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Your Favorite Personality Test Is Probably Bogus

Your results may not be as accurate as you think. Here's why.

Hi, I’m Draco Malfoy.

Well, at least according to the Harry Potter Myers-Briggs chart. Ugh! Nobody wants to be a Slytherin. I always fancied myself about equal parts Ginny Weasley and Hermione Granger with a sprinkling of Tonks, so in light of my less-than-flattering results, I took solace in the fact that there are a lot of problems with the Myers-Briggs.

A tale of two tests

Everyone loves a personality test, and the Myers-Briggs Type Indicator (MBTI) is one of the most popular ever created. Developed in 1944 and loosely based on Jungian personality typology, millions have taken this test or one of its many knock-offs and been given a four-letter personality type based on their preferences for navigating the world: either an E for extroversion or an I for introversion, an N for intuiting or an S for sensing, a T for thinking or an F for feeling, and a J for judging or P for perceiving. These combinations result in 16 possible personality types like INTJ and ESFP.

Chances are good that you have either taken this test already or have seen one of its many viral outbreaks on social media. It is ubiquitous in the corporate world; managers use the test for hiring, promotion, and team-building workshops. Outside of the workplace, people share and bond over their results, listicles tout the ideal date idea, best lipstick, best carry-on luggage, and what city you should live in for your MBTI type, and companies like Evernote and Ford even market products and services directly toward different types.

Another test—the Enneagram—has also risen in popularity in the last few years. The Enneagram personality system includes mystical elements and purportedly has ancient origins. It groups participants into 9 types based on the numbers 1-9, with a sub-type, or “wing,” of a different number. The Enneagram has seen a similar marketing trend, especially in evangelical Christian circles after the recent publication of a book that applied the Enneagram to Christian spiritual practice, and a band has even created songs to appeal to each type.

Source: Pexel/rawpixel

It’s hard to swing a proverbial cat and not hit a reference to one of these tests on social media. Should you take them? I’ll be the first to admit it’s fun to use these tests to think about which Harry Potter character you are. However, if you want to learn something about yourself or use the results to make real-life decisions, you may want to reconsider.

Signs of trouble

Several researchers have raised some red flags about the MBTI. One has to do with the theory on which the MBTI is based. Jung developed his theory of personality before the scientific revolution in psychology, and thus it was based on his personal insights without testing whether his ideas about how personality is organized actually mapped onto the universal human experience. Researchers have found evidence against the idea that we tend to be thinkers over feelers, sensates over intuitionists, or judgers over perceivers.

It has several other problems with validity, or accuracy, as well. The scoring format places individuals into one end of each pair—either extroversion or introversion—regardless of how extreme their score. A person who scored as 53% on the introversion-extroversion dimension would have the same result (an E) as someone who scored 95%, but the 53% scorer is probably much more similar to someone who scored just below the 50% mark, earning an I, than they are to their fellow E. And although the test was not developed explicitly for use in the workplace, suggests that the MBTI types are helpful in a variety of work settings and tasks, including leadership development; however, research on its widespread use in this arena has indicated that the MBTI types don’t predict job outcomes very well.

Yet another issue is that the questions on the thinking vs. feeling dimension are scored differently depending on whether you identify as male or female. Finally, many find that it has inadequate test-retest reliability, which means that you might take the test on multiple occasions and receive different personality types, even if you have not changed drastically in real life. Yes, the instrument is widely used, but it is telling that when you look at who uses it, virtually none of them are psychologists.

Although it has received very little research attention, the Enneagram is similar in many ways to the MBTI, which raises some—if not red, then at least yellow—flags about whether it suffers from some of the same problems. Like the Myers-Briggs, the Enneagram’s origin story involves a claim to antiquity and an element of mysticism. Its types have some overlapping content, and in conversations I’ve had, many individuals report feeling like two or more of the types might fit them equally well. I am even one of my own data points; a friend of mine who is very into the Enneagram begged me to tell him which type I was. None of them described me terribly well, but types 1, 3, and 5 were the closest and each contained characteristics I identified with equally.

Personality is more like a spectrum of traits than distinct categories.
Source: Pixabay

Like the MBTI, it is scored in a forced choice format, which asks you to select one option vs. a completely different option for each question rather than measuring how likely you are to endorse each option, which may lead to some of the same problems with reliability and accuracy as the MBTI. For example, a forced choice format might ask, “When I am hungry...” with the options “I eat tacos,” or “I eat cheese.”

As a person who loves tacos and cheese with equal vigor, I must make one of the hardest choices of my life; I must choose either tacos or cheese. If I choose “tacos,” the instrument misses the fact that I also really love cheese. In personality terms, both options in the forced choice format may represent you, and by choosing one and not the other, it changes the type you’ll end up with. Finally, a problem with both scales is that research shows that personality types miss a lot of information; by characterizing someone as an introvert OR an extrovert, we miss a lot of the personal nuances of people who, like most of us, actually land somewhere in the middle.

But wait: There’s a more interesting question

Others have elaborated much more thoroughly and eloquently on the problems with the MBTI than I have here. My goal is not to host a personality test trash-fest, but rather to ask another question that, to me, is far more interesting—if these tests don’t work as well as they say they do, why do they remain so popular, and why do people take their results so deeply to heart?

Some so-called personality tests seem less legitimate on the surface—for example, I never seriously considered that I was an otter or the color red, and I didn’t adopt those things as part of my identity—but my belief that I was really an INTJ was pretty hardcore. As a college freshman, I took the MBTI for the first time and was fascinated by my results. I spent hours on the computer in my dorm room researching my type late into the night, shared it with everyone, and was genuinely proud that my type supposedly represented only 1-2% of the population.

Anecdotally, many people have a similar experience and get very attached to their results. Often, that excitement is because they felt like their results were very accurate, validated something they had already suspected about themselves, or they felt understood for the first time. If you want to see how truly feisty someone is, tell them that their Myers-Briggs or Enneagram results are questionable! How can we believe they are invalid when their results ring so true?

It’s tough to convince people that the MBTI doesn’t reveal deep truths about ourselves. Even when people accept the research on the MBTI’s lack of validity, they may do so grudgingly—they’ll let go, but they don’t have to like it. So why do we still want to believe there is a nugget of truth in our diagnosis as INTJ or an ESFP, a 2 or a 5, even if we acknowledge that those might not be real things?

The answer to that question is complex. Grab a cup of tea and join me for the next post, in which I will explore several factors related to our dogged dedication to bad personality tests: what draws us to personality tests in the first place, how the way results from those tests are presented can influence what we think about them, and how our brains process self-relevant information.