Lou Gerstner resurrected IBM with no previous knowledge of IBM’s business. He proved that a lack of company, even category, experience can be overcome. Gerstner was the exception.

A CEO with the full body of knowledge about a company and its category has a huge leg up. CEOs who grow up in a company know the pressure points at every level. They know where each job fits in the total scheme. They know the industry. And that means they know the competition.