The One Interview Question You Should Always Ask, but No One Ever Does

You’re interviewing someone for a key position and you like what you see. Based on this person’s experience, demeanor, and the conversations you’ve had so far, he or she seems like a perfect fit for the job and your company.

On the other hand, you know that eager job applicants do everything they possibly can to make a good impression when applying for a job. Wouldn’t it be great if there was a simple way you could find out the things about their personalities and job histories that they aren’t so proud of?

There is. Ask for negative references.

That advice comes from Bart Lorang, CEO of cloud-based contact management company FullContact. He first asked this question while interviewing a strong job candidate named Mike for a sales executive position. The two were talking over a couple of beers and the conversation turned to people from their past who would love to work with them again–and those who would hate to. Out of the blue, Lorang asked, “Would you trust me to talk to some of those people?” To even things out he also gave Mike the names of some former colleagues who would have uncomplimentary things to say about him.

Talking to Mike’s negative references was so revealing–and made Lorang so sure that Mike would be an asset to FullContact–that he now incorporates this step into the interview process for every important position.

Here’s how Lorang makes it work–and why you should try it too:

1. Begin by building trust.

Only ask for negative references (or positive ones for that matter) from candidates you’re seriously considering as hires. “You don’t do it on day one,” Lorang says. “Build some trust first and show some vulnerability yourself.” You can do this by talking about your own mistakes and what you’ve learned from them, he says. Once you’ve established that connection, and made it clear that you’re not perfect and you don’t expect anyone else to be either, ask the candidate for negative references. Lorang usually asks for at least three.

2. Give them time to think about it.

Most people will be taken aback by the request, and may not be able to supply negative references right away, Lorang says. “They have to process it and think about who they would give for a day or so.”

“A few people have said they don’t have any negative references, and I think, ‘OK, I’ll go find them,'” Lorang says. “We always do off-sheet references.” In fact, he takes a complete lack of negative references as a bad sign, not a good one. “There are no negative references in your whole career? You’re that likeable? If you’re so universally well-liked, you’re probably not pushing the envelope hard enough.”

3. Call the negative references and get them talking.

This will be easier said than done. “When I first started calling negative references, it was fascinating,” Lorang says. “I felt like some phone salesperson trying not to get people on the other end to hang up.”

Some people were a bit annoyed to be listed as a negative reference. “To be called out as a person who hates someone else–people react a little defensively to that,” Lorang says. He also had to get past people’s understandable caution. “We’re all taught not to give negative references.”

Once you get people talking, though, the responses they give will tell you a lot, both about the job candidate and the person doing the talking, he says. In Mike’s case, some of the negative references were salespeople who had been achieving their quotas but he fired them anyway. “In sales that’s unusual and it generally happens because the person is a prima donna who is bringing down the performance of the whole team,” Lorang says. “That taught me a lot about the type of person Mike was.”

4. Present your findings to the candidate.

When you talk to the negative references, Lorang advises, listen carefully for the facts. “You’re trying to remove the emotion from what happened,” he says. “There’s going to be a lot of bluster. You’re trying to find out what was the series of events that happened and why did the person respond the way they did?”

Once you’ve gathered information from the negative references, schedule another meeting with the candidate where you will present those facts as unemotionally as you can. “I say, ‘I told you I was going to come back to your with this data,’–I always call it data,” he says. “‘What’s your reaction?'” Lorang says he asks the question that way to give the candidate the freedom to say what their emotions are about what they’ve heard.

Candidates’ responses are extremely revealing–probably more so than the actual information he’s received. “A lot of times these negative references are years old, and with time comes a lot of rationality and perspective,” he says. Many candidates are able to acknowledge the errors of the past or consider how they might have handled a difficult situation differently.

If they get defensive, that’s a red flag. “Some people have the desire to blame others for what happened or an inability to accept their part in it,” he says.

“I say, ‘Let’s talk this through. What did you learn from it?'” he adds. “I’ve committed multiple sins against my fellow man–it’s how you own it that matters. It’s a journey we’re on, and we all can improve as humans. If someone’s not introspective, and not a lifelong learner, then I don’t want that person on my team.”

This article was originally published at inc.com.