And there is a lot of idiosyncrasy. But there are also regularities and phenomena. And what the data is going to be able to do - if there's enough of it - is uncover, in the mess and the noise of the world, some lines of music that actually have harmony. It's there, somewhere.

In technology, we spend so much time experimenting, fine-tuning, getting the absolute cheapest way to do something - so why aren't we doing that with social policy?

For millions of girls around the world, motherhood comes too early. Those who bear children as adolescents suffer higher maternal mortality and morbidity rates, and their children are more likely to die in infancy.

Part of me always wanted to do something useful for the world. It came from my mother. She is a paediatrician and she was active in a small NGO for the child victims of war.