From the New York Times:

Founders of Successful Tech Companies Are Mostly Middle-Aged

By Seema Jayachandrank, Aug. 29, 2019

… Mr. Fadell’s deep experience and relatively mature age when he started Nest are typical of superstar entrepreneurs, who are rarely fresh out of college — or freshly dropped out of college. That’s what a team of economists discovered when they analyzed high-growth companies in the United States. Their study is being published in the journal American Economic Review: Insights.

The researchers looked at start-ups established between 2007 and 2014 and analyzed the top 0.1 percent — defined as those with the fastest growth in employment and sales. The average age of those companies’ founders was 45. …

The research, by the economists Pierre Azoulay of M.I.T., Ben Jones of Northwestern, J. Daniel Kim of the University of Pennsylvania and Javier Miranda of the United States Census Bureau, provides the first systematic calculation of the ages of the founders of high-growth start-ups in the United States.

… The new study was able to zero in on high-flying start-ups by bringing together anonymized data collected by different agencies within the federal government. The government matched sales and employment data for start-ups collected by the Census Bureau with information on the founders extracted from Internal Revenue Service filings.

After stripping identifying information, the government provided the researchers with a data set including 2.7 million business founders.