Monday, November 14, 2011

The Florida Outlier

In honour of Ed Belfour's Hall of Fame induction, I thought to take a closer look at one of the weirdest single-season statistical anomalies that I can think of since the lockout.

The Florida Panthers have routinely been one of the worst teams in allowing shots against. Over the past seven seasons the team has had consistently good goaltending and consistently bad shot prevention. There was, however, one very large exception. See if you can pick it out:

2003-04: .924 save %, 34.0 SA/60
2005-06: .913 save %, 34.3 SA/60
2006-07: .899 save %, 28.9 SA/60
2007-08: .922 save %, 33.2 SA/60
2008-09: .925 save %, 34.3 SA/60
2009-10: .920 save %, 33.6 SA/60
2010-11: .918 save %, 31.5 SA/60

That raises the intriguing question: Did the lower shot totals in 2006-07 cause the goalies to have a correspondingly lower save percentage? Or was it the lower save percentage in the first place that caused the other team to take fewer shots against? Or were there some other factors at play?

The Panthers' starting goalie that year was Belfour, in the final season of his illustration career. Throughout his career, Eddie the Eagle typically faced fewer shots against than the other goalies that he has played with. Therefore, it seems quite likely that at least some portion of the effect is likely because of him. However, given the numbers through the rest of his career that suggest he prevents about one shot against per game compared to an average goalie, I don't think there is any chance at all that a 41-year old Belfour was able to prevent 4-5 shots per game entirely through his own efforts.

Here are the home/road splits for each goalie for 2006-07 along with the two seasons before and after:

Luongo, '04: 2.55, .926, 34.6 at home, 2.28, .935, 35.3 on road
Luongo, '06: 2.67, .920, 33.3 at home, 3.28, .909, 36.1 on road
Belfour, '07: 2.75, .901, 27.8 at home, 2.80, .903, 28.8 on road
Vokoun, '08: 2.55, .921, 32.2 at home, 2.85, .916, 33.9 on road
Vokoun, '09: 2.21, .933, 32.9 at home, 2.92, .915, 34.3 on road

From those splits it doesn't look like Florida changed their official scorer, as shots went down significantly in all venues.

Looking at the numbers for the backup goalies shows that there was a lot more to it than any individual discrepancies between Belfour and Luongo or Vokoun:

Steve Shields, 2003-04:
Starts: 3-6-1, 3.67, .874, 29.1 SA/60
Non-starts: 0-0-0, 2.37, .904, 24.6 SA/60

Jamie McLennan, 2005-06:
Starts: 2-3-2, 3.71, .895, 35.3 SA/60
Non-starts: 0-1-0, 1.43, .941, 24.4 SA/60

Alex Auld, 2006-07:
Starts: 7-13-5, 3.28, .889, 29.6 SA/60
Non-starts: 0-0-0, 4.55, .857, 31.9 SA/60

Craig Anderson, 2006-07:
Starts: 1-1-1, 2.54, .924, 33.3 SA/60
Non-starts: 0-0-0, 0.00, 1.000, 23.6 SA/60

Craig Anderson, 2007-08:
Starts: 7-5-1, 2.23, .936, 35.0 SA/60
Non-starts: 1-1-0, 2.33, .924, 30.8 SA/60

Craig Anderson, 2008-09:
Starts: 15-7-3, 2.75, .924, 36.0 SA/60
Non-starts: 0-0-2, 2.27, .931, 32.8 SA/60

The special teams numbers don't give much of a hint either, given that Florida had a below-average rate of power play opportunities and a higher-than-average rate of power plays against. Those two factors would typically result in more shots against, rather than fewer. The only major difference in the special teams numbers for '06-07 was the number of shots against per PK:

2003-04: 374 PPOA, 571 SA, 1.53 SA/PP
2005-06: 514 PPOA, 744 SA, 1.45 SA/PP
2006-07: 443 PPOA, 530 SA, 1.20 SA/PP
2007-08: 374 PPOA, 532 SA, 1.42 SA/PP
2008-09: 311 PPOA, 513 SA, 1.65 SA/PP

(PPOA=Power play opportunities against)

Jacques Martin was the coach from 2005-06 to 2007-08, which makes it even more surprising that the numbers would change so suddenly.

Team shots for:

2003-04: 2273
2005-06: 2724
2006-07: 2730
2007-08: 2549
2008-09: 2412

Given that '05-06 was skewed by a high rate of power plays, this suggests that the Panthers were a much better territorial team in '06-07.

Florida had similar personnel in '06-07 compared to '05-06. Jay Bouwmeester was the #1 defenceman and Olli Jokinen was the #1 forward. Nathan Horton (21) and Stephen Weiss (23) both probably took large steps forward in 2006-07, and may have had some impact on turning results around, although the two of them remained in Panther uniforms until 2009-10 while Florida's results dropped back to their usual levels. The defence replaced Sean Hill, Lukas Krajicek and Joel Kwiatkowski with Ruslan Salei, Bryan Allen and Steve Montador, which is probably an upgrade. Still, it remains curious that there was such a huge difference in results. If a personnel change was responsible for the sudden shot drop, why did it reappear again the following season?

Breaking down shots against by period from the Hockey Summary Project, the biggest drop in shots against from '05-06 to '06-07 came in the first period:

First Period: -196 (-20%)
Second Period: -104 (-11%)
Third Period: -113 (-13%)
Overtime: 0 (0%)

I looked at the leading and trailing numbers, and 2006-07 does not appear to be an outlier in that regard. The Panthers may have played a more low-event game early on, suppressing shots against in the first period. However, there was clearly a significant shot prevention effect throughout the entire 60 minutes.

The last thing I thought to look at was blocked shots:

2003-04: 463 home, 549 away, 1012 total
2005-06: 403 home, 454 away, 857 total
2006-07: 501 home, 520 away, 1021 total
2007-08: 410 home, 570 away, 980 total
2008-09: 485 home, 620 away, 1105 total
2009-10: 584 home, 819 away, 1403 total
2010-11: 507 home, 618 away, 1125 total

This may explain some of the effect, perhaps reflecting a strategic shift by the Panthers' defence to adjust for the team's weaker goaltending. There is still a large amount left unexplained, however, as combined blocked shots and recorded shots against still show a drop of about 300 during 2006-07 compared to the seasons before and after.

For what it's worth, given that shot quality measures have tended to be unreliable and not predictive year-to-year (see Gabe Desjardins' summary rant on the subject), Alan Ryder estimated the Panthers' shot quality at 0.957 in 2005-06, 1.014 in 2006-07, and 1.008 in 2007-08 in his annual NHL reviews. Numbers below one indicate easier than average shots against while numbers above one indicate more difficult than average shots. That would support the hypothesis that the Panthers were able to block or prevent more long-range shots in '06-07 compared to '05-06. However, the shot quality estimate was similar in '07-08 compared to '06-07, despite the large increase in shots against.

I still don't entirely know what to make of the Florida's team defensive performance in 2006-07, it looks like a confluence of factors was responsible for the one-year dip in the team's shots allowed. It makes sense that the Panthers would have played more conservatively that year because of the goaltending change, leading to more blocked shots. The metrics suggest that team improved in terms of puck possession and spent more time at the other end of the rink, which helped cut down shots against. Switching goaltenders from Roberto Luongo to Ed Belfour may also have had a shots against impact of 1-2 shots per game. Other contributing factors could have been improved penalty killing as well as facing fewer opposing power plays against as players adjusted to the new post-lockout rules.

Yet while that may account for the changes from '05-06 to '06-07, it still doesn't explain why the Panthers dropped back to their usual awful shot prevention level during '07-08 and following years. It looks like coach Martin and his skaters put everything together for one season, but then for whatever reason were unable to recreate that success. Unfortunately for them, the one season where they managed to put together a pretty strong team effort (.898 win threshold, 13th best in the league) was also the one season where the team's goaltending was poor, and the result was yet another non-playoff appearance for the Florida Panthers.


Robert Vollman said...

Great tenacity on this case!

Jokinen as their top forward and Bouwmeester as their top defenseman - no wonder they missed the play-offs!

Um ...

Alexander said...

Interesting post, I am so glad that I have visited your site. Really useful information!

Bruce said...

You and I had some back and forth on that sequence of Panthers seasons in the past. Agree that it is very odd, and that it's a confluence of factors of which Belfour's puckhandling is likely a fraction.

I will maintain he was better than his save percentage that season.

Anonymous said...

TCG, can you please make a post about Tim Tebow. I know this is a hockey blog, but I am so sick of hearing the phrase "he just wins".

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