Getting up early, wearing the same clothes every day, eating eggs for breakfast… there are various thing we’re told CEOs do that may hold the keys to their success.

But what if the one thing the most successful have in common is in fact not something they do but the way they are?

The results of a new study certainly suggest this is the case. And the shared attribute? Introversion.

Researchers from ghSmart, a Chicago-based consultancy firm, spent ten years analysing the personalities of 2,000 CEOs and reached the conclusion that the majority of the successful ones were introverts.

This flies in the face of the image most people have of a typical charismatic, confident, extroverted leader.

The study, called the CEO Genome Project, includes a test anyone can do to find out whether they have what it takes to be a CEO.

“When we flip on the news, or check our social media feeds, we are bombarded with images of well-groomed, Ivy league-educated icons of the Fortune 100,” the study authors write. “And we can’t help but think, I could never be them.

“In fact, they come from surprisingly varied backgrounds. Of the six million CEOs of companies in America, only seven per cent went to an elite school—and eight per cent didn't graduate college at all. Some are immigrants; many worked their way up through the ranks from entry-level positions.”

10 people who prove you don't need good grades to be successful Show all 10 1 /10 10 people who prove you don't need good grades to be successful 10 people who prove you don't need good grades to be successful Clare Balding Clare Balding OBE is one of the country’s most prolific broadcasters, turning out for BBC Sport and Channel 4 amongst others. She recalled her wayward youth for The Independent, where she was at one point suspended for shoplifting, and was initially spurned in her Oxbridge ambitions following mixed A-level results. After two years out, Balding retook exams and spruced up her interview technique to gain entrance to study English at Cambridge. Getty 10 people who prove you don't need good grades to be successful Benedict Cumberbatch The Harrow educated actor admits he had a pretty good start in life, but claims “pot, girls and all sorts of other things” contributed to less-than-stellar GCSE and A-Level results, however. It was not until university that he pulled himself up by his brogue-straps and took his academics seriously. Getty 10 people who prove you don't need good grades to be successful J.K. Rowling The author was by no means a bad student — she was Head Girl and left school with two As and a B before going on to study at the University of Exeter. However, her rejection from Oxford University nevertheless goes to show how slim the margins of success can be in higher education. Getty Images 10 people who prove you don't need good grades to be successful Jeremy Clarkson A figure of fun and derision he may now be for many, the defunct Top Gear presenter began his career in journalism and entertainment with very little formal education to his name. Expelled from Repton School for “drinking, smoking generally making a nuisance of himself”, he began writing for local publications such as the Rochdale Observer and Shropshire Star before eventually becoming one of most recognisable faces in UK show business. BBC 10 people who prove you don't need good grades to be successful Simon Cowell The X-factor villain left school with only one O level to his name, before re-enrolling at Windsor Technical College where he gained another. This background did not naturally lead to the heights of the entertainment industry he would eventually reach and at EMI Music, where he began his career in music, Cowell started off with a job in the mail room. ITV screen shot 10 people who prove you don't need good grades to be successful Alan Johnson MP The former Education, Health and Home Secretary and current Member of Parliament for Hull West and Hessle is living proof that those disenfranchised at a young age and denied the educational pedigree that usually accompanies a career in politics can succeed in this field nevertheless. In his memoirs, Johnson describes a bereft childhood, made an orphan at 12 before leaving school with scant qualifications, drifting between jobs as a Tesco shelf-stacker and postman. He went on to become a leading union figure before ascending the ranks of the Labour party. Press Association 10 people who prove you don't need good grades to be successful Sarah Millican Now one of the country’s most successful comedians, Sarah Millican admitted she got two Ds and an E at A-Level. "To A-level students getting their results today: much luck to you," she once tweeted, “but if you don’t get what you need, it isn’t the end of the world: You can always resit.” Tim P. Whitby/Getty Images 10 people who prove you don't need good grades to be successful Bill Gates Probably the epitome of the college-dropouts-done-good crowd, Gates took his leave of Harvard College to pursue his aspirations in computer software. Admittedly his aptitude for computers had singled him out from a young age, and not every young entrepreneur is a software genius, Gates still shows the path to success need to be as rigid as it may seem. AFP 10 people who prove you don't need good grades to be successful Steve Jobs Without a doubt one of the great innovators of our time, college became an expensive luxury for the adoptive son of a mechanic and he dropped out long before graduating. Instead he drew his inspiration from other places and aspired to do something that stood “at the intersection of humanities and sciences”, also crediting the 7-months spent in India after leaving Reed College as an important formative experience for him. Justin Sullivan/Getty Images 10 people who prove you don't need good grades to be successful Mark Zuckerberg The Social Network made many of us familiar with both Zuckerberg’s innovative genius as well as his ruthless business dealings. Although Facebook at its inception was meant to be just a “Harvard thing”, it soon grew beyond this and Zuckerberg dropped out from college to continue expanding it. AP

To reach their conclusions, the researchers made a database of assessments, including comprehensive performance appraisals and extensive biographical information, which documented everything from behavioural patterns and demographic information to career history and previous job performance.

From these findings, they were able to work out who amongst us are most likely to become a CEO.

They found that the four most important traits for CEOs are:

Reaching out to stakeholders Being highly adaptable to change Being reliable and predictable rather than showing exceptional, and perhaps not repeatable, performance Making fast decisions with conviction, if not necessarily perfect ones.

About half of the candidates had at least one of these characteristics.

“The biggest aha, overall, is that some of the things that make CEOs attractive to the board have no bearing on their performance,” said Elena Lytkina Botelho, a partner at ghSmart and a co-founder of the project.