Quick, what’s the average age of a successful startup founder? If you guessed something like 22 or 25—pretty much anything under 30—you’re probably influenced by the stories of Mark Zuckerberg, Steve Jobs, and other tech giants who founded their first companies at an extremely young age. But a new analysis by the Harvard Business Review suggests that founders of hugely successful startups are 45 years old, on average. (In this context, “successful” companies were in the top 0.1 percent based on growth during their first five years.) “The age finding is similar using firms with the fastest sales growth instead, and founder age is similarly high for those startups that successfully exit through an IPO or acquisition,” HBR explained in its article framing the data. “In other words, when you look at most successful firms, the average founder age goes up, not down.” With software-focused startups, the average age is 40, younger than at startups in other, more specialized industries such as biotech (where the average age is 47). “Among those who have started a firm, older entrepreneurs have a substantially higher success rate,” HBR added. “If you were faced with two entrepreneurs and knew nothing about them besides their age, you would do better, on average, betting on the older one.” Why is that? Simply put, older workers have more experience; by the time they reach their early 40s, they’ve probably seen and done quite a lot in their industry. While a kid fresh out of college might have a great idea or two, they’re unlikely to have the knowledge to properly shepherd their new company to sustainability (much less success). Indeed, when you look at hyper-successful companies such as Facebook or Google, you often find a young founder surrounded by older executives (such as Facebook’s Sheryl Sandberg or Google’s Eric Schmidt) who provide the necessary “adult supervision,” at least for the firm’s first few years. HBR’s conclusions, taken at face value, rub uncomfortably against the regular accusations of ageism leveled against the tech industry. In a recent Dice Survey, some 68 percent of Baby Boomers said they were discouraged from applying to jobs due to age; around 40 percent of tech pros from Generation X said the same thing. Overall, 80 percent of respondents voiced concerns that their age (and tech’s ageism attitudes) would affect their careers negatively. At least some of this ageism is driven by VC firms’ tendency to fund and promote startups founded by kids who can barely shave. More established companies also face complaints that they tend to hire younger employees in place of more mature ones. In both cases, however, the impulse to hire and fund youngsters might have relatively little to do with the kids’ smarts, and more with their willingness to work 80+ hours a week without needing to go home to a family. For tech pros, there’s a clear takeaway here: no matter what your age, you can still start a successful company. The myth of the young entrepreneur is just that—a myth, fueled in large part by a few ultra-successful outliers.