But Harry Nelis, who has been a general partner at Accel’s Europe office since 2004, knows this isn’t enough. Alongside academic prowess or proven success as an entrepreneur, he expects his future colleagues, armed with a $650 million purse, to have the right kind of appetite for risky bets.

Accel, the American-based fund has an admirable track record of successful startup bets. The group appeared early in the rise of multibillion-dollar companies including Facebook, Spotify, and Monzo. The fund’s employees are Ivy League and Oxbridge grads, former successful founders, and PhDs working on cutting-edge technologies that might create massive opportunities in the future. 

But when Nelis sits down to interview these prospective employees, there’s one mystery in particular he’s keen to decipher.

“What’s the riskiest thing that you’ve ever done in your life?” Nelis asks job candidates vying for a position at Accel.

His own answer? Getting married.

In an interview at Accel’s London offices, Nelis reassured Fortune that he has been happily married for 30 years. His question, though, speaks to a core tenet of his job.

“The hardest thing is to live with the knowledge that very likely you can be wrong,” Nelis told Fortune from Accel’s London office. “The biggest mistake in venture is not losing money on an investment. It is missing the outlier.”

Nelis’s question can reveal the character of his future employees. Perhaps more importantly, though, it gets to the heart of the mindset of investors working in venture capital.

VC funds work almost exclusively in the business of “moonshots,” making bold bets on a heap of companies in the hope a few will break through and provide a return on investment for a whole funding round. 

Unfortunately, that means most companies that gain financial backing will fail. By a range of estimates, it’s between 75% and 94% of startups that don’t make it to unicorn status. The odds aren’t much better than they are in gambling.

Nelis has witnessed the evolution of Europe’s startup scene since he began overseeing Accel’s London office in 2004. The group was an early backer of Spotify, replicating its success across the Atlantic as an early investor in Facebook. In Europe, the process of identifying new founders has become much more common since those early funding rounds.

According to a new report launched by Accel and Dealroom, employees of European unicorns have gone on to found 1,650 startups across Europe between 2008 and 2025. 

Fortune spoke with several founders who have emerged out of this ecosystem over the last two decades, beginning with Skype’s rise to one of Europe’s first unicorns.

Read more from Fortune

Nelis says the idea of failure can be a hard concept for junior candidates to grasp, given they have made it to an interview with Nelis thanks to a track record of success. 

“Typically, people who have done well in school and done well in their careers, they don’t like getting it wrong. But in our business, you need to get it wrong a few times to get it right. And that’s what we look for in investors.”

At the same time, Nelis expects candidates to know why they’re taking a risk, rather than fumbling into it. He recounted how one candidate shared their story of getting lost while hiking, something Nelis regarded as the wrong answer.

“You didn’t think about the risk that you took. You kind of just stumbled into the thing that would be dangerous and stupid. That’s not proactive risk-taking,” said Nelis.

“Risk-taking is about, ‘what do I get when it goes well?’ And is there a path where it can go well? Because sometimes there’s no scenario in which it goes well enough to compensate you for all the risks that you’re taking.”