"The most overrated thing since natural childbirth is starting your own business."

-- A piece of graffiti cited by Kathleen Brown, former California secretary of the treasury, to make a point about how starting a business is much more difficult than most people believe

Not much when it comes to running your own business. That's one conclusion you could draw from a study by Harvard Business School (HBS) professor Amar BhidÉ that compares 87 HBS entrepreneurs with 100 CEOs from the Inc. 500 list of 1989 (10% of whom hold M.B.A.'s).

Bhid found, not unexpectedly, that most of the HBS graduates went first to large corporations and then migrated to entrepreneurship over time. The odd part was that their business-school experience appeared to have little effect on their entrepreneurial behavior. According to BhidÉ, their business strategies were "only somewhat more systematic and deliberate" than those of the Inc. 500 CEOs. Both groups, for example, typically got the idea for their businesses from previous employment or as the result of plain serendipity. One-third of the HBS entrepreneurs had detailed business plans -- and so did 28% of the Inc. founders.

On the other hand, an HBS degree does seem to provide access to money. The Inc. founders were bootstrappers, setting out -- on average -- with $10,000 in capital. By contrast, the median amount of start-up capital for the HBS group was $200,000.