Editor’s note: Vivek Wadhwa is Wertheim Fellow at the Harvard Law School and executive in residence at Duke University. He is a tech entrepreneur who founded two technology companies, including Relativity Technologies in Cary. This article is reprinted with permission of BusinessWeek.

DURHAM, N.C. — American tech entrepreneurs are young college dropouts—often from prestigious universities—who start companies out of their garages. So goes the stereotype, reinforced by tales from the dot-com boom and examples such as Bill Gates and Steve Jobs. But recent research I helped lead at Duke and Harvard shows that most U.S.-born tech entrepreneurs are middle-aged and well-educated.

Most don’t graduate from top-tier universities (BusinessWeek.com, 8/31/07) – they come from an assortment of schools. Twice as many tech entrepreneurs start ventures in their 50s as do those in their early 20s, according to our research.

So just who is the typical, U.S.-born, tech entrepreneur?

While getting at related questions about immigrant entrepreneurs, we surveyed 652 U.S.-born chief executive officers and heads of product development in 502 engineering and technology companies established from 1995 through 2005.

Here is what we learned:

A surprise about age

Contrary to the popular belief that tech entrepreneurs start their companies in their teens or early 20s, we found that the average and median age of founders was 39. Twice as many were older than 50 as were younger than 25.

And there were twice as many over 60 as under 20. So, we may read stories about young people starting tech companies, but they’re the minority. Most tech entrepreneurs have gray hair and experience.

Very few tech entrepreneurs dropped out of college to start their companies. We found the vast majority (92 percent) of founders held bachelor’s degrees, 31percent held master’s degrees, and 10 percent had completed doctorates.

Nearly half of these degrees were in science-, technology-, engineering-, and mathematics-related disciplines. And one-third were in business, accounting and finance.

Almost every major U.S. university was represented in the ranks of company founders—including schools such as The University of Southern Mississippi and Akron University. Only 8 percent graduated from Ivy League schools.

But that was significantly higher than their proportion of all graduates. In other words, you don’t need to graduate from an elite university to become an entrepreneur, but graduates of Ivy League schools were more likely to become entrepreneurs than others

For the remainder of Vivek’s column, see