Is Alex Edler the best defenseman in Canada?

What makes a good defenseman? Not allowing goals against? Ice-time? Plus/minus? I think it has a little more to do with how good shooters are when they're out against you.

I'm at my parents' place, so my copy of Moneyball isn't handy, but I recall baseball historian and statistician Bill James being quoted in it as saying that he didn't want statistics to manipulate his thought. James wanted to watch a game, compile data from the game and see what gave the winning team its success.

To determine the qualities that make a good goal scorer great, you have to take the reverse to determine what makes a defenseman good. The data that I've compiled based on 15 games isn't enough to draw up totally what makes a hockey team good, but I've noticed a couple of trends: