Ask Erin Mantz why she loves personality tests, and she’ll tell you she’s a Pisces, an only child, and an introvert prone to self-reflection. “I’m constantly craving and searching for insights into why I do what I do, and what makes me tick,” she says. Since discovering them at her college career center, she’s taken many different kinds, but the most transformative was the one she took with her coworkers at AOL in her 30s. A new manager instructed Mantz and her colleagues to take the Myers-Briggs Type Indicator test, which revealed she’s an INFJ: intuitive, enthusiastic, impulsive, and prone to improvisation.

The test changed the whole vibe of the office. “We all shared our results and kept a Post-it on our desk with what everybody’s type was,” Mantz recalls. “Then when Frank called or you needed to present information to Aaron, you’d understand where they were coming from or how to best get through to them.” Some people preferred to hear about potential impact, for example, while others responded best to hard facts. The knowledge has proven useful in her personal life and throughout her career, she says, helping her figure out how to better communicate with others and make the best impression.

Personality tests aren’t new—an early version of the Myers-Briggs test was copyrighted in 1943—but interest in them has endured. People slap their four-letter Myers-Briggs type on their dating profiles and broadcast their Hogwarts House at parties. Many use the results to figure out what career paths might appeal, and some companies use them to decide who to hire.
But why do people like personality tests so much, and which are the most accurate? How should—and shouldn’t—we interpret their results?

Personality tests make you feel seen
Personality tests are a useful way for people to better understand themselves, especially when they’re young, says Brent Roberts, a professor of psychology at the University of Illinois Urbana-Champaign who studies personality development and assessment. “We’re trying to figure out ourselves and why the world reacts to us the way it does,” he says. “I think everybody wants to better know who they are, and where they stand—and that’s what a personality test can give you.”

Ashley Errico, a therapist in Austin, remembers buying All About You! magazine as a pre-teen, drawn to the cover-to-cover personality tests. She and her best friend would listen to the Spice Girls while taking tests to find out what kind of kisser they’d be. Now, in her professional career, she sometimes directs clients to more sophisticated tests, like the Myers-Briggs (which costs about $60 to take online) and Enneagram. (The latter, which costs $20 online, sorts people into one of nine personality types, such as “achiever,” “helper,” or “challenger.”)

Errico has found that the Myers-Briggs test, for example, can supply people who want to change careers or return to the workforce with some ideas that hadn’t been on their radar. There’s a paid service that matches personality type to jobs that might be a fit, and some career counselors are trained to provide feedback. (You can also just Google “jobs for INFJ,” for instance.) “I’ll say, ‘Use those as a starting point, because it might suggest things you’d enjoy but never think about,’” Errico says. Plus, personality tests foster a sense of recognition and belongingness. “Everybody wants to feel understood and seen,” she says. “We all know what it’s like to feel invisible.”

But they really oversimplify things
Personality exists on a spectrum, and no single test can capture all the nuances that define a person. Tests like the Myers-Briggs and Enneagram “aren’t able to describe the richness of human diversity,” says Jaime Lane Derringer, a scientist at the University of Illinois Urbana-Champaign who works at the intersection of personality psychology and molecular genetics.

Take the Myers-Briggs: It distills a person’s traits into 16 different personality types, such as ESFJ (extrovert, loyal) or ENTP (extrovert, imaginative). There are more personality types than that, Derringer says. Plus, the tool frames personalities around positivity—omitting more negative traits, like neuroticism or not being conscientious. “It’s a great marketing machine,” she acknowledges—people love hearing the good parts about themselves—but certainly not comprehensive.

Many personality tests use generic language in their results that could easily apply to whoever is reading it. Scientists call it the Barnum Effect. “It comes from P. T. Barnum saying there’s a sucker born every minute,” says Stephen Benning, a psychology professor at the University of Nevada Las Vegas who studies basic emotional processes. “They’ll basically be able to take this very generic statement about universal human tendencies and somehow think it’s uniquely applicable to them.” That, he jokes, is why there are three things his students can do that make him bang his head on his desk: ask him his Enneagram, his Myers-Briggs type, or his horoscope.

One of the risks associated with personality tests, Roberts believes, “is taking the information too seriously.” These tests are based on self-reported data—it’s up to you to gauge how often you feel angry or excited, and whether you tend to find fault with others. That’s not always accurate. “There are places in our psyche that we’re blind to and might not quite understand,” Roberts says. “Just relying on what you think about yourself is an error, in my estimate.” It’s better to seek out more information from a variety of sources, he says—which could include working with a mental-health professional.

Errico cautions her therapy clients not to over-identify with their results. She’s seen people get too invested in their personality type, which prevents them from allowing themselves to grow and change. Or, they might push themselves into a job that’s not the right fit, because their personality test indicates they should enjoy it. “It’s important to remember that the test doesn’t determine who we are,” she says. “We get to determine who we are.”

Which personality tests are best?
Free online tests that tell you what wild animal or cake you are might be fun, but that’s all they are: entertainment. Some personality tests, however, have been studied for decades, and researchers have a solid sense of their pros and cons. The academic community generally considers tests based on the Big Five to be the most scientifically rigorous. It’s a nearly 75-year-old model developed to measure five broad personality traits—conscientiousness, agreeableness, neuroticism, openness, and extraversion—and lots of free online tests are based on it. “It’s well-replicated across samples, across nations, across time,” Benning says. Taking one of these tests can help people broadly understand their individual differences in personality, and how their tendencies might influence the ways that other people perceive them.

Roberts often directs his students to O*NET, a free U.S. Department of Labor online test that matches users’ interests and level of work experience to potential careers. “It tells you, ‘Here are all the jobs where you’d be more likely to be happy and satisfied,’” he says. “It’s a beautiful tool.” Another free test, the RIASEC model, can similarly help people assess occupation interests. It helps respondents understand if they have, for example, investigative, artistic, social, or enterprising personalities.

Mental health clinicians sometimes administer the Minnesota Multiphasic Personality Inventory (MNPI), says Dr. Rehan Aziz, an associate professor of psychiatry and neurology at the Hackensack Meridian School of Medicine. It consists of nearly 600 true-false questions that can help reveal mental health conditions such as hypochondria, depression, and paranoia. “It’s a very lengthy test, but I found that it gives accurate results,” he says. “It has internal validity measures, which a lot of these personality tests don’t have—which means it can tell if you’re giving inconsistent or inaccurate answers, or if you’re trying to ‘beat the test.’” If you’re interested in learning more about the MNPI, which isn’t available online, bring it up with your psychologist, Aziz advises.

Whichever test you take, consider repeating it every once in a while. Much of Roberts’ research focuses on the ways personality changes over time: Most people shed some of their neuroticism as they age, he notes, and people also tend to get more conscientious as they grow older. “It’s totally useful to come back in a few years and take the test again to see where you’re at,” he says.

And, most importantly, don’t attach too much significance to any personality test-generated label. “None of them are perfect—they’ve all got flaws, and they’ve all got strengths,” Derringer says. “They can’t tell you who you are, but they can provide a framework for you to begin to introspect, and a way to anchor yourself in comparison to other people.”