Beware of Misusing Personality Assessments

Years ago I came the closest I've been to leaving the A/E business when I became a finalist for the national sales manager position with the country's largest commercial wildflower seed distributor. Apparently the company was impressed with my business development background, but they expressed concern about my lack of related technical expertise. The other finalist was a botanist who had a limited sales background.

At a follow-up interview, I was asked to take a personality test. A few days later I was told that I didn't get the job because my personality profile indicated I was less suited for sales than the other finalist. That was my first experience with the misuse of personality assessments.

The use of personality testing to screen employment candidates has exploded in recent years, with an estimated 60-70% of candidates being tested. That's up from 30-40% just five years ago, according to a survey by Deloitte. Workplace personality testing has become a $500 million-a-year business and is growing 10-15% annually.

Such growth would suggest that these tests have a proven track record. But that's not the case. Research indicates that personality typing is a poor predictor of job performance or fit. Even the company behind Myers-Briggs, the most popular personality assessment, warns that their test shouldn't be used to screen potential employees. Besides being unproven as a hiring tool, they believe that it's use in this manner is unethical because it's not voluntary.

Myers-Briggs and similar tests have a fundamental flaw: They attempt to lump people into mutually exclusive categories. For example, you are either an introvert or an extrovert. But most people fall somewhere in between (hence the recent term ambivert). The dividing line between the two is arbitrary, as it would be if all of us were categorized as either short or tall.

There are also serious questions about the replicability of the tests. For example, studies have found that retaking the Myers-Briggs assessment as soon as just five weeks later has a 50% chance of reclassifying you as a different personality type. Reproducibility, of course, is a key measure of scientific validity. But the fact is that the science behind these tests is sketchy at best.

Even if personality tests were accurate, the assumption that certain personality types are a better fit for certain jobs is largely a myth. A salesperson, according to conventional wisdom, should be an extrovert—which conveniently excuses most technical professionals from the role since they are predominantly introverted. Except that studies have shown little to no correlation between personality type and sales success. Same is generally true of leaders.

Despite the above criticisms, personality assessments do have their place. They can be useful in helping us recognize our personality tendencies and how they compare with those we work with—assuming they agree to share that information. This awareness can help us significantly improve communication and collaboration.

Identifying employees' personal strengths is also very valuable. Gallup research has found that focusing on developing strengths is a much better way to improve performance than the more common approach of trying to remediate weaknesses. I'm a fan of the StrengthsFinder assessment that came out of the Gallup research. It is used by many of the world's leading companies.

With any of these assessment tools, however, you want to avoid the temptation to oversimplify. I think that's one of the primary reasons personality typing is so popular, because it seems to reduce the complexities of human personality down to a few understandable categories. But such a "paint by the numbers" approach to leadership is naive. People are not so easily pigeon-holed, which makes us both fascinating and sometimes a bit frustrating to figure out.

A shortcut to understanding others would be welcome, but none are really proven.