How could Digital's collapse be so precipitous? It's because, in many ways, financial performance data is misleading. As you move up to the top of the market, you're getting rid of the less profitable products at the low end and adding business with more attractive margins at the high end. The rate of unit volume growth might be tapering off as you pursue these smaller markets, but your margins actually look better. So Wall Street rewards your stock price until you hit the ceiling.

Disruptive technology is a theory. It says this will happen and this is why; it's a statement of cause and effect. In our teaching we have so exalted the virtues of data-driven decision making that in many ways we condemn managers only to be able to take action after the data is clear and the game is over. In many ways a good theory is more accurate than data. It allows you to see into the future more clearly.

...it's easier to hold to your principles 100% of the time than it is to hold to them 98% of the time.

I was lucky enough to build on the work of a number of people who had already run laps around this theory-building track. The original classification scheme, years ago, distinguished radical from incremental change. The theory said that established firms managed incremental change well, but would be expected to founder when their industry encountered a radical change.

Christine and I haven't raised our children. A whole community of selfless Christians has contributed to helping them become faithful, competent adults.

When product performance outstrips the ability of customers to use that performance in an industry, the competitive game changes. Under those circumstances you have to decouple components businesses from assembly businesses.

There's usually some process by which a potentially great idea gets prostituted into something lacklustre, or by which the wrong idea gets put forward.