A Hedgehog Concept is not a goal to be the best, a strategy to be the best, an intention to be the best, a plan to be the best. It is an understanding of what you can be the best at. The distinction is absolutely crucial.
The Hedgehog concept in a nutshell is to work at the intersection of three circles:
1) what you are deeply passionate about
2) what you can be the best in the world at
3) what best drives your economic or resource engine.
The Hedgehog Concept is developed in Jims book Good to Great.
Transformations from good to great come about by a series of good decisions made consistently with a Hedgehog Concept, supremely well executed, accumulating one upon another, over a long period of time.
I learnt about the Hedgehog Concept from an interview with Jim Collins (Tim Ferriss show).