Clayton Christensen and the steel mill cost research

How Tom's airport-napkin estimate of integrated steel mill cost ended up referenced in *The Innovator's Dilemma*. Pairs with the bracketed reflection on factual provenance in §5.p7.

Anybody think of a famous management book? What's the most famous one to come out of Harvard Business School over the last 25 years? The Innovator's Dilemma. Clayton Christensen. If you mentioned that 15 years ago in Washington, everybody thought you were God if you knew about disruptive technology. Have you heard the term "disruptive technology"? That's Clayton's term. I've known Clayton since he was a graduate student. In fact, my daughter worked on part of the book, and you'll find me referenced in the book, because my daughter came home one day — she was working one summer doing some research for Clayton — and she said, "Dad, what's it cost to build a steel mill? I've looked all over and I have not been able to find any number that tells you how much it costs to build a steel mill." Clayton has three examples, and one of them is the steel industry. I think one was the computer industry, and the other might be healthcare. But he talked about disruptive technologies.