The Streakiness of Stamkos

I thought this was kind of interesting:

Steven Stamkos, 2010-11:

First 22 games: 21 goals, 4.0 shots per game
Next 6 games: 0 goals, 2.8 shots per game
Next 10 games: 10 goals, 3.7 shots per game
Next 6 games: 0 goals, 3.7 shots per game
Next 7 games: 7 goals, 2.6 shots per game

That makes two goal-less streaks the length of a typical playoff series for Stamkos this season, even in the midst of a truly dominant stretch of goalscoring.

I can imagine the kind of silly things the media would be tempted to write if Stamkos just happened to hit another 0 for 6 streak some time in late April. To the right kind of reactionary, frequentist, narrative-loving mind, that would reflect his flawed inner character, prove he was a perimeter player unsuited to the playoffs, show that he hasn't yet learned what it takes to win, and probably confirm a dozen other meaningless cliches that you've heard many times before. All because the release point on that famous one-timer may have been off by a couple of centimetres for a few games in a row.

This type of thing is why it is so important to compare performances to a baseline. Do you think your hometown scorer is playing poorly because he hasn't scored in two weeks? Maybe he is, but that is not necessarily the case, he might just be on a streak of bad luck. In any event it's far from abnormal, it happens to the elite as well. Just look at Stamkos.

How The Game of Hockey Taught Me That Goalie Wins Don't Matter

There was a personal story posted over at Lighthouse Hockey by "Mikb" (who is also an occasional commenter here) that I wanted to use as a starting point in a discussion on the impact of hockey experience on goalie evaluation. Here's an excerpt of what he wrote, reproduced with his permission:

I was on a very successful team for a number of years – I was the MVP of a tournament we won, won a few leagues with the guys, good times – and then a lot of the guys I’d started with began to leave… jobs, age, moving away, etc. etc. The guys who were left were pretty good too, but we wound up losing four seasons in a row (we play three seasons per year, usually)…. tough OT losses, one loss in a nine-round shootout. These are single-eliminations, too, at least until the best-of-three final. ANYTHING can happen in a single game like that.

Well – those new guys kicked me off their team. Another team gladly snapped me up, and for the first year (three more seasons) it was the same thing… in fact, I think we got shut out each of the games.

If I had to guess, I’d say I had about a 1.50 GAA with nothing to show for it except a big fat scapegoating. Then just this Tuesday night, my new team and I finally won. It was easily my WORST game out of the whole lot – two horrible goals against in the first five minutes, and my guys pulled [me] out of it with a big final period.

So – it annoys me when I hear stuff like “not clutch,” “learning how to win,” and “playoff choker.” I didn’t forget how to win for three years, and just remember this week. I wasn’t choking. I wasn’t “big when they needed it.” Hell, if I HAD been even barely competent early on, I wouldn’t have needed to make ANY big saves, we would have been winning 3-0, there would have been no OT heroics and no shootout saves.

I think a lot of that is probably very familiar to long-time goalies, the vast majority of whom would have their own anecdotes about either taking heat for losing on a bad team or having to do little more than show up to win behind a powerhouse.

When I was much younger, I remember disagreeing with an older goalie who stated that a goalie is mostly just as good as the team in front of him, but as much as anything else it was my experience that changed my outlook. I don't think it was ever more clear to me that I was just one small part of an overall team effort than in one particular game where in my estimation I played about as well as I could possibly play and my team still lost 4-0. On a different day maybe I would have been a bit luckier, maybe they wouldn't have made a few of the shots that they made and we could have at least still squeaked a tie out of it, that's the variability of goaltending and that's always the hope that goalies cling to for the next outing. But on that day I was in peak form and it didn't matter one bit, we still got crushed.

The other thing that I concluded from both personal experience and subjective observation is that it is ridiculous to describe people in absolutes, and that you are doomed to failure if you expect to be able to perfectly predict performances based on past results. Like Mikb points out, labels are easily applied but mostly meaningless; I see them as the product of bias and lazy thinking. Some individuals may have tendencies, even more so at lower levels of play, but people are complicated and randomness happens. Every athlete knows that they are not consistent every time out, regardless of their best intentions.

There was one particular big game I played in where I was just completely out of form. I had been playing well leading up to it, and I wasn't that nervous and didn't feel any different than usual before the game, right up until the point where I realized that I could barely catch a puck in warmups. That's when I started to get a bit concerned (perhaps another example in support of Kent Wilson's argument that confidence is an effect, not a cause?) I spilled rebounds on most of the shots against that day, but luckily my defence was outstanding and we ended up with a shutout win.

Other times in that exact same scenario I've been calm and confident. I don't think I'm a choker or a clutch player, but it's entirely possible that next time out I might choke and the game after that my play will be supremely clutch. I'm not a robot with only one setting, and I don't believe anyone else is either. I've been described before as trying to "erase the human element" by discounting clutch play, but I hardly see how it is any more of an acknowledgement of the human element to have a perspective of players as video game characters who perform exactly the same way in every clutch situation based on the value of their "poise" rating. Good days, bad days and luck are all big parts of that human element, and are likely all big reasons why it is difficult to find evidence of clutch skill in the data.

I want to make it clear that I am not saying that we can extrapolate every beer league observation and apply it to the pros. Their level of talent and preparation is on a completely different level and they are playing for much, much higher stakes. At the end of the day, though, they're still people, and they are still playing the same sport with the same basic rules as the peewees down at the local rink.

That's why I struggle to understand how anyone could play a large number of games as a hockey goaltender on a variety of different teams without coming to the conclusion that rating goalies based on wins and team success is a foolish endeavour. I think it must simply be the case that conventional hockey wisdom is at fault, and that the cliches and coaching points that people hear at the rink, on TV and around the game have taken root to such a degree that people let them overshadow their own observations.

Sometimes the problem areas of sports logic stick out most clearly when they are compared to an analogous setting in a different area (which, as someone who is a bit of a stickler for logical consistency, I like to do every now and then). It's a rare individual indeed who wouldn't scream and yell and cry martyr when he gets blamed individually for the failings of others at work or school, but for some reason that same guy goes home and sits down in front of his TV and heaps scorn on the quarterback or the goalie when his team loses. It doesn't make a lot of sense, especially if that guy had sports experiences of his own the prior weekend that should have further reinforced the point. It really does seem that hockey groupthink has a powerful impact on many observers.

So, if you are one of those types who think that stats are meaningless and Cup rings are the litmus test for a goalie and that Chris Osgood is a fully deserving Hall of Famer but Grant Fuhr was the best you ever saw, I can only recommend that you strap on the pads and get into a game and focus on your own observations. If you are honest with yourself and if you take the time to compare your experiences against some of the premises that you have long accepted as uncontested fact, I think you just might come around to a different way of thinking on the matter.

Road Performance - Active Goalies

There are a number of active or recently retired goalies who did not meet the minimum games cutoff for my last post. I wanted to run the road numbers on them as well to see if there were any interesting results. I decided to limit it to goalies with at least 250 games played, to avoid guys with really small road samples. Unlike the last post, these numbers include 2010-11 numbers.

Active or recently retired goalies:

1. Tim Thomas: +.013 save %, +58 goals

2. Ryan Miller: +.009 save %, +45 goals

3. Henrik Lundqvist: +.009 save %, +42 goals

4. Niklas Backstrom: +.009 save %, +29 goals

5. Manny Fernandez: +.006 save %, +29 goals

6. Kari Lehtonen: +.007 save %, +27 goals

7. Manny Legace: +.005 save %, +22 goals

8. Cam Ward: +.004 save %, +15 goals

8. Ilya Bryzgalov: +.004 save %, +15 goals

10. Cristobal Huet: +.001 save %, +3 goals

11. Chris Mason: +.000 save %, +0 goals

12. Kevin Weekes: -.001 save %, -3 goals

13. Rick DiPietro: -.003 save %, -13 goals

14. Vesa Toskala: -.005 save %, -19 goals

15. Marc-Andre Fleury: -.005 save %, -22 goals

16. Johan Hedberg: -.005 save %, -23 goals

17. Mathieu Garon: -.006 save %, -24 goals

18. Andrew Raycroft: -.007 save %, -26 goals

19. Brian Boucher: -.007 save %, -31 goals

20. Patrick Lalime: -.007 save %, -39 goals

21. Marc Denis: -.014 save %, -71 goals

- There is a clear top three here, which isn't too surprising, although I didn't expect Miller to rank ahead of Lundqvist. Given that the Swede is two years younger than the American it is still probable that King Henrik ends up ahead over the long run.

- As I discussed in the comments to my last post, Buffalo actually was much more disciplined at home than on the road during this period, yet Miller's save percentage was .912 at home and .916 on the road. I think there may have been a difference in style of play for the Sabres at home through much of Miller's career, with a lot more scoring taking place in Buffalo home games. Perhaps that affected Miller's numbers, as going by road stats only he looks like an elite goalie. I think it is possible he was a bit underrated based on his numbers when the Sabres had their terrific offensive team going immediately after the lockout.

- This is also a reminder that Roberto Luongo stands head and shoulders above his goaltending peer group in terms of career success. Despite being just one year older than Miller and three years older than Lundqvist, Luongo has double the road goals against average of either of his rivals.

- Adjusting for special teams factors would put Kari Lehtonen solidly in fourth on this list, considering that the Thrashers faced more power plays than average while Backstrom and Fernandez both had the benefit of playing on very disciplined Minnesota squads.

- Cam Ward is coming on strong in this ranking. His numbers were hurt by being rushed to the NHL before he was ready in 2005-06 and 2006-07, but he is +20 over the past two and a half seasons.

- Cristobal Huet was very good at home (.919) and very average on the road (.908). I think that, knowing what we know now, Huet was probably never as good as his numbers suggested he was during his peak from 2006 to 2008. In addition to the road numbers, which suggest a potential helping hand from either teammates or the official scorer, Huet also has the other warning sign for goalies: Strong numbers on special teams compared to average numbers at even strength. Huet's career EV SV% of .918 is right at league average over the course of his career, while his career PK SV% of .887 and his career PP SV% of .961 are both off the charts relative to the league average from 2002-03 to 2009-10 (.866 and .913 respectively).

- Yes, Pittsburgh fans, you read that right: Marc-Andre Fleury rates below Vesa Toskala. Toskala had a couple of nice years in San Jose that pull his numbers up, but Fleury has never really been all that good on the road in his career.

- I remain baffled as to why some of the goalies near the bottom of this list were able to carve out such long careers. It makes no sense that a guy like Patrick Lalime is still drawing an NHL paycheque. He has never that good of a goalie, and he has only gotten worse in recent seasons. Lalime's post-lockout save percentage is .894 and the Sabres are 9-25-5 with Lalime in net over the last three seasons. Any random starting goalie from the AHL or the Swedish Elite League would probably beat those numbers. There are too many good goalies out there today for any team to keep giving washed-up veterans opportunities at the highest level.

- Marc Denis: Yikes. Denis was 29.7 goals below average on the road in 2002-03, second only to Jeff Hackett's brutal record behind the completely outclassed San Jose Sharks in 1992-93. To be fair, Denis was on a young expansion team as well, and the third-year Blue Jackets ranked fourth in the league in power play opportunities against. That said, Denis only had one season in his career with positive goals above average on the road. It looks to me like his career may have been aided by some fortunate timing, as the Quebec goalie factory was at the peak of its reputation when Denis broke into the league in the mid-'90s. If his name was Mark Dennis, would he have lasted as long as he did in the NHL? His numbers certainly make one wonder.

Goalie Performance on the Road

It has been shown pretty convincingly that the definition of a shot on goal can vary from rink to rink around the NHL. The problem is that there is still a fair bit of guesswork involved in trying to tease out exactly which rinks may be padding the stats and which ones may be shorting them, and even once we can prove that there has been a track record of bias in one city or another it could still change instantly with a single hiring decision.

In response to this uncertainty, I thought to take an ultra-conservative route in this post and assume that every official scorer in the NHL is so biased that they can't be trusted for anything at all related to the home team. Under that assumption we would have to throw out all home save percentage data and rely on road numbers only, hoping that any potential undercounting or overcounting will roughly balance out for goalies who play in a variety of rinks on the road.

In addition to the issue of scorer bias, it seems more likely that a team could control their style of play while in their home rink. To quote Vic Ferrari, "When a team wants to play a low tempo game, the opponent is more likely to oblige in your barn than in front of their own fans." The home team has last change and can decide whether it wants to shut down the opposition's best players with a defensive line or whether to slug it out power vs. power. It seems that the level of parity in today's NHL is such that there is little difference in shot quality from team to team, but if there are any persistent team effects on a goalie's numbers from style of play it seems more likely that they would appear in the home sample than in the road sample.

I'd like to break these down by game situation, ideally, but that special teams goaltending data only goes back about a decade or so whereas detailed home/road splits for all goaltending stats are available going back to 1988 on Hockey Reference. For each season, all home games were thrown out and the road numbers were adjusted based on the league average that year. Current season results were not included.

Nothing changes much in terms of rankings at the top of the list, but there are a few goalies with unusual results that either indicate that there may have been something going on with the shot counting or with the team's style of play at home. On the other hand, perhaps they really enjoyed that home cooking, or maybe it is no more than a statistical quirk arising from cutting the sample size in half. Nothing can be proven with any certainty by this type of surface analysis, but there are some team situations that definitely seem to warrant a closer look.

The goalies are sorted by road goals saved over average, calculated by subtracting the league average save percentage from the goalie's road save percentage for each season and then multiplying by the number of shots faced on the road. Note that since goalies typically have better numbers at home than on the road, comparing to league average means that this definition of average is a slightly higher standard than usual. Current goalies with fewer than 450 career games played were not included for now, but will be discussed in a future post. Keep in mind also that these numbers represent partial career results for goalies who played in the NHL prior to 1987-88.

Tier 1: The Elite

1. Patrick Roy: +.015 save %, +180 goals

2. Dominik Hasek: +.017 save %, +163 goals

3. Martin Brodeur: +.010 save %, +145 goals

4. Ed Belfour: +.009 save %, +110 goals

5. Roberto Luongo: +.010 save %, +92 goals

Tier 2: The Good

6. Marty Turco: +.006 save %, +40 goals

7. Curtis Joseph: +.003 save %, +36 goals

8. J.S. Giguere: +.005 save %, +35 goals

9. Felix Potvin: +.003 save %, +27 goals

10. Dwayne Roloson: +.003 save %, +25 goals

11. John Vanbiesbrouck: +.003 save %, +25 goals

Tier 3: The Average

12. Evgeni Nabokov: +.002 save %, +14 goals

13. Chris Osgood: +.001 save %, +12 goals

14. Tomas Vokoun: +.001 save %, +11 goals

15. Sean Burke: +.001 save %, +10 goals

16. Nik Khabibulin: +.001 save %, +5 goals

17. Guy Hebert: +.001 save %, +4 goals

18. Jose Theodore: +.001 save %, +4 goals

19. Ron Hextall: .000 save %, +3 goals

20. Mike Richter: .000 save %, +2 goals

21. Martin Biron: .000 save %, -1 goal

22. Andy Moog: .000 save %, -2 goals

23. Tom Barrasso: .000 save %, -2 goals

24. Miikka Kiprusoff: -.001 save %, -8 goals

25. Jocelyn Thibault: -.001 save %, -10 goals

26. Jeff Hackett: -.002 save %, -12 goals

27. Arturs Irbe: -.002 save %, -16 goals

Tier 4: The Mediocre

28. Ron Tugnutt: -.003 save %, -19 goals

29. Kelly Hrudey: -.003 save %, -26 goals

30. Olaf Kolzig: -.003 save %, -32 goals

31. Tommy Salo: -.005 save %, -33 goals

Tier 5: The Dinosaurs

32. Ken Wregget: -.006 save %, -39 goals

33. Grant Fuhr: -.006 save %, -46 goals

34. Mike Vernon: -.006 save %, -57 goals

35. Kirk McLean: -.007 save %, -58 goals

36. Bill Ranford: -.007 save %, -65 goals

Some points of discussion:

- The top five really separate themselves from the field by this metric. All are 50+ goals better than the rest. Both Brodeur and Belfour had higher save percentages on the road than at home over the course of their careers, and both benefit quite a bit from going on away numbers only. In fact, assuming the road numbers accurately reflect the overall level of performance and taking into account shot prevention while also recognizing both Roy's team advantages in Montreal as well as the weaker pool of goaltending talent that Patrick was competing against in the late '80s, plus the fact that Roy retired younger than the other two and skipped his decline phase, there may not actually be that much separation between the three of them in terms of regular season results.

For example, if we add one shot prevented to Belfour's save percentage and assume that Brodeur's shot prevention is balanced out by his special teams advantages, then both are around 145 goals saved. All it would take to drop Roy to roughly the same career number is to assume that either he created one extra shot per game against on average or that his expected save percentage was understated by .003 because of weaker competition or Montreal's defensive play and team discipline. Having said that, this doesn't take into account playoff play and the 1988 cutoff means Roy isn't getting credit for two of his seasons. Brodeur is also on pace to give back around 15 goals compared to average this season if he can't fix his struggles in the second half.

- In his first 12 seasons in the NHL, Curtis Joseph saved his teams 68 goals compared to league average on the road. In his final 7 seasons, he gave 32 of them back. Joseph's early career peak would have put him near the elite group, but he did not have anything close to the staying power of the top 4.

- Sean Burke is the anti-Cujo, with -41 in his first dozen seasons and +50 in his final six. If you want further evidence of my argument that it was technique not equipment that was driving the changes in goaltending through the '90s, you'd be hard-pressed to find better examples than Burke and Joseph. Joseph's athleticism allowed him to excel early on, but when that faded as he aged the game rapidly passed him by. In contrast, Burke remodeled himself into a butterfly blocker and put up his best performances in the twilight of his career.

- If you define a goalie's peak as his best five consecutive seasons with a significant number of games played (and including numbers from light workload seasons that fell within the same stretch), Burke ranks an impressive 7th in peak road goals above average per game, trailing only Hasek, Roy, Joseph, Belfour, Luongo and Brodeur.

- Other surprise goalies in the top 15 for peak road results include Jeff Hackett (9th), Dwayne Roloson (10th), Felix Potvin (11th) and Arturs Irbe (15th).

- Arturs Irbe had an eight season stretch where he was 37 goals better than average on the road, playing three of them behind the fledgling San Jose Sharks. His overall numbers nosedived when he stuck around too long after his game fell off a cliff in Carolina, but that was a pretty impressive run without much team support at all.

- To show the kind of impact playing on the Sharks in the early '90s had, Jeff Hackett was -44 goals in San Jose in the first two seasons of that expansion franchise and +32 everywhere else.

- Trivia question: From 1992-93 to 1997-98, which goalie ranked third behind Hasek and Roy in most goals above average on the road? Not Brodeur, not Belfour, not Joseph, not Vanbiesbrouck. Would you believe Felix Potvin? Potvin was a lot like Cujo in that he didn't age well, but there was a lot to like early in his career, even though a lot of people underrate him because he played for mostly mediocre teams.

- Chris Osgood ranks 13th in career total, but just 25th in peak. Osgood has a close comparable in Evgeni Nabokov, who ranked 12th and 29th respectively. Nabokov had a few more peaks and valleys than the fairly steady Osgood, but the end result is that neither was able to put together a five season stretch on the road that was any better than slightly above average for a starting-calibre goalie.

- The biggest surprise on this list has to be Miikka Kiprusoff coming out as slightly below average. Throughout his career, Kiprusoff has a .920 save percentage at home compared to just .906 on the road. Even in his 2006 Vezina year Kiprusoff did not have great results on the road (a mere .904 in 35 games played). The confusing thing is that his shots against split is 27.0 per 60 at home compared to 29.6 per 60 on the road, which really doesn't seem to suggest a generous home scorer.

If there is a logical explanation for this, I'm not aware of it. Was Calgary more disciplined at home, did they change their style of play, did they benefit from lots of back-to-back games against teams that had just played the Oilers? I really have no idea.

- Olaf Kolzig is another guy who had underwhelming results relative to his reputation on the road both overall and in a Vezina winning season (.903 in 1999-00).

- Tomas Vokoun is another interesting case. His save numbers have been very good, especially post-lockout, but he has a Kiprusoffian home/road split of .923/.910. Vokoun's road numbers in Nashville were actually below average, which makes it seem even more clear that there is something going on in Nashville. Vokoun's numbers are better in Florida, although some remain skeptical about his performance there as well.

- I strongly suspect that Guy Hebert got his stats padded in Anaheim. He is a guy that I've noted before as often doing well in various save percentage rankings, but that's probably a bit misleading as Hebert was very average on the road and has another extreme home/road split (.916/.902).

- I still have no idea where to rank Tom Barrasso. Like the rest of his stats, his road numbers are all over the place throughout his career, although he'd presumably rate above average if his extra seasons from the mid-eighties were included.