Bracketology 101: NCAA Tournament Metrics for Beginners

Does it seem like every year there are more numbers and more stats involved in projecting the NCAA tournament field? First it was KenPom, then the NET, then Quads, now this thing called WAB. What are all these metrics and terms, and how does the committee use them? 

First, we should define useful terms in the context of NCAA tournament selection.

Metric - “A system or standard of measurement.