Wednesday, December 21, 2011

Are there "good team" goalies and "bad team" goalies?

In "The Game," Ken Dryden argues that some players are not psychologically suited to playing on good teams:

Because the demands of a goalie are mostly mental, it means that for a goalie the biggest enemy is himself. The fear of failing, the fear of being embarrassed ... The successful goalie understands these neuroses, accepts them, and puts them under control. The unsuccessful goalie is distracted by them, his mind in knots, his body quickly following.

It is why [Rogie] Vachon was superb in Los Angeles and as a high-priced free-agent messiah, poor in Detroit. It is why Dan Bouchard ... lurches annoyingly in and out of mediocrity. It is why there are good "good team" goalies and good "bad team" goalies -- Gary Smith, Doug Favell, Denis Herron. The latter are spectacular, capable of making near-impossible saves that few others can make. They are essential for bad teams, winning them games they shouldn't win, but they are goalies who need a second chance, who need the cushion of an occasional bad goal, knowing that they can seem to earn it back later with several inspired saves. On a good team, a goalie has few near-impossible saves to make, but the rest he must make, and playing in close and critical games as he does, he gets no second chance.

A good "bad team" goalie, numbed by the volume of goals he cannot prevent, can focus on brilliant saves and brilliant games, the only things that make a difference to a poor team. A good "good team" goalie cannot. Allowing few enough goals that he feels every one, he is driven instead by something else -- the penetrating hatred of letting in a goal.

Dryden seems to be saying at least three things here:

1. Some goalies, like Rogie Vachon, can't handle pressure.
2. Some goalies are better on bad teams than on good teams.
3. Those two groups are the same goalies.

I'm very skeptical about #1, especially with regards to Rogie Vachon. Yes, Vachon had a serious decline after leaving the Kings -- with Detroit, he was worse by more than a goal a game (3.90 to 2.86). But, was it really Vachon's neuroses? After all, he was 33 years old that year. Dryden may know Vachon pretty well -- they were together on the Canadiens for a few months in 1971 -- but is that enough for him to conclude that Vachon's problem is that he choked under pressure?

I'll skip over #3, also, and concentrate on #2, the part about "good team" goalies and "bad team" goalies. What Dryden seems to be saying, as an empirical hypothesis, is something like this:

There are some goalies who make brilliant saves that few others can, but also give up more weak goals. Those goalies are more valuable to bad teams, because bad teams give up more scoring chances where brilliant saves are required. It wouldn't make sense for a good team to pick up a goalie like that, because they'd get only the weak goals, but not the brilliant saves.

That's actually a pretty interesting theory! And it seems plausible. After all, what a team should care about is how many goals a guy allows, not how he looks doing it. A goalie with a 2.50 GAA is more valuable than a goalie with a 2.75 GAA, even if the first guy lets in more bad goals than the second guy.

But, is there any evidence for it?

Not in the book. Dryden gives us only those three examples of "bad team" goalies. Unfortunately, they played on bad teams for most of their careers.

Still, we have a few datapoints.

-- Gary Smith left Oakland (bad) to play two seasons for the Black Hawks (good) as Tony Esposito's backup. The first year, he was very good; the second year, he was mediocre.

-- Denis Herron moved from (bad) Pittsburgh to (good) Montreal (where he replaced Ken Dryden). Like Smith, he was great the first year, but not so great the second year.

-- Doug Favell was nothing special in his last season with Toronto (an average team). Then, he went to a below-average Colorado Rockies team, where it seems like he was pretty good. So, maybe that's a plus.

But, overall ... no real evidence either way, really. And Dryden doesn't give any examples of "good team" goalies, so there's nothing to check there.

But ... maybe here's something we can do.

Goalies play some of their games against good teams, and some against bad teams. If Dryden is correct, that Smith, Herron and Favell give up more bad goals but also make more spectacular saves, they should do better than expected against good teams, and worse than expected against bad teams. That's because they'll give up roughly the same amount of bad goals each way, but they'll make more brilliant saves against the good teams.

Does that make sense? Maybe we can find a way to check that.

Here's how that might work. In 1977-78, the Penguins, with Denis Herron as their regular goalie, gave up 321 goals, or 4.01 per game. That season, the best five teams (alphabetically) were the Bruins, Canadiens, Flyers, Islanders, and Sabres. The worst were the Barons, Blues, Canucks, Capitals, and North Stars.

From the game log, I manually calculated that against the five best teams, the Penguins gave up 5.25 goals per game. Against the five worst teams, they gave up 3.14.

For that to be evidence that the Penguins have "bad team" goalies, you'd have to show that 5.25 goals against good teams is actually better than expected for a team that gives up 4.01, and that 3.14 against bad teams is actually worse than expected for a team that gives up 4.01.

How would you do that? Well, one thing you could do is find a matching team, one that also gave up 4.01 goals per game (or close to it), but had a random goalie. If that team gave up 6.00 goals against the good teams, but 2.50 against the bad teams, that would be confirmatory evidence.

The match wouldn't be perfect, because it might have to be from another season, and the "best" and "worst" groups might not be comparable. Still, even with just those three goalies, you'd have about 33 seasons to compare (if you require a minimum 30 game season). If you found the two most comparable instead of one, that would be 66 comparisons.

That's better than nothing. But there'd still be a lot of noise. To make it workable, you'd have to limit your sample to games those goalies started (in 1977-78, Herron himself gave up only 3.57 goals per game, compared to 3.96 for the team after subtracting empty net goals). There'd be even less noise if you used save percentage instead of goals against.

The process would be a bit like searching for clutch hitting, only with a lot less data. And it would be a lot of work ... but, there's an organization, the Hockey Summary Project, that collects NHL game summaries -- like a hockey Retrosheet -- and I've asked them for access to their database. I'm hoping they have shots on goal. (Also, those summaries might help us trying to trace the games that Dryden talked about in his book, the ones that didn't match the game logs.)

Before I go any further, does this make sense as a way to test Dryden's hypothesis? Can you think of any others that might be easier?

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At Friday, December 23, 2011 12:36:00 PM, Blogger The Contrarian Goaltender said...

Goalie statistical analysis is my hobby, and I'd say there is enough evidence from today's NHL to reject the theory of good team and bad team goalies. Some of the best evidence there would include goalies posting relatively consistent save percentages when changing teams, relatively consistent shot quality from team to team, penalty kill save percentages that generally correlate with even strength save percentages over the long run, and the fact that backup goalies on good teams almost always also have very good win/loss records. I also don't like the fact that this theory always seems to be a post hoc argument rather than a predictive one.

So even if Dryden was right, I don't think it matters anymore. That said, it's at least possible that things were different in the 1970s, where greater competitive imbalance and less standardized goalie technique at least make it somewhat plausible that certain goalies may have performed significantly better on some teams than others (although I'm still skeptical).

If you want to run the numbers on this, I wouldn't advise using GAA. Even if you find a significant result, you won't be sure if it was because of the goalie or because of his teammates. You'd probably be better off defining teams as good or bad based on their overall records, and then using the unofficial save percentage numbers from Hockey Summary Project to evaluate goalie performance against each level of opposition.

At Friday, December 23, 2011 12:47:00 PM, Blogger Phil Birnbaum said...

Thanks ... and, hey, a new blog to check out!

I'm still waiting to be approved for the Hockey Summary Project files ... meanwhile, I did some quick calculations and any effect would be too small to pick up, I think, even with save percentage. I should post that ...


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