Backchecking with: Scott Cullen, Advanced Stat Guru

Posted: 06/11/2013 by bc in Uncategorized
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Call me old school. Really, it’s okay. I’m a big boy and have been wearing long pants for years now. As a kid I was always grateful to be two years ahead of the switch to new math. I never had the patience to sift through 3 pages of processing instructions that could best be explained succinctly in 3 sentences. In many ways the Advanced Stats movement impresses like new math. A convoluted and unnecessary process.
Jeez, watch and learn. Or better yet, play and coach. It’s how medical doctors learn. See it, do it, teach it.

The advanced stat movement employs some very roundabout methods for determining who has the puck and what they do with it when they possess it. This would be Corsi.
In this edition of Backchecking with, we examine tsn.ca advanced stat guru Scott Cullen Shots, Save Percentages into the Stanley Cup Final.
As always, my take is italicized.

In the first round, the team with the higher expected goals, using these calculations, won seven of the eight series, with the Los Angeles Kings’ win over the St. Louis Blues upsetting the bid for perfection.

Round Two brought middle of the road results, 2-2, with Jonathan Quickleading the L.A. Kings to exceed expectations and the Pittsburgh Penguins tearing through Ottawa’s top-ranked goaltending.

A betting man relying on this system to determine winners, would show a profit in the first round and a loss in the second round.

Since I’m the first one to emphasize that overall statistics (or standings) are not necessarily representative of the current value for a team, especially with respect to injuries, these statistics merely provide a baseline for the series, perhaps providing an idea what a team needs to do in order to emerge victorious.

That’s among the most wimpy disclaimers I’ve read ever. How ’bout “Don’t try this at home kids. It will rot your brain. Since we’re measuring offensive production by examining this advanced stat view will arrive at the conclusion that the team that scores the most goals usually wins.

In some cases, teams will simply need to keep doing what they’ve been doing throughout the regular season; in others, they might need better goaltending, or fewer shots against, or more shots for — just something — to provide better expected results in a seven-game series.

Just something? It’s the Cup! It’s the game of their lives.

The calculations below are simple and the expected goals for each team in the series are determined by taking each team’s shots for and against over the course of the season and splitting the difference.

Simple, eh. Well okay. If you insist. I’ d look at the GAA for each team and multiply by 7, rounding fractions up or down to the nearest whole number. I get 14 GF by each team but we know that can’t happen.

So, Chicago has 31.4 shots on goal per game through the regular season and three rounds of the playoffs and Boston has allowed 29.7 shots on goal per game; the average of those two numbers is 30.6 shots, so that’s the number that is then multiplied by (1 – the opposing goaltenders’ save percentage) to determine an expected goals per game.

Finally, the number is multiplied by seven to indicate an expected goal total for a seven-game series. There’s no guarantee that scoring more goals in a series will result in winning four games first, but the odds certainly favour the team that scores more.

The past has no bearing on the future.

Team                 SF       SA        Goaltender             SV%            ExpectedGF/ Series
Boston             33.4    29.7    Tuukka Rask          0.934                     14.93
Chicago           31.4    26.7    Corey Crawford    0.929                     14.11

Verdict: This is an even matchup, with a slight edge going to Boston because of Rask. It’s not that Crawford hasn’t played well for Chicago — he obviously has — but Rask’s .943 save percentage in the postseason trumps Crawford’s .935 and Rask also held an advantage in the regular season (.929 to .926) so there is some reason to believe that Rask may turn aside a few more shots.

If the difference is about five goals per 1000 shots and a seven-game series might yield approximately 200 shots, then the goaltending difference is only going to be worth about a goal. By no means is that decisive, rather it’s reason for a slightly more favourable forecast. (Worth noting that the Blackhawks are -140 to -150 favourites to win the series, depending on the site.)

Let me get this straight. Cullen says Boston scores more goals than Chicago and credits Tuukka Rask? Rask must make one heckuva first pass.
Still, one need look no further than SV% to know that Tuukka Rask is slightly better than Corey Crawford. You can even surmise from a peek at GF that Boston is slightly better offensively than Chicago.

What these stats don’t factor at all is the quality of competition Chicago faced in the Western Conference. Overall, the West is better defensively overall than the East. The difference between East and West skews the numbers sufficiently to show a theoretical edge to Boston.

If I’m betting and I’m not, Boston at plus $1.30 to win is the value play. Laying 40-50 cents on Chicago is just too much to pay. The teams are closer than the spread (betting public) indicates.

While we’re looking at percentages, it’s also worth considering that, in a short series, players may exceed (or fail to meet) their established performance levels. Blackhawks LW Bryan Bickell has been one of the exceptional ones, scoring on 22.9% of his shots in the playoffs, while Bruins RW Nathan Horton (22.9%) and C David Krejci (21.6%) are both over 20% as well. Eventually, regression catches up to that kind of shooting, but it could still hang on through one more series; such is the magic of small sample size.

On the other end of the spectrum, Blackhawks C Jonathan Toews has one goal on 51 shots (2.0%) and LW Brandon Saad has none on 35 shots, so they’re due for better results. Bruins RW Jaromir Jagr is still seeking his first goal, despite 45 shots in the playoffs, and RW Tyler Seguin has one goal on 54 shots (1.9%), so those numbers wouldn’t last over the long haul. If any of these players actually start scoring, that would figure to improve their respective teams’ odds of success.

Boston must stop, Toews, Kane and Hossa. Chicago must stop Krejci and Horton. The first order of business is to neutralize the best scoring threats. The success or lack thereof will determine the length of the series.

These are two of the top four possession teams, in both regular seasonand playoffs, so it’s not like either one relies on their goaltender or special teams to an unreasonable degree. While neither team has been great on the power play in the playoffs (15.6% for Boston, 13.7% for Chicago) the Blackhawks have had the league’s best penalty killing in the playoffs (94.8%), while Boston’s 86.5% has been strong, just not the best.

Again, quality of competition or degree of difficulty is increased in the playoffs such that statistics, like power play efficiency is expected to drop.

As referenced by Cullen and noted in this blog’s Cup preview, injuries are something the stats don’t measure. Greg Campbell impacts both Boston’s PK and forces Coach Julien to shorten his bench.

A short series favors Boston. A long series favors Chicago.

While Advanced Stats are interesting, they don’t tell you anything you don’t already know from the traditional stats and/or from watching the games. As suggested, Advanced Stats are indicative, the stats won’t tell you how to shift and stay with a Hossa, Kane or Toews.

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