Want to know a secret? Personality tests in the workplace are overrated.

Data backs up this idea. According to a study by Michigan State professor Frederick Morgeson, “there was a near zero correlation between personality tests and job success rates- 0.03 to 0.15.” Research shows that personality tests just aren’t very good at predicting workplace success.

There’s a stunning amount of laziness from companies who use these tests as the primary way to evaluate employees. Here are several practical reasons that illustrate why these tests aren’t effectual.

Applicants Don’t Give the Right Answers

One of the major problems with personality tests is that employees don’t give truthful answers. Employees tell employers what they want to hear because they fear they’ll be discriminated against otherwise. This perhaps happens nowhere more than the introvert/extrovert questions. Peruse this quote from the Hoffeld Group, “traditional sales wisdom claims the best salespeople are extroverts.” The idea is that extroverts are better in managerial positions and sales positions. If an employee feels like they may be removed from consideration because of their personality, then some of them will lie on the test. All of them won’t, of course, but some will.

This problem is compounded by the fact that it’s relatively easy for employees to answer in the way employers prefer. Timothy Horrigan from La Weekly says, “In theory, you can design personality tests to detect cheaters. But most tests aren’t sophisticated enough to do so reliably.” This leads to an excess of bad data, and you know what statisticians say about bad data- garbage in, garbage out.

Personality Tests Promote a Lack of Diversity

Another problem with personality tests is that when they do work, they limit personality diversity in the workplace. Take a look at the four sections of the Myers-Briggs: introvert/extrovert, intuitive/sensing, thinking/feeling, judging/perceiving. The point of the test is that certain characteristics are desirable for a position, and other characteristics are undesirable. For instance, you may believe you want “thinkers” in your engineering job, or “sensors” as park rangers.

However, there are some problems with this approach. The elephant in the room is that prominent stars constantly rise to success despite having the “wrong” personality. For example, you would think a CEO needs to be extroverted, but there are plenty of success stories that prove otherwise: Bill Gates, Marissa Mayer, Warren Buffett, Guy Kawasaki, Mark Zuckerberg, and many others. These people have to meet-and-greet almost every day of their lives. They don’t just do it; they excel. However, it doesn’t mean they eventually changed into extroverts.

Guy Kawasaki said on Twitter,

“You may find this hard to believe, but I am an introvert. I have a ‘role’ to play, but I’m fundamentally a loner.”

If someone loves their career, they can embrace (and excel) at aspects of it they don’t have a natural aptitude for. There’s another rumination here too. People who master abilities that don’t come naturally to them have an alternative perspective on these abilities. An unusual perspective may make it easier to teach, perform, or even enhance the aforementioned skill. This is why diversity is so important in the workplace.

The Financial Cost of Personality Tests

Personality tests have a laundry list of problems, but one of their most practical concerns is their cost. Of course, there are free personality tests online. Yet, the problem is quality. The previously mentioned LA Weekly article by Timothy Horrigan notes that test-taking is a game of lying by test-taker and counter-detection efforts by the test-issuer. Using free tests to screen candidates is like pitching to the opposing baseball team with your non-dominant hand. You’re at an extreme disadvantage, and it’s unlikely you’ll get the results that you want. As a result, employers often pay for personality tests. These examinations aren’t cheap.

According to Career Trend, the typical test costs anywhere from $100 to $5,000 per person. There’s a lot of variation in those numbers. Obviously, the more expensive the test, the more accurate it should be, and the better the measures are against cheaters. However, $5,000 is a lot of capital- unless you’re Apple or something. Imagine paying this, not for every candidate that you hire, but for every candidate you interview. That would get expensive fairly quickly. Even a number toward the lower-end of the spectrum, say $1,000, is stretching a point for many businesses. Also, the less you spend, the less confidence you have in the test.

Of course, this helps explain why companies put significant stock in personality tests. They have a significant financial cost. If you are spending big money on the tests, then you certainly want to them to influence your hiring decisions. Otherwise, why would you spend money on them in the first place? This is the catch-22 of using personality tests for hiring.

Final Thoughts About Personality Tests in the Workplace

The idea of personality tests not working for business owners is incredibly counterintuitive. You’d think they would work well. Tests are an important way of examining people for work and school. Students must take the SAT to get into college, and lawyers must pass the bar exam to obtain their license. It was once thought a personality test, even though it is a subjective exam, could be as robust as these other tests, examining employees with machine-like accuracy. Although personality tests have minor uses, they’ve never come close to that lofty billing.

Do you agree? Share your thoughts about personality tests in the comments below.