9 Reasons the Myers-Briggs Personality Test is Trash and Companies Should Never Use it Again
The Myers-Briggs Type Indicator (or the MBTI as it’s commonly called) is an outdated, poorly designed test that has little value. It’s not accurate or useful. There’s also new data emerging that personality tests could be culturally insensitive, sexist, and creating more bias in the workplace. I would argue that it’s dangerous for companies to continue using it. Don’t believe me? Want to cling to your ESTJ? Please read on.
1. The test was not created by experts
The MBTI was the hobby project of a home-schooled aristocrat and is based entirely on her opinions of people. Katherine Briggs read a book about personality by psychologist Carl Jung and her daughter, Isabel Briggs-Myers is largely responsible for creating the test. Neither woman had any training in psychology, test design, or education. Isabel was interested in seeing how personality mapped onto different jobs, but performed no rigorous testing or research into her theory of personality, just finding confirming instances where her test was supported, and eventually selling the test to a large company.
There are countless instruments that are created each year to investigate all sorts of human behavior. These tests are put through rigorous standardization procedures, tested for reliability, validity and put through the peer-review process. The MBTI has undergone none of these. This brings me to the second point.
2. The MBTI is not reliable, or valid
If you’re throwing darts and you always hit the same spot, you are reliable. If you always hit the bullseye, you have validity. If you only hit the bullseye 50 out of 100 times, you might have validity but not much reliability. If you always hit the same spot, but it’s a foot from the dartboard, you have reliability, but no validity.
For a test to be useful, it must be both reliable and valid. You should expect to get the same result every time, no matter where or how you’re taking it. And the test should accurately measure what it claims to be measuring.
The Myers-Briggs type indicator is neither reliable nor valid. Studies have shown that when people take the test multiple times, 50% of the time, their type changes. That’s some suspiciously low reliability. To give you a comparison, the gold-standard IQ test used by educators and psychologists has a reliability score of about 90%
And I know, there are people who are going to argue that they’ve taken this test multiple times over multiple years and always gotten the same score. Folks, this doesn’t mean the test is consistent, it means YOU are consistent.
While reliability is easily mathematically proven, validity is harder to quantify. It’s based on theory. For example, if you take an IQ test, we say we are measuring is your “intelligence”, but there are lots of ways to define intelligence. Personality is no different.
Isabel Briggs-Myers defined personality as four dyadic traits,
Extroversion (E) vs Introversion (I),
Sensing (S) vs Intuition (I),
Thinking (T) vs Feeling (F), and
Judgment (J) vs Perception (P).
Apart from Introversion and Extroversion, these traits are vague and ill-defined. What’s really the difference between “sensing” and “intuition?” Can all of personality fit neatly into these four categories? I don’t think so. And I’m not the only one.
The four MBTI categories aren’t used by professional psychologists at all. These traits are not based on any leading theory of personality, which brings us to the third point…
3. Traits aren’t the best way to think about personality
The MBTI is based on the idea that we have personality traits that are consistent across situations and enduring across the lifespan. But there are many strong alternatives to trait theory.
Many prominent psychologists, including award-winning social psychologist Walter Mischel, have shown that behavior is not predictable across situations and personality is not stable. Mischel argued that personality is much more dynamic.
Meaning, we can’t predict how you will act every time you eat dinner in a group, but we can more accurately predict how you’ll act at a work dinner, vs a family dinner.
Behavior is not predictable across situations and personality is not stable.
Dubbed “situationists”, they argue that a situation is a stronger predictor of how a person will act rather than their personality traits. There’s an interaction, meaning, the situation will influence the personality of the people present, and their personalities will affect the situation.
This is one big reason why using personality tests to predict behavior at work may be problematic.
4. Myers-Briggs chooses for you
Now that we’ve seen a little of the history of the test and where the types came from, let’s take a look at how poorly it’s constructed. As stated above, the 16 personalities come from a combination of four dyadic traits. Unlike more reliable personality tests, which place traits on a spectrum, with the MBTI you are in one category or the other. You are either “Thinking” OR “Feeling” — you can’t be both.
There is an obvious problem with that statement, but I believe there’s an even bigger issue at stake here, and that is that a person who is 51% Feeling is categorized the same as someone who is 99% Feeling. If your answers show you to be even slightly tipped into the Feeling side, you are categorized as such. Now, imagine two people, whose scores look like this:
These two people have similar personalities, but completely different types!
Now, imagine Carl — he’s another ENFP just like Bob, but his scores look like this.
It’s safe to assume that Carl’s personality would look pretty different from Bob's, but they have the same type. In fact, I’d argue that Bob is probably more similar to Jane than Carl.
If you don’t love statistics, you can skip this next section. But if you’re a stats nerd like me, you’ll like this next part.
Even more problematic than the category issue above is the distribution of the categories themselves.
If these personality traits were found among all people, and it made sense to describe them in terms of a scale, you would expect a bimodal distribution.
MBTI traits don’t have this kind of distribution. You would expect to see each of the two categories creating their own individual bell curve, but what researchers have found instead is that most people cluster around the middle, somewhere between the two categories. Most people fall into that gray area like Jane and Bob in the example above. Very few people are strongly one category or the other. Thus the entire concept of type is itself inherently flawed.
5. The statistically slippery Likert scale
That scale that you see on surveys, that asks for “strongly agree” to “strongly disagree” type answers, that’s called a Likert scale. A Likert scale attempts to quantify things that aren’t really quantifiable.
Quantifiable data makes sense in statistics. I know that one pound of dog food is the same weight as one pound of lemons. I can use these numbers to compare and calculate differences. I can calculate an average, and it’s meaningful.
Likert scale data is categorical. Agree and disagree are categories. For example, let’s say I have three categories for hair color; brunette (1) blonde (2), and red (3). Out of the 100 people I interview, there are 52 brunettes, 36 blondes, and 12 redheads. In this context, it makes absolutely no sense to say that the “average” hair color of people is 1.6. But, if I assessed everyone based on a hair color spectrum, where the lightest hair color was 1 and the darkest was 10, and there was a clear scale based on this variable, then I could say that average hair color was a 7, and it would be meaningful.
This is where Likert scales run into huge problems. It’s treated like a spectrum, where each number on the scale is equidistant from the next, but the reality is quite the opposite. The difference between a 4 and 5 is not necessarily the same as the difference between a 1 and a 2. And my 4 is not the same as your 4. If I start calculating analyses on these answers, I’m committing a big cardinal sin in statistics, which is to treat categorical data like it’s quantitative. Technically, this should never be done.
Also, your personality will affect how you answer the questions. This strikes me as such a hilarious level of irony that it might deserve its own bullet in this list. Extroverts are more likely to pick 1s and 5s when they answer questions, and introverts are more likely to pick 3s. Think about it, if you have someone who’s bold and opinionated they are going to be fine with circling strongly agree/strongly disagree with everything. They know their opinions and love to share them. But if you are more cautious, more thoughtful, you might find yourself hesitating or over-thinking your answers, and choosing the neutral response. And is this taken into consideration during scoring? Absolutely not.
6. We are all liars
If you gave the MBTI to your mom, your best friend, and your romantic partner, and asked them each to take the test for you, what would the outcome be? Do you think that each one would have the same result? I bet not. So which one is the “real you?” (hint — they all are)
The MBTI, and most personality tests are “self-report”- you are answering questions about yourself. How good are self-report tests at giving us information? The assumption is that you know how you might behave in a certain situation, but I’d argue that your answers reflect how you’d LIKE to behave in a certain situation. Whether or not you’d actually do it is a totally different story.
A few years ago a study about lying got a lot of press. It showed that during a 10-minute conversation, 60% of people told at least one lie, and some told two or three. Basically, the subjects were lying to make themselves look good.
People lie on their dating profiles, on their social media, and they lie in conversations with their families more than with their friends. In general, we can’t be trusted. And we REALLY can’t be trusted when it comes to things that make us look good or bad. If it’s a fact that might increase your social status, you’re willing to massage the truth a little.
Clearly during a self-report measure of personality, when you are being asked questions that make you look good, you are going to push the needle a little. We all will. But, this renders the test totally useless.
7. The Lake Wobegon Effect
People love their INFJ’s and ENTP’s. You see them on dating profiles, social media posts, memes. Some people really identify with their type. This is because they are using a confirmation bias, meaning the test confirms what they already thought about themselves. But then, of course it did, right? The only person the test asked was them.
Because the MBTI is a self-report test, just about the only thing it IS a good indicator of is what you value and think is important. As illustrated above, the way that people answer questions on the MBTI is aspirational. We are going to underestimate the bad and overestimate the good. It’s just human nature to do this. But, what we choose to overestimate depends largely on what we value. For example, if you think empathy is really important, you will likely answer any question regarding empathy with a little more care and thoughtfulness than say, organization.
Ask yourself this question: compared to other people, how generous are you? Would you say you are about average, above average, or below average?
The truth of how generous you are compared to everyone else is unknown to you. Just like any human behavior, generosity falls into a normal distribution, some people on either extreme and most people clustering in the middle.
If you think generosity is important, you probably think you’re above average. This is a psychological phenomenon called illusory superiority. When it comes to good qualities, like generosity, kindness, honesty, people tend to think that they’re above average, and on unpleasant traits, they’re below.
We can objectively measure generosity. Let’s say we created a scale, looking at the amount of money you give to charity, how much you spend on gifts, how often you volunteer your time, let someone in front of you in traffic, or have your seat on the bus. If we were to quantify these things and give everyone a number, where you fall on this distribution may end up being pretty different than your self-report. If I just ask you — “how generous are you?” most of us would answer that we are above average.
But we can’t all be above average, can we?
8. There are no bad personality traits
In my introductory psychology class, I always have my students take multiple different personality tests and compare them. One of these tests is the Enneagram. It’s also not well supported by research, but I love using it for one reason — it will tell you the negatives about your personality as well as the good stuff. The Enneagram will place you into one of nine categories, and the description of your category will include all the annoying crap that you do when you are not at your best.
My students inevitably hate this test! No one wants to hear bad things about themselves. They all love the MBTI and said it sounded “more like them” (even though in general, the results are similar).
And this is one of the main reasons the MBTI is so popular, no matter what category you get, they are all good. They all have very positive descriptions and there are virtually no negative personality traits. How can this be? I challenge you to do an informal poll of your friends and ask them if they think there are any negative personality traits. I’m sure 100% of them will say yes. Ask them if they have any of these negative traits and they’ll likely say yes to that too.
How can a comprehensive test of personality have no ability to predict if you are annoying? Because it’s set up that way. It’s affirming and complimentary and thus people love it.
9. Personality tests in the workplace are limiting and dangerous
According to the Myers-Briggs Company, the huge company responsible for peddling the MBTI, it is used by more than 88% of Fortune 500 companies in 115 countries, and available in 29 languages. For a test with no predictive value, this is incredibly troubling.
And yes, you heard right, the MBTI has no predictive value.
There is no scientific evidence to show that this test will predict whether someone will perform better in a particular job, have more job satisfaction, or be more likely to stay in that job. When independent analyses are calculated looking at personality types and jobs, there’s no more correlation than when looking at a random sample of the population. In other words, there’s no greater number of any one personality type in any job at all.
So why do companies use this test if it’s essentially as predictive as a Buzzfeed astrology quiz? One answer may be the incredible amount of money the company spends marketing its test. Rather than going through the usual vetting process of standardization and peer-review, Isabel Myers-Briggs eagerly sold her test to a company to begin marketing and selling it right away.
It has been on the market since 1975. Companies love to streamline messy things like human behavior, and buying a test that purports to make hiring and placement easier is very seductive. But we can do better. Create tests that are specific to your company. Come up with real-life scenarios and ask employees or interviewees how they would handle them. If you want to know if someone is a team player, do a group interview and watch how folks interact. Give them exercises that challenge them and see what they do.
Don’t ask how they think they would do in a hypothetical situation on paper, test how they actually do when put into that situation.
I recognize that there are still going to be people who read this and insist, “but I just like it” and they will refuse to see that the only reason the test makes them feel good is that it confirms what they already think, and only shows them the good stuff.
You could just as easily write a short essay about your personality and why it’s awesome and it would be just as meaningful as the MBTI.
And when you see the career suggestions at the end of the test, remember that they are as accurate as a fortune cookie in predicting whether you will excel at that job, or enjoy it.
Personality tests are relatively harmless when taken for fun, as long as they are taken with a clear understanding that they are not that accurate. But I’d argue that using them in the workplace is unfair, and in fact, could be downright harmful if they keep someone from getting a job they desire or deserve.