Here is an interview with Jim Simons, founder of Renaissance Technologies, one of the most successful quantitative investment management funds ever.
there's something called the efficient market theory which says that there's nothing in the data, let's say price data, which will indicate anything about the future, because the price is sort of always right, the price is always right in some sense. But that's just not true. So there are anomalies in the data. ... And you put together a collection of these subtle anomalies and you begin to get something that will predict pretty well.
If you've got an hour over the weekend, check it out (h/t and thanks)
