Standardized testing isn’t something you escape once you’re out of high school. For 89% of Fortune 100 companies using the Myers-Briggs Type Indicator Test (MBTI), it’s still a method to gauge an employee’s potential. To date, over 50 million people have taken a test that includes 93 questions that peg users in one of five personality types. MBTI is based on Carl Jung’s theories on psychological types and is geared toward measuring psychological preferences in how people perceive and navigate through their world. The problem is that Jung’s theories were developed in the 1920s, while the MBTI was first developed during World War II. Meanwhile, for over three decades corporations have been almost exclusively relying on this method of testing. Today’s world is vastly different from the one that molded a personality and shaped a work environment nearly a century ago. What worked then might not work now simply because both people and environments are rapidly shifting, meaning that an MBTI assessment cannot adapt to reflect new needs.

Wharton professor and author of Give and Take, Adam Grant, would agree that it’s time to say goodbye to the MBTI. Initially an introverted “INTJ” type, Grant took the same test a few months later to find he was now an extroverted “ESFP”. While there isn’t necessarily ‘right’ personality type, employers are looking for what’s labeled as the Big 5 traits (extraversion, emotional stability, agreeableness, conscientiousness, and openness) that in the past have produced winning employees. Curious about variations between his two results, Grant discovered that the MBTI has an accuracy rate somewhere between a polygraph and a horoscope reading. Grant’s recommendation is not to rely on the MBTI exclusively but to use it as a guide toward a greater conversation about personality types. There are a couple reasons for this aside from the shaky readings.

In Dan Pink’s work, To Sell is Human, Grant also discovered that “most people are ‘neither overly extraverted nor wildly introverted.’” Herein lays a fundamental marketing problem with MBTI. As Grant points out, since “most people prefer to be called agreeable than disagreeable,” the test wording should “repackage this trait as supportive versus challenging.” Factors as basic as language sway answers one way or the other, which once again highlights a test that cannot keep up with shifting trends.

Furthermore, peg people into one box or another is a mistaken move and a direct result of a test that doesn’t, on top of many other things, account for personality variations. For example, MBTI accommodate a more recently developed personality type, and that’s the “honest-humility” type as supported by the HEXACO personality model (leading new thinkers to round off to six personality types versus Myers-Briggs’ five).

So why do more than “10,000 companies, 2500 colleges and universities and 200 government agencies in the United States use the test”? Perhaps it comes down to good old fashioned habit. It’s a standard of measurement and one that has yet to be replaced with something equally calculable. Here Grant turns to Annie Murphy Paul, the author of The Cult of Personality: How Personality Tests are Leading Us to Educate Our Children, Mismanage Our Companies, and Misunderstand Ourselves, who suggests it could be a simple matter of commitment. Countless dollars and man-hours have been invested into this system; it’s too convenient to let go of. Grant also alludes to personality psychologist Brian Little who suggests that personality types indulge an ego that favors identification.

Perhaps the answer isn’t saying good-bye completely, but being advanced enough to recognize the Myers-Brigg test shouldn’t seal an employee’s fate nor be an iron-clad marker for their potential.