That is,this kind of pull-yourself-up-by-your-bootstraps, that with enough determination and hard work that you can transcend limitations of money or class or gender.

VOA: special.2010.03.08

"I think in terms of swimming once you've lost that motivation and determination you're never going to get to a point that's as good as your potential, " Achieng adds.

BBC: Decision time for British swimmer Achieng Ajulu-Bushell

It's inevitable that you will go through tough times, and that your idea will evolve a lot, but what differentiates you as a startup founder is the determination you have to stick with it, and your ability to adapt.

BBC: Viewpoint

Our ranking will help you make that determination by comparing the cost of attaining an M.

FORBES: The Rankings