You can invest to create the new growth business while the core business is still growing, because new business units don't need to get big fast. But when the core business stops growing, investing to create new growth businesses becomes impossible.

In general, the questions that are on our mind are the same questions that have been driving our work over the past decade. How do we bring order to this messy, unpredictable world of innovation? How can we dramatically improve the chances of creating a successful new-growth business? How can we do this again and again? More specifically, it has become very clear that the fundamental paradigms of market segmentation and branding are badly broken - and we're working on developing more useful theories for these dimensions of innovation.

I've concluded that getting the categories right is an absolutely crucial step to building useful management theory, and unfortunately too few writers do this. You've got to engage in serious scholarship, and then figure out how to write it in a way that lots of people can understand.

If you want to make better theory, you've got to use the best that's available and look through the lens of another discipline to see if you can uncover more anomalies. By looking at the phenomena of failure from the perspective of sales, marketing, finance, general management, and the equity markets, I was able to see things that Rebecca [Henderson] hadn't.

Watching how customers actually use a product provides much more reliable information than can be gleaned from a verbal interview or a focus group.

Whenever we have thanked these men and women for what they have done for us, without exception they have expressed gratitude for having the chance to help - because they grew as they served.

In the first stage of insight-building, all that researchers can do is observe phenomena. Second, they classify the phenomena in a way that helps them simplify the apparent complexities of the world so they can ignore the meaningless differences and draw connections between the things that really seem to matter. Third, based on the classification system, they propose a theory. The theory is a statement of what causes what and why, and under what circumstances.