Hockey analytics: Defencemen give Canada oh-so-slight advantage in Olympic semifinal

When two men’s hockey teams are as closely matched as Canada and the U.S., the difference between skating for gold and playing in the loser’s bracket can come down to which one shuts down the other’s biggest weapons.

So the Department of Hockey Analytics set out to identify and analyze the Canada-U.S. semifinal’s critical matchups. We wanted to see whether one team had the kryptonite to the other’s Superman. The Delilah to the other’s Samson. The Road Runner to the other’s Wile E. Coyote.

There were just two problems. First, Team USA’s big gun has been Phil Kessel. Kessel plays in the Eastern Conference, and all of Canada’s main D-men play in the West, so there’s effectively no track record to speak of. Second, due to Canada’s forwards’ futility, Canada’s best offensive player has turned out to be a defenceman, and it didn’t seem to make much sense to try to figure out whether Ryan Suter has a history of shutting down Drew Doughty.

With Canada’s offensive juggernaut acting more like a ladybug, and without any indication of which of Canada’s forwards will be the first to find his game, we decided to look at the next best thing to power matchups: A straight-up analysis of which team had the better shutdown defencemen.

Defensive play is one of the most difficult aspects of the game to measure accurately. Commentators focus on plus/minus, but plus/minus is a deeply flawed statistic because it ignores how each player is used. Most importantly, it says nothing about whether a player is consistently matched up against his opponents’ best players — as most of the best defensive players are — which will naturally lead to a lower plus/minus.

As a result, you end up with Hampus Lindholm at +26 this year (third in the NHL), Zdeno Chara at +10 (71st), and Shea Weber at -10 (729th). Clearly plus/minus doesn’t tell us who the best defensive players are.

Instead we looked at a purely defensive statistic: Fenwick Against.

Fenwick Against measures the number of unblocked shots attempted by the opposition when a particular player is on the ice. Fenwick is one of the “go-to” stats in the advanced stats community because it is actually one of the strongest predictors of wins — the idea being that teams attempting more shots are probably carrying the play, which leads to more goals, which leads to more wins.

We calculated the average Fenwick Against per 60 minutes of playing time over the past three NHL seasons for the four defencemen logging the most ice time for each team.

Canada: 37.8

U. S. 37.8


Undaunted, we dug deeper. Like plus/minus, Fenwick doesn’t account for player usage. To remedy that we used a fantastic tool from to generate a player usage chart that illustrates which of the eight defencemen were logging the toughest NHL minutes. The Player Usage Chart’s vertical axis shows the quality of the competition each defenceman plays against (how this is calculated will have to wait for another day), and the horizontal axis reflects whether the defenceman starts more shifts in the offensive zone or defensive zone.

The players in the top left therefore play the toughest minutes; they play against the best competition and tend to start shifts in their own defensive zone.

The chart shows that in general, the Canadians play tougher minutes, though not overwhelmingly so. Canada’s Shea Weber gets by far the hardest assignments. Kevin Shattenkirk of the U.S. by far the easiest, with the other six mixed around in between.

What does this all mean? Well, even though both teams’ top defencemen averaged 37.8 Fenwick Against per 60, the Canadians’ 37.8 is “better” than the Americans’ because Canada’s top defencemen have played tougher minutes.

Canada wins! Sort of.

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If the game is as close as these stats indicate, it’s going to be a doozy.

1 Comment

  1. March 24, 2014    

    Wow that was strange. I just wrote an extremely long comment but after I clicked submit my comment didn't show up.

    Grrrr... well I'm not writing all that over again.
    Anyhow, just wanted to say excellent blog!

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