The problem with jerks is that they'll never tell you they're a jerk. Not during the interview process, at least.

It might take a few weeks or months for a jerk to reveal their true colors. By then it's too late. Ideally, you would have never hired them in the first place.

Luis von Ahn has a no-jerks policy. He's the co-founder and CEO of Duolingo, the language learning app. It was named one of Inc.'s best places to work last year.

Brilliance cannot outshine jerkiness.

In the past, Von Ahn has hired jerks. If someone is just super brilliant -- but super jerk-y -- he's made exceptions. But every time, he's regretted that decision. The jerks had to go.

"What I have found over time is that generally, you can find somebody equally as brilliant who's not an asshole," he said on Adam Grant's WorkLife podcast recently.

So Duolingo got serious about keeping jerks out. Through trial and error, Von Ahn figured out how to weed the bad seeds out during the interview process.

Weak links in the interview process

You can try asking a few gotcha questions in an interview -- like a question with no right answer -- but Von Ahn would rather get the information he needs from people who know the potential jerk in question.

He goes straight to their references. Knowing that a candidate has hand-picked references who will sing their praises, Von Ahn asks a simple question: "Do they work well with others?"

Hardly anyone will say no. (Especially if they're trying to get the jerk out of their workplace and into yours.) But if you listen closely to how they reply, Von Ahn says you can very quickly gauge where this person falls on the jerk scale.

Do they work well with others? You want to hear a glowing "Yes!" They're an awesome team player and are great at working with others!

But if you hear any other reply, it's a red flag.

Do they work well with others? "Generally they do," or "Most of the time," or "Yeah, with most people." Hard pass. Those responses means this person is selective in who they will treat well and who they won't. Or that when the going gets tough, they can be a huge pain. In other words, a jerk.

Jerks are costly. Don't hire them.

Even if you really need to make this hire and this person checks all the boxes otherwise, Von Ahn strongly urges that you pass on this candidate. They will end up costing your business more than it's worth. Jerks put strain on other team members, cause drama and impact everyone's productivity.

Hold out for the right person. "In general in a company, it's better to have a hole than an asshole," he says. ?