While competent, hard-working employees may be the most qualified for the job, they’re not always the ones getting promoted. In fact, studies show narcissists are more likely to be given leadership positions.

There’s a good chance you’ve encountered this at one time or another. Perhaps you’ve witnessed a colleague work his way up the corporate ladder by bragging about himself. Or maybe you’ve worked under a boss who fired anyone at the first hint of dissension.

Whether it’s a CEO or politician, narcissists often rise to the top. But research shows narcissists aren’t necessarily good leaders. They’re just skilled at convincing people they can handle the job.

Why Narcissists Are More Likely to Get Promoted

Studies show narcissists exaggerate their skills. And they convince people they can handle anything that comes their way. From a disloyal employee to a financial crisis, they claim to have it covered.

Quite often, their arrogance comes across as confidence. And people tend to like leaders who are sure of themselves.

Narcissists are also charming. Initially, people view them as likable and qualified. And their charisma helps them work their way up the ranks with relative ease.

One reason narcissists come across so self-assured is that they truly believe they are superior. Studies show narcissistic CEOs are so convinced of their own vision, they convince other people to follow them.

And the more followers a leader has, the more likely people are to assume he’s a good leader.

Are Narcissists Good Leaders?

Narcissism has been a hot topic in psychology for the past decade. And many researchers have examined how narcissists perform in leadership positions. The results vary, depending on how the research was conducted.

When asked to evaluate their own performance, narcissists rate themselves as excellent leaders. But, their subordinates and their supervisors tend to rate them as poor leaders.

In 2014, researchers from the University of Illinois decided to examine all of the studies to gain a more definitive answer about whether narcissists make good leaders. They concluded there was no direct relationship between narcissism and leadership success.

The study also highlights the fact that people aren’t either total narcissists or complete non-narcissists. Narcissism is on a spectrum and each individual embodies narcissism to a certain degree.

And researchers discovered that bosses with extremely low levels of narcissism were poor leaders too–just like those with high levels of narcissism. Leaders who lacked narcissism were viewed as insecure.

But those on the opposite end of the spectrum–with too much narcissism–tended to be aggressive and tyrannical.

People who made the best leaders displayed moderate levels of narcissism.

Narcissistic Leaders Do Outshine Others Sometimes

In the midst of an organizational crisis, a narcissistic leader is most likely to thrive. Their eagerness to take bold moves, combined with their ability to sound sure of themselves, can help anxious people feel at ease.

But, when things are stable, narcissists tend to be less effective. Their arrogance may grow tiring and their bold moves may rattle employees who value job security over constant change.

What Hiring Managers and Leadership Teams Should Know

Although it may be tempting to promote the person who says she has the power to lead a team to victory, those words may be nothing more than lip service. Just because someone says she knows how to lead–and she sounds self-assured when she says it–doesn’t mean she has the skills to back up her claims.

Hiring managers and leadership teams should remember that narcissists are likable at first. But eventually, they wear out their welcome and may do more harm than good.

The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.