distracts from the relevant issue. The fact is that the [system] is not a test with right or wrong answers and thus the statistical concept of “validity” is being misapplied. The [system] is a TOOL for self-identification and self-awareness.
Of course when using a tool, there are many questions one could ask: “Is it safe?”, “Is it practical?”, “Is it the right tool for the job?” and so on... However, we invite you consider one of the most important questions when using a tool:
“Is it useful?”
Consider for a moment that you are about to use a hammer and someone stops you and asks, ”Is that hammer valid?” You would likely look at them puzzled and respond, “What do you mean, is it valid?” Your next inquiry might be, “Valid for what?” It seems like a rather strange question in that context, doesn’t it? However, if someone asked you if a hammer is useful we can all agree that the answer is a resounding YES!
Another friend has started to tell people that yes, the MBTI is a test and it does have correct answers. It is possible to "pass" the MBTI and many people do "fail" (at least, the first time they take it.)
The people who pass know themselves and their inner preferences well. The people who fail, do not.
(I would add that the practitioner administering the MBTI may also be to blame if that person does not set expectations properly before the client takes the inventory.)
As my friend says:
The question of validity often arises around the mention of MBTI, Myers-Briggs. Yes - it is a fundamentally flawed concept. More people fail it than pass the Myers-Briggs test. By passing it, we mean that they come up with the right answer.
It relies too heavily on self-awareness. How many people do you know who can truly assess themselves objectively? This is the weakness of the MBTI assessment instrument - so it gets easy blame.
Because there actually is a right and a wrong result, I finally gave in; so now, rather than echoing the long-held phrase "it's not a test", I give it back.
I may now say: Yes; it's a test. It's like recognizing yourself in a mirror, but a lot more difficult. Can you pass?
The traditional ambiguity is nice for those who have high Openness. For those whose vulnerability has been threatened, however, authenticity is constrained, rather covered with a mask.
Imagining that we can be whatever we want to be creates a certain risk. We may anguish over failing to accomplish something that we never should have selected in the first place. It is more effective to be the best version of ourselves rather than an inadequate version who we interpreted from others that we were supposed to be.
This is not limiting at all; far to the contrary, self-understanding increases the chances of a fulfilling career, and a well-selected life-partner.
I wish that CPP, Inc. did not feel that they need to protect the questions on the MBTI as Intellectual Property. It would be easier (and much better, I think) if Type Practitioners and clients could have access to all questions and the way the client answered each one. Keep the scoring algorithm private. Don't let the questions leave the room. But make the full results, questions + answers, available to the practitioner and the client!
Also, I think that every person who takes the MBTI should be assigned an ID number that they can use again if they ever take the MBTI again. (I'm talking about the real MBTI, not the "knockoffs" available on the web). That (anonymized) ID number would allow CPP and practitioners to determine accurate (not anecdotal) test/retest statistics and would give practitioners a starting point for a conversation if the client claims a different result on a retest.
Then, when someone says "last time I took this I got INTJ but this time I got ESFP" (as per Adam Grant and no, I won't dignify him with a link) the practitioner could dig deeper and ask "what made you change your answer to this question?"
That conversation is the kernel of what makes up the MBTI. The questionnaire is just one piece, a "first guess" at the Type code. You need the followup conversation to verify your Type.
The more information a practitioner has for that conversation, the higher the likelihood that a client will be able to verify their Type and reach an understanding of their actual preferences. Then, the next time they take the MBTI, if the Type code result is different, the client will be able to say "Apparently, my mindset is different this time, because I answered the questions differently. I can dig into why that happened and learn more about myself. In any case, I'm confident of my true Type preferences."
* Why do I do this? I hope it's because I care a lot about the MBTI and about the misunderstandings and misinformation that are circulated abut it. Then again, perhaps I'm just a glutton for punishment.
- "The Reliability and Validity of the Myers-Briggs Type Indicator® Instrument" (excerpts adapted from excerpts are adapted from Chapter 7 of Building People, Building Programs, by Drs. Gordon Lawrence and Charles Martin. (link)
- "Myers-Briggs Type Indicator Score Reliability Across: Studies a Meta-Analytic Reliability Generalization Study", by Robert M. Capraro and Mary Margaret Capraro (PDF)
- "Recent Assessments of the Myers-Briggs Type Indicator", Journal of Personality Assessment, by John G. Carlson, Volume 49, Issue 4, 1985 (abstract and PDF (not free))
- "Test-Retest Reliabilities of Continuous Scores on the Myers-Briggs Type Indicator", by Thomas G. Carskadon (abstract)