GPA is one of the most important markers of success in school — but in the real world, that number has less of an effect on life achievement or wealth.

Eric Barker, author of " Barking Up The Wrong Tree, " says that becoming a millionaire or billionaire doesn't require an outstanding GPA or being class valedictorian.

In fact, he says the average college GPA of American millionaires is 2.9.

In the video above, Barker explains what impacts success more than GPA.

What we see is that the average GPA, college GPA of American millionaires is actually 2.9.

So Karen Arnold did research at Boston College looking at the success levels of valedictorians. And, In general, high school valedictorians do well but they don't actually reach the highest level of success metrics. They don't become the billionaires. The people who run the world in general.

And that's because what the research found was that school teaches you to comply with rules. So valedictorians often go on to be the people who support the system, they become a part of the system, they don't change the system or overthrow the system.

And so what we see is that the average GPA, college GPA of American millionaires is actually 2.9. And while valedictorians generally score high in the personality trait of conscientiousness. What you see among the millionaires with their 2.9 GPAs is they're known for grit.

Maybe they don't comply with rules that well but they stick with goals over the long term. And that how they do really well. And sometimes they don't play by the rules, sometimes they do things differently. Because in school rules are very clear in life rules are not so clear.

So a certain amount of not playing by the rules is advantageous once you get out of a closed system like education.