DISC And MBTI SUCK — Except For One Thing

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- 5 min read

DISC and MBTI are the two most popular personality tools around, even though neither make any sense at all. Rebels, I hope you're not using them. And if you are, why?

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Both have staked a place helping organizations around the world select new hires, help teams to grow together, and allow people to understand each other better. Both are multi-million-dollar industries, with countless workshops and seminars, where people are trained to educate others in this baloney.

Why do they suck?

The scientific community is crystal clear about DISC and MBTI: they predict nothing.

What you want from a personality test (or similar) is a result that tells you about how a person will likely behave in the future. Will he or she fit into your organization, or the job?

Both DISC and MBTI can’t make significant predictions about behavior. Like flipping a coin, or horoscopes, they are occasionally right. But that's more luck than a firm prediction.

Also notable is that the test scores change when done multiple times. A large number of people who do the MBTI-test get totally different results after an interval of 5 weeks That shouldn't happen.

Above all, both are too simplistic. Personality is more diverse and complex than a set of colors (blue, red, yellow, green), or dichotomies (completely extravert or completely introvert).

Why are they still being used, then?

There are many reasons:

  • They are simple and easy to use

DISC and MBTI are easily understood. They are both label-makers. And if we don't have to think hard when using them, that's a benefit. It makes them applicable and translatable to those that need/want to use them.

  • Confirmation Bias

But they are actually pimped-up horoscopes. You can always recognize yourself or another person when using them. It's easy to believe they work. But, like a horoscope, we tend to focus on the parts that fit and align, and ignore those that don't. Everybody can plainly see (and tell) that Fitzgerald the Financier (always hardheaded and busy with numbers) is clearly Blue. And we shouldn't expect Fitzgerald to think about how to treat people in the workplace with love and care. But then we forget Fitzgerald is actually very humane. Take, for example, his volunteer work in a retirement home. With the Blue color, we dangerously oversimplify the much more complex Fitzgerald.

  • The marketing is phenomenal

In stark contrast to real, scientifically validated personality-theories and tests, MBTI and DISC are fed by marketing and business empires that push them brilliantly into view. And the color scheme fits our everyday vocabulary. In the past scientific papers were fabricated to prove their validity. They have been debunked and disproven since. But we still keep believing in them.

  • It feels right

Both tools balance out the positive and the negative in every personality outcome. The negatives make them seem credible (because if everything is positive in a set of personality outcomes, it's bogus). And people feel good about themselves, no matter the outcome. It feels fair when compared to the outcomes of colleagues: they too have the same balance of positives and negatives. True personality doesn't enjoy that luxury. But, it’s not what people want to hear.

What's the one thing that's good about them?

As far as I'm concerned, the one good thing about DISC and MBTI is that they foster interest in, and awareness of, differences between people. And that is a great thing.

But you can do the same thing with theories and constructs that are actually proven, predict behavior, and don't put people in stifling boxes.

DISC and MBTI are like low-resolution photographs. They have lots of pixels and very simplistic resolutions. You haven't a clue what you're looking at when looking at the photograph. But the first photo looks clearly different to the second. That's about it.

What are the alternatives?

The Big Five and HEXACO are both scientifically solid constructs that are great in measuring personality and predicting behavior. The tests are harder to fake (it’s easy with MBTI and DISC), and they both have tons of scientific literature supporting them, which can point out how people will probably vote in the next elections, how susceptible someone is to stress, burnout or some kind of mental disorder. And they predict how someone will likely perform at work. A great number of other implications and findings say something about the behavior of people with a certain set of personality characteristics.

Both the Big Five and HEXACO work with dimensions, which means people can average out right in the middle of Extraversion and Introversion for instance: an Ambivert. Or they can tell that certain people lean towards extraversion, but that at lots of times they will exhibit introverted behavior. This makes for a much higher resolution picture of someone. Goodbye boxes and labels.

Therefore... It's time for HR, recruiters, trainers and others to abandon DISC and MBTI and start using real personality constructs, tests and theories. In the current age of inclusivity and diversity, and avoiding labels, we can't use fake tools anymore.

Fun fact:

Cambridge Analytica used the Big Five (and not DISC or MBTI) to predict the behavior of people so that they could target them better with ads and messaging on Facebook. The aim was that people would be persuaded to believe certain political campaigns, like Brexit. They were quite successful, and probably would not have been if they’d used the other two.

This is a guest post from Lennard Toma, founder of KeytoeY a company to help other companies change into organizations where people enjoy their work. For more information on Lennard and the company, check out his rebel page.

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Replies (26)



I agree. However not with this statement: “A large number of people who do the MBTI-test get totally different results after an interval of 5 weeks That shouldn't happen.”

People are complex and should adapt to changing environments. The outcomes are systemic and thus vary.

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Same to my post

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This article is full of wrong assumptions and reveals a huge lack of scientific rigour in this area. To be brief, it confuses and compares personality tests with personality inventories. The problem with MBTI, DISC or any other personality inventory is not the tool itself, but the massive use of them by people with no training in psychometrics and no certification in the tools. As usual, the problem is not the technology, but the way we use it. And yes, they are simplifications of reality, like any other model.

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MBTI, DISC, PI an similar are Type Indicators. The identify inborn "preferences", which like a preference for creamy peanut butter does not mean you can't/won't each crunchy. Not meant for selection or behavioral prediction. They sort, and the level of preference is also included, so you are never just "one or the other", you have a stronger or weaker preference for one of the dichotomies.
MBTI (in which I am certified) is very clear (in their materials, tools, training) it is not a tool for job/candidate selection.

Big 5, Facet, Chally, Strength Finder and the like are Trait Indicators, which measure the strength enduring behavioral habits that are displayed across a variety of situations and their strength can be measured - usually along a typical bell curve.

I think this post misses the mark in what MBTI, DISC and similar are and should be used for. That said, there are practitioners out there that do not use these tools properly. Feels like you might have watched a Netflix documentary and then wrote a post?

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Either way a test or a “developmental tool” need to provide evidence of its usefulness. In the case of “developmental tools”, two types of evidence are required: (a) construct validity (Is the DISC really measuring “influence”?) and validity based on testing consequences (do these tools help to develop people?). Therefore, their intended use (development) does not waive them from complying with psychometric standards.

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Curtis Michelson

Curtis Michelson

With all due respect to my fellow Rebel colleague Mr. Toma, Big5 is a corporate juggernaut and has woven its way into corporate hiring practices with mixed (some would say quite deleterious) effects, as discussed in HBO's recent doc "Persona" (https://www.hbomax.com/feature/urn:hbo:feature:GYC1puQhu1cLCwgEAAAA0)

The emerging future seems to be a world where algorithms have already surpassed all the prior models, having mapped us and adapted to us with many more data facets than Big5, et al. As those computational tools get better, the prior personality systems will look facile and dull in comparison. AND, we will have entered a Brave New World that SciFi saw coming, but our kids will inhabit, for better and worse.

I see some aspects for the better. For example, Siri already has ability to predict just the music I want at any given time. Stretch that trend further, across all industries, (and deep into the HR suite) and for those who can afford the tools, and toys, this might be quite good and powerful. Automated systems mapping and matching complex people into complex work spaces, forming dynamic teams, and Haier-like micro-enterprises. This could have liberating effects.

(and it could suck)

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