Personality Tests are Useless (Most Of Them Anyway)


The other day I got an email from a former student of mine. It read:

“Dear, Dr. Burkus, thanks so much for your advice years ago in class on acing the job interview. I’m now at the final stages of the interview process with my dream company and I need to take a personality test. Do you have any advice for acing the personality test and getting the right personality type to get the offer?”

And the advice I had for her was pretty abrupt: Ditch the company.

If they’re assuming a certain personality “type” for certain jobs, then she likely doesn’t want to work there anyway. Her dream job is likely going to become a nightmare.

We use personality tests a lot. And most of them we use for harmless fun like taking a quiz with our friends to find out what Hogwarts House the sorting hat would sort us into. But many people who are taking these tests are taking them quite seriously. Eighty-nine of the Fortune 100 companies subject their people to some form of personality testing at some point in their career.

Somewhere close to 2.5 million people a year take the Myers-Briggs Type Indicator—one of the most popular (and also one of the worst) personality tests out there.

And companies use them for a couple different reasons.

Companies use them often in hiring because we think that we should have certain personality types for certain jobs. Or we think that we need a diversity of personality types on our team.

Or companies use them for team building activities or conflict resolution because we think that if we could just understand the differences in personality between people then we would end up getting along better or working together as a team.

And both of those assumptions are wrong.

Most of personality tests we use are completely useless. Not all of them, but the ones that sort you into a personality type, or letter, or number, are completely meaningless. They’re of dubious origin, dubious methodology, and yet we still use them time and time again. Because there are so many different tests out there, in this article we’re going to limit ourselves to three popular—and largely meaningless—tests.

The Dubious Origins of Testing

Many of the personality type tests that have become so popular have less than scientific origins or are based on scientific ideas that have been disproven.

Consider one of the more popular personality tests in the workplace: the DiSC. The DiSC personality assessment sorts participants by labeling their most present of four behavioral types: dominance, influence, steadiness, and conscientiousness. Although, to be fair to the people at DiSC they would say they are a behavioral assessment. The idea behind the DiSC test started with a lawyer and psychologist named William Marston in the late 1920s.

Marston also did two other really notable things. He was the one that did a lot of the early research in the development of the, now discredited, polygraph test. And he gave us Wonder Woman. (The Wonder Woman thing is actually pretty cool, we won’t hold that one against him.)

Marston theorized that there were basically four different types of people. He believed there were four different ways that people respond in certain situations and used that as his basis for typing them. Then disciples of Marston’s took that theory and developed it into a test to put you into one of these four categories.

Remember that, most of this happened almost 100 years ago. Think about the state of science as a whole, medical science, and especially personality science, 100 years ago. In the time since, every attempt to categorize personality into distinct “types” has failed…even the tests that offered exponentially more types to sort.

The Myers-Briggs Type Indicator (MBTI) does a better job of looking scientific and offers 16 different categories a test-taker can be labelled with. But it is just as dubious in both how it was developed and what it claims to measure. The MBTI started with two women, a mom and a daughter, who basically loved gossiping about their neighbors and other socialites. They had read Carl Jung and loved his idea that there were three basic personality types, but that was the extent of their psychological training. Eventually, they developed a “test” that they could ask people to put them into these different categories based on these different dimensions, though for reasons never fully explained…they added a fourth dimension.

In the decades since, very little peer-reviewed research has been conducted to validate the MBTI. The foundation that owns the rights to the test makes various claims to its scientific reliability and validity, but they very rarely share their data. And when they do it’s mostly inside of journals controlled by the foundation.

One more test that is gaining in popularity and starting to make inroads into the workplace is the Enneagram assessment or the Enneagram of Personality. Now, if you thought that DiSC or the MBTI had dubious origins, then you’ll find this test on another level. The Enneagram sorts people into nine different personality types based on points along an ancient symbol. Those nine personality types were theorized by a South American occultist named Oscar Ichazo who liked to get into hallucinogenic trances by taking Mescaline and Ayahuasca.

(You think I’m making this up but I’m not.)

Ichazo believed that the Archangel Metatron had come to him in a trance and told him that there were nine different personality types. He mapped those nine different personality types along the ancient symbol and, boom, the Enneagram was born. Later, devotees (I don’t know if they did Mescaline or not) would develop a test that would sort people into these nine categories.

By now you get the point. Most of these tests are of incredibly dubious origins and yet we still buy into them. For reasons we’ll talk about in a second.

But in addition to the dubious origins, the methodologies used to develop these tests are also very dubious.

The Dubious Methods of Test Making

Most of the popular personality tests sort you into different personality types, and the way that they do that is basically the same across these tests.

They start with a theory of how many different personality types there are. In the case of the DiSC, it was four types based on four behaviors. In the case of the MBTI, it was 16 based on one of two areas, along four different dimensions. And in the case of the Enneagram, remember it was nine because the Archangel Metatron that told us so.

Once you have your type or categories set, you develop a lot of different questions that you think would help you sort out whether or not somebody belongs in a certain category—in some cases, hundreds of questions. Then you start to give that questionnaire to lots of different people. Having collected their responses, you run a few statistical tests to figure out which questions actually did sort people into those categories and which ones you can eliminate because they don’t add any additional sorting ability.

And you arrive at a much smaller test that you can publish to the world. And you might recognize this process. Because it’s basically the same process a website like BuzzFeed would use to design a quiz that tells you which Saved By The Bellcharacter you are.

The science of personality doesn’t actually work that way. Legitimate personality researchers will tell you that there are no personality types, there are only personality dimensions. And every personality assessment that they developed is designed to show where you exist along a spectrum.

The most well-researched and most rigorous personality assessment is one we often refer to as the Big Five. It offered five different personality dimensions and scored people along a spectrum instead of an either/or type. Those dimensions are Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. In the end, when you take the Big Five, what you arrive at is five scores, that show where your unique personality sits along these five different continuums.

Since the Big Five became popular among legitimate personality researchers, many of the bogus tests added a little bit to their reports to try to look a little bit more like the Big Five. The DiSC now mentions that it’s a “preference” which of these that you are. The MBTI will now give you the results where you exist on the spectrum of four different options, but it saves that information for later in the report. The very first thing you will see is still which of the sixteen categories you fall into. And the Enneagram folks added “wings” to show you that you could be in two

different personality categories. And some Enneagram devotees will even say that all of the nine are represented in everybody but to different degrees. (Which is pretty much an admission that their Sorting Hat isn’t putting people in the right Hogwarts House.)

Why We Believe Bogus Tests

The fact that these bogus tests are trying to make themselves look a little more scientific actually speaks to why we believe them. At least one of the reasons we believe them so much is that they appear rigorous.

The devotees of the DiSC will talk about Marston and his research, as well as all the different variations of DiSC that newer assessment companies have built. And there is a little bit there but not enough to make career decisions or even run a team-building event on.

The owners of the MBTI will talk about their statistical reliability, which despite sounding rigorous only means that the test actually sorts people into the right categories. They’ll never mention, of course, that those categories are basically meaningless and not based on actual personality dimensions.

And while they don’t appeal to science, the Enneagram people will speak to the idea that it’s a 2,000-year-old wisdom tradition passed down from Sufi Mystics—even though the Sufi’s aren’t 2,000-years-old. Or they’ll mention writings of the Christian Desert Fathers—even though those Fathers wrote about what would become the Seven Deadly Sins, not the nine personality types, and none of those Fathers believed in an Archangel named Metatron.

Beyond the appearance of rigor, here’s another reason that we believe these tests. We believe them because we believe the results. Even though, in many cases, the results read like a fortune cookie or a horoscope. For example:

“Tolerant and flexible, quiet observers, until a problem appears, then act quickly to find workable solutions.”

Is that the fortune cookie or is that the description of ISTP from the Myers-Briggs Foundation website?

How about another one:

“Easy going, self-effacing type, receptive, reassuring, agreeable, and complacent.”

Is that a horoscope description of your astrological sign, or is it the description of Type Nine from the Enneagram?

The idea that open-ended, all-encompassing descriptions sound like they are specifically tailored to you (and not written for a broad section of the population) is actually a well-researched phenomenon. It’s known often as the Barnum Effect or the Forer Effect. The idea is that you can appear to be really specific predicting someone’s future or predicting their personality type by being deliberately less specific and giving them a written or a verbal description that is actually so vague it could apply to just about everybody. That’s why some have gone so far as to label these personality tests “horoscopes for nerds.”

Why We Use Bogus Tests

Perhaps here it’s worth stepping back and asking questions about why corporations and leaders even use personality tests in the first place. What are they hoping to learn about their employees, and what are they hoping their employees learn? Predominantly, personality assessments are used in two areas inside organizations: hiring/promotion and team-building.

We use them in hiring or promotion decisions largely based off of the idea that certain personality types or styles lend themselves to certain kinds of work. It’s a faulty idea, but a very tempting one. There is some research showing a correlation between Big Five dimension of Conscientiousness and productivity. But it’s really not that large and not sufficient enough with which to make hiring decisions.

And we use them in conflict resolution because we think that if people can understand each other’s personality, then maybe they would get along better. We think that we would have more empathy for each other if we understood that we’re thinking about or reacting to challenges differently. But there’s not a lot of research that suggests that understanding personality types will lead to less conflict in the workplace. This is partly because most of the conflict on a team or inside an organization is the result of systematic factors like diminished resources or vague descriptions of roles and responsibility. But it’s also because if you are using labels that aren’t real (meaning evidence-based) then people aren’t learning about real differences in personality on their team.

Just finding out that someone is a Sagittarius isn’t all that helpful when you’re trying to get a team to work together.

I know it’s harsh to counsel a student from taking her dream job just because the company wants her to take a personality test. But I also know about the frustrations from so many otherwise talented employees who’ve been subjected to these tests. If her dream company thinks that they’ll make the right decision on a candidate based on personality, or if they believe they can only properly manage her career based on a label produced by a bogus test, then her dream job really will become a nightmare.

Why? Because that company is dreaming.


If you want to learn even more about the future of remote work and how to lead your team from wherever you are, check out my new book Leading From Anywhere at the links below.

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