Google legend Eric Schmidt said successful people all have grit as a personality trait. Scientists say he might be misguided.

• Successful people have grit, former Google CEO Eric Schmidt told CNBC.
• Grit — a mixture of passion and perseverance — was coined by psychologist Angela Duckworth in 2013.

What makes a person successful? Eric Schmidt, the billionaire and former Google CEO, thinks he knows.

"The most successful people have a lot of skill," Schmidt told CNBC Make It. "They also have grit. In other words, they're willing to put up with the setbacks and the inevitable challenges that people deal with in their own lives."

Schmidt became Google's CEO in 2001. He stepped down in 2011, and was executive chairman, then technical advisor at parent company Alphabet until 2019, before leaving to focus on philanthropic and investment house Schmidt Futures.

With a fortune of $26.3 billion, he's the 51st richest person in the world, according to Bloomberg's Billionaires Index, although his close ties with the Obama and Biden administrations have drawn criticism.

Speaking more broadly about ambition, Schmidt said he'd always desired a "seat at the table," even if he didn't understand that goal at the time. "I just thought it was really interesting what we were working on," he said. "Anybody who is a workaholic has this notion that you're missing out — you have FOMO."

Since being coined by University of Pennsylvania psychology professor Angela Duckworth after her pivotal study of West Point Academy Graduates — and subsequent 2016 book — the psychological trait known as grit is often put forward as a key tenant behind success.

Grit is essentially a mixture of passion and perseverance in the pursuit of long-term goals. "Gritty" people stick to their guns and are unperturbed by any obstacles or hardships they may encounter.

The concept has been so influential — and was even adopted in some schools — because it essentially proposes that talent, and IQ come second to dedication, and that achievement is reachable through hard work.

But over time, scientists began to question the concept, arguing that it's too simplistic and doesn't take into account social, economic, and emotional factors, which impact people's opportunities and career paths.

Our environment and resources we're given access to matter

One study found that grit has little impact on the academic performance of students deemed to have lower levels of IQ. Others suggest there's a correlation between the quality of schools attended by a student and the level of perceived support offered by an employer and grit.

In the latter, US academics who were deemed highly gritty made less progress towards their work goals if they felt neglected by their employer, and vice versa.

Whether the idea of grit is even applicable to most standard career paths is also questionable. Simply working hard on one thing is no guarantee of a swift climb up the corporate ladder. Other personality traits, including agreeableness, adaptability, and conscientiousness, as another study found, are just as important, if not more so.

Put simply, grit is often misunderstood

Duckworth herself maintains that the idea of grit is often misunderstood, with many examples often leaning too heavily on the idea of perseverance. Endeavor matters but it's just as important for a person to have a direction that they're passionate about, she told Melissa Dahl at the Science of Us.

Her own follow-up paper, a 10-year study of 10,000 West Point graduates, found that the most significant indicator of physical performance was physical ability.

Finding one singular driving passion can often be a long and messy process. Instead, people should "explore their many interests and values," as a starting point to achieving their goals, Duckworth told The Harvard Crimson, in April 2022.

That doesn't mean that the notion of grit is without value

Grit helps us to break down the idea that some people simply possess superhuman talents. It helps to cultivate the idea that "success" in whatever field, rarely comes without setbacks and discomfort. But there are other factors at play.

"Luck of birth, education, interest, timing, and the business I was in," Schmidt told CNBC. "I also worked hard, but luck is just as important, if not more important, and as you get luckier, you create your own luck."