This talk is titled "Who's number one? from ranking to bracketology".
The speaker talked first about how often we use ranking algorithms every day (e.g. Google). He discussed how predictive methods aren't trying to predict upsets (usually). They're trying to predict the most likely outcomes.
We talked about how we can graph a sport season and rank teams by wins. Winning percentage isn't as good as when we take into account strength of schedule. Strength of schedule, mathematically, is taken care of with linear algebra. Each game creates a dependency between the two teams, expressed as an equation.