With founders like Mark Zuckerberg, Jack Dorsey and Bill Gates, it may seem like billion-dollar start-ups are all started by 20-something college dropouts.
The book's author, Ali Tamaseb, a partner at the tech venture capital firm DCVC, says he spent thousands of hours combing through internet archives, interviews and reviewing thousands of LinkedIn and Crunchbase profiles collecting data — 65 different data points, to be exact, like age, education and experience — on every unicorn start-up started between 2005 and 2018.
"It took about four years," Tamaseb tells CNBC Make It.
Tamaseb says he collected over 30,000 data points and included both private and public companies with billion-dollar valuations and companies whose acquisitions brought them to that value.
"It's not just tech [companies]. It includes biotech, energy, fintech and everything else," he says.
Tamaseb found that "[a]cross billion-dollar companies, the age range is quite substantial. Some founders were as young as eighteen, others as old as sixty-eight when they started their companies," he writes. "The median age of a billion-dollar startup's founder was thirty-four years old—meaning half the founders of billion-dollar startups were that age or older when they got started."
Tamaseb's data showed a slight advantage for younger founders in creating larger valued companies, but nothing statistically substantial, Tamaseb says.
That means when it comes to building a billion-dollar start-up, "age doesn't matter," he says.
Tamaseb also found that two-thirds of unicorn founders who were 34 or older had previously started another company before their billion-dollar business. So it didn't happen overnight.
"All of them have a history. All of them have a past. On average, they have over a decade of work experience," he says.
More broadly, 2018 research published in the Harvard Business Review found that the average age at which a successful founder started their company is 45. That's "among the top 0.1% of startups based on growth in their first five years," according to the report.
The HBR report also found that entrepreneurs with at least three years of prior work experience in the same industry as their start-up were 85% more likely to succeed.