Why is baseball easier to predict than presidential elections?
It's all about the amount of data that is available: while there are baseball games every day from spring to autumn, presidential elections only happen every four years.
As humans develop science and mathematics, our ability to predict events gets much better - for example, we keep improving our ability to predict the weather.
But even with more data there is a danger of becoming too confident in our capabilities.
Statistician and New York Times reporter Nate Silver's new book The Signal and the Noise seeks to unravel the mystery in the stats.