Know your numbers' is a fundamental precept of business.

To succeed, you also have to know how to make choices and how to think more broadly.

I realized about 10 years ago that my wealth has to go back to society. A fortune, the size of which is hard to imagine, is best not passed on to one's children. It's not constructive for them.

India just went 3 years with no cases [of polio]. Pakistan is our toughest location right now because some parts of the Taliban have not allowed vaccinators to come in and have even attacked vaccinators. We are hopeful this will get resolved since no one wants their kid to be paralyzed. I spend a lot of time making sure the polio campaign is doing the best it can. We have great computer models that help guide our activities.

I have been struck again and again by how important measurement is to improving the human condition.

Anyone who spends their life on a computer is pretty unusual.

Even with cameras being very cheap, one thing that researchers noticed was that you look really bad in a videoconference image because the lighting is bad and you get shadows and things.