Revisiting the expected goals model

The past is a pretty good predictor of the future, which is why a lot of models of future performance are based upon past performance. Earlier this season, we used past shooting (and saving) performances to predict how many goals the Calgary Flames should be expected to score (or allow).

As you’d expect, a lot of the team’s issues can be heaped upon a handful of players when performance is analyzed through this lens.

Let’s dive in!

THE METHOD

We took a look at this back in January. To quote, us, back then:

Admittedly, the Expected Goals model I am using here is simplistic. I
like it because it’s simplistic, but that does limit its effectiveness
sometimes. Here’s the gist: based on a player’s career shooting (or
save) percentage, you can project how many goals they should score (or
allow) based on the number of shots they have (or have faced). This
approach pinpoints individuals that are scoring more or less than they
should be, and goalies that are allowing many more (or fewer) goals than
they should be.

All shots are equal under this formula, which is
one drawback. And for younger players – Sam Bennett, for example – it’s
less effective because for them the current season could be their entire
career. It’s a tool, but it’s not bulletproof by any means.

SKATERS

Through 73 games; for difference, a positive number is good. Significant numbers are bolded.

Player Actual
Goals
Expected
Goals
Difference 15-16
S%
Career
S%
Gaudreau 27 27.7 -0.7 14.1 14.5
Monahan 26 27.9 -0.9
14.4 15.5
Giordano 19 14.5 +4.5
9.9 7.6
Colborne 16 12.4 +3.6 18.4 14.2
Backlund 15 11.6 +3.4
10.9 8.4
Frolik 15 11.7 +3.3
10.4 7.9
Bennett 15 14.9 +0.1 12.8 12.7
Hudler 10 12.0 -2.0
12.5 15.0
Hamilton (D) 10 9.5 +0.5 6.1 5.8
Jones 9 9.1 -0.1 13.4 13.6
Stajan 6 7.3 -1.3
10.9 13.3
Brodie 4 4.0 0.0 5.8 5.8
Russell 4 2.8 +1.2
7.1 5.0
Ferland 4 4.6 -0.6 3.6 4.1
Jooris 4 7.4 -3.4
5.3 9.8
Granlund 4 4.6 -0.6 10.8 12.5
Raymond 4 5.1 -1.1
7.5 9.6
Wideman 2 4.6 -2.6
2.7 6.1
Bouma 2 3.9 -1.9
4.7 9.1
Engelland 1 2.9 -1.9
1.6 4.7
Bollig 1 1.6 -0.6 2.1 3.3
Nakladal 1 1.0 0.0 3.7 3.7
Hamilton (F) 1 0.3 +0.7 25.0 7.1
Jokipakka 0 0.3 -0.3 0.0 2.5
Hathaway 0 0.0 0.0 0.0 0.0
Kulak 0 0.0 0.0 0.0 0.0
Smid 0 0.4 -0.4 0.0 3.3
Grant 0 0.0 0.0 0.0 0.0
Wotherspoon 0 0.0 0.0 0.0 0.0
Agostino 0 0.2 -0.2 0.0 6.7
TEAM
200 202.2
-2.2
9.4
9.5

GOALIES

Through 73 games; for difference, a negative number is good. Significant numbers are bolded.

Goalie Actual
GA
Expected
GA
Difference 15-16
Sv%
Career
Sv%
Ramo 94 97.2 -3.2
.909 .906
Hiller 76 55.2 +20.8 .883 .915
Ortio 40 40.5 -0.5 .901 .900
Backstrom 1 1.9 -0.9 .955 .915
TEAM 211 194.7 +16.3 .900 .908

THE NUMBERS

Significant Positive Differences (A Goal Or More):

  • 4.5 – Mark Giordano
  • 3.6 – Joe Colborne
  • 3.4 – Mikael Backlund
  • 3.3 – Michael Frolik
  • 3.2 – Karri Ramo
  • 1.2 – Kris Russell

Significant Negative Differences (A Goal Or More):

  • 20.8 – Jonas Hiller
  • 3.4 – Josh Jooris
  • 2.6 – Dennis Wideman
  • 2.0 – Jiri Hudler
  • 1.9 – Sean Monahan
  • 1.9 – Lance Bouma
  • 1.9 – Deryk Engelland
  • 1.3 – Matt Stajan
  • 1.1 – Mason Raymond

Where do we begin? Okay, let’s get this out of the way: it’s probably unfair to single out Jonas Hiller for sinking the Flames season, but if he was anywhere close to what he used to be – or close to what he was last season – he probably gives up at least 10 fewer goals than he did and the Flames are in the playoff hunt. They might not be in, but they’re in the mix.

On the sunny side: Giordano has really gotten hot lately, which has driven his expected goals into the black quite nicely. Colborne’s shooting percentage shouldn’t be the best on the team and is due for a big correction, but given where he usually shoots from (right in front of the net) he should have a percentage around 12 or 13. Backlund and Frolik have benefited from playing with each other, and Ramo was quietly quite good for a while before he got hurt.

On the down side: Already mentioned Hiller (yeesh), and any questions about Calgary’s lack of scoring depth should be directed to the handful of players that haven’t scored at their expected rates. Prime among them are Monahan and the departed Hudler, who were ice-cold for the first couple months of the season.

    • freethe flames

      Suggesting Monahan is the cause of the scoring problem is silly. Let’s look at the real problems: Stajan, Jooris Bouma, and Wideman. Any of these guys score 2/3 of last year numbers and things are significantly different; this is of course if the the goaltending(Hiller)was better.

      What this really suggests is the NEED to add more top end talent. We have not found a RW to play with Johnny and Monny and we have to some extent experimented with every RW on the team. Is there anyone on the farm to fill that position? Based on the play of the RW the answer is not yet. Could someone else in the system be the answer long term. maybe.

      It also says that we need more talent to fill out a second scoring line. Is there potential from within the team or from the farm? Again the answer is maybe but probably not yet. Grant, Shinkaruk, Agostino, and Poirier all might be able to help there as might Mangiapane. But it seems that the help needs to come via a trade, the FA market or the draft. BT will need to address this in the off season but will need to find a way out of the salary cap handcuffs he is in. Good luck.

      • Bananaberg

        Every team needs to add top-end talent. That’s the main objective, always. Same goes for second line and goaltending.

        I’ve been impressed with how Backlund and Frolik have been playing together.

        You’re correct to suggest BT et al face an interesting cap situation. There are certainly some contracts worth launching, if and where possible, but it won’t be easy.

        Tanking the final 9 games of the season to maximize our chances at Matthews (or bridesmaid, Patrik Laine) would be a good start….force Bennett to play the wing.

    • KACaribou

      How many times do I have to point out that every shot is not equal?

      The number of grade A shots the Flames team-D was giving up early in the season were far higher than later in the year.

      Don’t forget to blame the terrible D coverage. Don’t forget to blame all Dougie Hamilton’s cough-ups which led to grade A chances. Don’t forget to blame new D-combinations.

      Continually blaming the goalies, is like blaming QBs when the receivers drop the ball thrown right to their hands. It’s why completion percentage is a flawed stat like save percentage.

      It doesn’t tell the whole story fairly, just partially.

      Hiller had a bad year, but he is not to blame alone. That’s simplifying things.

      • wot96

        I agree with this. If the D have confidence in the goalie, they don’t grip their sticks so tight, they don’t worry about playing mistake free hockey, they don’t run around trying to do everything because they are afraid of the result if someone drops the ball. Confidence in the goalie leads to higher confidence amongst the D generally and, I think, better defensive structure. Lack of confidence gets the D running around and leads to blown coverages and good opportunities.

        Neither the Flames nor Hiller recovered from that early run in the season when Brodie was hurt and Hamilton was still adjusting to the club, its style and the style in the Western Conference. Fairly or unfairly that landed on Hiller and is evident in the results. Thing is, there wasn’t much, or at least didn’t appear to be much, push back from Hiller even when Brodie was back and Hamilton was playing better and that is ultimately what sunk him.

        If you are secretly embracing the tank, you should probably thank Hiller. If you are disappointed with the season, well, Hiller is a big part of the equation.

        • KACaribou

          Sensible… I agree fully.

          I wasn’t ever disputing Hiller’s average-at-best play, but I can’t stand when people can’t think outside the box and just blame the whole thing on Hiller. Bull$#it.

          BTW: Hamilton’s play early was terrible, but I can now see the young man have a chance at a Norris someday. He is a spectacular offensive D-man.

    • Truculence

      “Already mentioned Hiller (yeesh), and any questions about Calgary’s lack of scoring depth should be directed to the handful of players that haven’t scored at their expected rates. Prime among them are Monahan and the departed Hudler, who were ice-cold for the first couple months of the season.”

      So, you’re telling me 1.9 more goals (difference between actual and expected) by Monahan would have turned the season around?

      Now I’m gonna be harder on the kid.

    • Thunder1

      This is how stupid your statistical model is. If Monahan goes hatty on Saturday night he goes from your worst ranking to one of the best. You have no validity. Utter garbage!