Advanced Stats: Corsi, QoC, etc

[The Bored Man]

Corsi may tell us something at the team level but it's near useless when considering individuals. Problem is that you need to be a fanatic in order to use it for individual players. The results often aren't pretty. These are some posts from a Scott Gomez thread made by a person who shall go unnamed.

All these people bashing Gomez yet he still is a +1 while 5 on 5 and registers a 0.569 Fenwick. His PDO is 990. He may not be shooting that well but his linemates are shooting very well while he is on the ice.

Lets compare that to Brad Richards who many will say is having a slightly disappointing year. He is a -2 while 5 on 5 with a 0.476 Fenwick. During that time his PDO is 999. This while on the top team in the East.

Who would I take to finish this season regardless of salary?....Scott Gomez in a freaking second.

I will continue to post some stats that are more useful then goal totals.

SFON/60 - 29.6
SAON/60 - 22.4

Where did I say he was earning his salary? I am saying he is an excellent possession player. I would rather have the puck in the offensive zone more then the defensive zone. I can see the Fanboys are uniting! If you think a "playmaker" doesn't increase his linemates goal rate then you serious are lost.

In my experience at least, this kind of attitude is the norm rather than the exception when discussing something with the advanced stats crowd. Primarily through Outscoring Champion of the World Shawn Horcoff.

The best way to learn about a player is to watch him play. Stats can be useful, but they completely skew reality when used as a primary method of analysis. No pun intended.

 

[GKJ]

Advanced Stats aren't meant to be used as absolute gospel, and people who write about/using advanced numbers will tell you that.

Here is a 1hr10min hockey analytics conference at MIT that includes some team reps including Stan Bowman.

http://video.mit.edu/watch/hockey-analytics-7187/

Corsi's weakness is that it treats all shots, missed shots and blocked shots equally and defines QoC by the same metric. Teams appear to keep their own stats which are better than the public stats used in the blogosphere's articles.

For instance if you kept possession time by zone as the NHL did in the 90s, then you could go through the same analysis by defining QoC in terms of other player's relative possession time by zone etc, etc and deriving conclusions based on that. So the method may be sound, but the underlying stat (Corsi) is not close to perfect.

That's why it evolves to Fenwick.

Raw Corsi is also good to understand for beginners, but Corsi Rel and Corsi Rel QoC are better indicators because they used other factors.

The reason this stuff gets used as a proxy is because no one can possibly watch all 1230 NHL games let alone watch all 1230 NHL games AND properly evaluate players.

The Preds have completely lived off a hot power play and a hot goaltender. If the Preds are favorites in the first round against Detroit, Chicago or St. Louis, bet against them and win big.

This is the problem Nashville runs into, because they've been proven to be successful at it for years, but it wouldn't translate into the playoffs since it's not the regular season.

http://blogs.thescore.com/nhl/2012/...edicting-nashvilles-regression-five-theories/

Any system that treats every shot the same will be mostly blind to why these teams are succeeding. Not all shots are created equal.

http://www.arcticicehockey.com/2011/11/28/2591407/fun-with-pdo

Unless you honestly think Kent Huskins that good, Shot Quality is roughly 11% of the game. Advanced Stats covers the other 89%.

 

[Les Wynan*]

Yeah, the Predators have been a good possession team (i.e. above 50%) for years but for some reason are just horrible at it this year. I don't agree with some of the matchups Trotz has gone with - like using Fisher power against power when he has a vastly superior two-way center in Legwand to play the tough minutes. They also miss Ward a lot.

They're ironically a lot like the Ducks team they faced last postseason - terrible possession team riding a flukey power play and the percentages to the playoffs only to (likely) get drilled in the first round.

 

[njdevil26]

Devil fans use them a lot... but I ignore them...

I've played enough hockey, watched enough games at EVERY level... Peewee, midget, bantam, juniors, echl, ahl, swedish elite league, khl, nhl, international, and so on that I don't have to look at stupid corsi numbers to find out if a player is a good player, playing well, and so on.

 

[The Macho King]

Yeah, the Predators have been a good possession team (i.e. above 50%) for years but for some reason are just horrible at it this year. I don't agree with some of the matchups Trotz has gone with - like using Fisher power against power when he has a vastly superior two-way center in Legwand to play the tough minutes. They also miss Ward a lot.

They're ironically a lot like the Ducks team they faced last postseason - terrible possession team riding a flukey power play and the percentages to the playoffs only to (likely) get drilled in the first round.

That was also the Lightning last season, but they were a goal away from the SCF...

Look, advanced stats are awesome for understanding some of the nuts and bolts of the game, but I don't know how much they can really be applied. Hockey is a flukey sport. You can make some assumptions (say a player is scoring with a far higher shooting % than normal like Giroux at the beginning of the season), but the game is too fluid to put it on a spreadsheet like baseball.

 

[Les Wynan*]

That was also the Lightning last season, but they were a goal away from the SCF...

Look, advanced stats are awesome for understanding some of the nuts and bolts of the game, but I don't know how much they can really be applied. Hockey is a flukey sport. You can make some assumptions (say a player is scoring with a far higher shooting % than normal like Giroux at the beginning of the season), but the game is too fluid to put it on a spreadsheet like baseball.

Wait, what? The Lightning were the third best possession team in the NHL last season.

The fact that hockey is a flukey sport is exactly why possession metrics have value at the team level. They illustrate how much of a team's success is due to unsustainable factors.

 

[Les Wynan*]

Devil fans use them a lot... but I ignore them...

I've played enough hockey, watched enough games at EVERY level... Peewee, midget, bantam, juniors, echl, ahl, swedish elite league, khl, nhl, international, and so on that I don't have to look at stupid corsi numbers to find out if a player is a good player, playing well, and so on.

You must be much smarter than the Canucks, Sharks, Bruins and Penguins organizations then, all of whom are heavily invested in advanced metrics to make personnel decisions. But I mean it's not like any of those teams have ever won anything.

 

[Bjorn Le]

Unlike advanced stats in baseball, there are too many factors that these stats don't take into account which make them all but useless.

 

[The Macho King]

Was referring more to riding a hot power play to victory, as we were pretty ****** in 5 on 5 last season.

 

[Les Wynan*]

Was referring more to riding a hot power play to victory, as we were pretty ****** in 5 on 5 last season.

By goal differential, yeah, but they were pretty unlucky. They controlled the play at an elite rate but PDO took a giant crap all over their heads.

 

[Lafleurs Guy]

Hockey is a fluid game and it doesn't lend itself nearly as easily to stats as baseball does. Mircrostats are interesting and sometimes illuminating but I don't give them much weight. On our forum we've had people defending Gomez for two years because his CORSI is good. It's like CORSI has become the standard by which a player is successful or not. Way too much weight is given to them by some people and actual production takes a back seat.

If you've ever watched Gomez, he takes the puck brings it into the opposing zone very well but then... nothing. He's pretty ineffective and his point totals are a reflection of his uselessness. However, his CORSI is strong and so some folks assume he's playing great hockey. CORSI and other microstats are interesting but they shouldn't replace actual totals when analyzing a player's offensive performance.

People who point to Moneyball and baseball are missing the boat. With every at bat in baseball there is an empirical result. It is a statistically driven game that lends itself to that kind of statistical analysis.

Hockey is a much more fluid game and it's difficult to nail down with stats. Look at hits for example. All hits are measured the same. But does a hit from Brian Gionta feel the same as one from Chara? No. But there's no way to measure this. There's no way to measure the impact of what that hit has except via maybe... wins or +/- but even then there are tons of variables like goaltending, opponent ect...

As another example I"m not sure how CORSI is supposed to meaningfully show us how effective a player really is. It certainly doesn't always match up with production from players. Gomez is exhibit A. As I mentioned above, he was terrible despite those CORSI numbers.

I would expect that Brett Hull would be exhibit B. That guy didn't hold onto the puck too much. He didn't carry it into the zone and he didn't dipsy doodle around defenseman. But he was one of the best offensive threats of his generation. Puck would be on his stick and then in the net. I would guess that his CORSI wouldn't be all that strong but... so what? The guy was a beast. Again, CORSI might tell you that he wasn't a puck possession guy but I don't think that really means all that much in the grand scheme of things. It's certainly not an accurate predictor of how effective a player he was.

Moreover, there's the problem of the accuracy of the microstats themselves. Look at giveaways/takeaways... it's an official NHL stat and there's huge variances all over the league. If the NHL can't get it right on something that seems so simple then I'm not sure how we can really trust a bunch of bloggers with microstats that aren't officially kept by the league itself.

 

[number72]

Using corsi (shots directed to and away from the net) gives more "data" then looking at goals (directed to and away from the net or +-). Basically with more data, the belief is this gives a better picture if a player is effective, because goals are somewhat luck driven (and have smaller sample size).

 

[Juxtaposer]

As long as you used context, then they can help paint a good portrait of a player's situation, but obviously they can only really be a supplement to watching the player.

 

[The Bored Man]

Advanced Stats aren't meant to be used as absolute gospel, and people who write about/using advanced numbers will tell you that.



That's why it evolves to Fenwick.

Raw Corsi is also good to understand for beginners, but Corsi Rel and Corsi Rel QoC are better indicators because they used other factors.

The reason this stuff gets used as a proxy is because no one can possibly watch all 1230 NHL games let alone watch all 1230 NHL games AND properly evaluate players.





This is the problem Nashville runs into, because they've been proven to be successful at it for years, but it wouldn't translate into the playoffs since it's not the regular season.

http://blogs.thescore.com/nhl/2012/...edicting-nashvilles-regression-five-theories/



http://www.arcticicehockey.com/2011/11/28/2591407/fun-with-pdo

Unless you honestly think Kent Huskins that good, Shot Quality is roughly 11% of the game. Advanced Stats covers the other 89%.

This exemplifies another issue that I've encountered in discussing these stats. Their proponents often adopt this superior intelligence pose. If you don't accept them, then you're too dumb to understand them. Words like "advanced," "true," and "real," get tossed around a lot.

 

[AfroThunder396]

Like all stats, they are absolutely useless without context.

They have their place though. If Player A and Player B are tied in points, TOI, play on similar teams, and are equal in all other traditional metrics, but Player A has significantly better Corsi, then yeah that adds something substantial to the argument. But taking a rookie on the President's Trophy teams and screaming BUT HE HAS BETTER CORSI THAT JAGR is pointless and actually detracts from your argument.

My issue is with real time stats: shots, hits, blocks, giveaways, and takeaways are not standardized at all and prone to arena bias. Teams like Florida grossly over report shots which inflates their goaltender's save percentage, while teams like the Rangers are notorious for over reporting hits.

 

[Keaver]

So wait people are saying that advanced stats are a legitimate way to compare players with similar stat lines? Yet when people mention that giroux's advanced stats blow Stamkos out of the water people just can't accept that maybe giroux is the better player. Man hfboards you slay me.

 

[GKJ]

This exemplifies another issue that I've encountered in discussing these stats. Their proponents often adopt this superior intelligence pose. If you don't accept them, then you're too dumb to understand them. Words like "advanced," "true," and "real," get tossed around a lot.

That's simply the eye of the beholder. It shouldn't put you off if you find their proponents to have arrogance.

 

[Les Wynan*]

This exemplifies another issue that I've encountered in discussing these stats. Their proponents often adopt this superior intelligence pose. If you don't accept them, then you're too dumb to understand them. Words like "advanced," "true," and "real," get tossed around a lot.

And you're arrogant enough to believe that by watching the game you can make more accurate assessments of player value and more reliable predictions about player performance than through statistical analysis. It cuts both ways.

I'm not a fan of appealing to authority but when you see how much success Vancouver, Boston, San Jose and Pittsburgh have had using similar (albeit more "advanced" - hey it's one of your favorite words!) metrics that emphasize team possession and a player's contributions to team possession it's hard to argue that "watching the gamez!!!!1" is the be-all end-all or anywhere close. Not to mention that for most people, perhaps not you, "watch the gamez!!!1" as an anti-stats argument means "read the box score and see who had the most points."

 

[BillDineen]

And you're arrogant enough to believe that by watching the game you can make more accurate assessments of player value and more reliable predictions about player performance than through statistical analysis. It cuts both ways.

I'm not a fan of appealing to authority but when you see how much success Vancouver, Boston, San Jose and Pittsburgh have had using similar (albeit more "advanced" - hey it's one of your favorite words!) metrics that emphasize team possession and a player's contributions to team possession it's hard to argue that "watching the gamez!!!!1" is the be-all end-all or anywhere close. Not to mention that for most people, perhaps not you, "watch the gamez!!!1" as an anti-stats argument means "read the box score and see who had the most points."

I think there is a subtlety that is being missed. The stats analysis is not wrong. If teams keep scoring chances and/or actual possession do their own analysis by the exact same method as corsi/fenwick and define relative and quality of competition by their own stats (possession or scoring chances in the example), no one here has said that is wrong and it would likely give teams some more insight than public stats. It is just harder than baseball because of the continuous play in hockey. Treating all shots or shots and missed shots the same has errors in its use, but I am sure there are more effective ways teams use stats than what bloggers/posters do.

 

[Les Wynan*]

I think there is a subtlety that is being missed. The stats analysis is not wrong. If teams keep scoring chances and/or actual possession do their own analysis by the exact same method as corsi/fenwick and define relative and quality of competition by their own stats (possession or scoring chances in the example), no one here has said that is wrong and it would likely give teams some more insight than public stats. It is just harder than baseball because of the continuous play in hockey. Treating all shots or shots and missed shots the same has errors in its use, but I am sure there are more effective ways teams use stats than what bloggers/posters do.

The issue is no one has been able to find an instance of a team where scoring chances for/against are not proportional to Fenwick for/against. It's not that "all shots are created equal" - that's obviously a ridiculous and completely untrue statement - it's that the notion some teams are able to control shot quality to a greater degree than others has largely been proven to be false. PDO invariably regresses to the mean long term.

Just because some people might misuse advanced stats is no reason to discount them - seems like that was the rationale behind BoredMan's dismissal of the numbers.

 

[HyPnOtiK]

So wait people are saying that advanced stats are a legitimate way to compare players with similar stat lines? Yet when people mention that giroux's advanced stats blow Stamkos out of the water people just can't accept that maybe giroux is the better player. Man hfboards you slay me.

Can someone post the advanced stats of the top 5 scorers? I expect Giroux to have highest qual comp and most defensive draw percentage.

 

[BillDineen]

The issue is no one has been able to find an instance of a team where scoring chances for/against are not proportional to Fenwick for/against. It's not that "all shots are created equal" - that's obviously a ridiculous and completely untrue statement - it's that the notion some teams are able to control shot quality to a greater degree than others has largely been proven to be false. PDO invariably regresses to the mean long term.

Just because some people might misuse advanced stats is no reason to discount them - seems like that was the rationale behind BoredMan's dismissal of the numbers.

"Just because some people might misuse advanced stats is no reason to discount them" I agree with that 100%.

I do not know where the bold comes from. Where did the data for scoring chances come from? I have heard the Flyers say they keep their own stats as do teams in the video link I posted.

 

[MessierII]

Corsi is the stupidest stat ever I'm pretty sure

 

[NOTENOUGHJTCGOALS]

Advanced Stats aren't meant to be used as absolute gospel, and people who write about/using advanced numbers will tell you that.



That's why it evolves to Fenwick.

Raw Corsi is also good to understand for beginners, but Corsi Rel and Corsi Rel QoC are better indicators because they used other factors.

The reason this stuff gets used as a proxy is because no one can possibly watch all 1230 NHL games let alone watch all 1230 NHL games AND properly evaluate players.





This is the problem Nashville runs into, because they've been proven to be successful at it for years, but it wouldn't translate into the playoffs since it's not the regular season.

http://blogs.thescore.com/nhl/2012/...edicting-nashvilles-regression-five-theories/



http://www.arcticicehockey.com/2011/11/28/2591407/fun-with-pdo

Unless you honestly think Kent Huskins that good, Shot Quality is roughly 11% of the game. Advanced Stats covers the other 89%.

Are these advanced stats useful in predicting the outcome of a single game/series/season? And how far back do they go?

If someone could link to a study showing the best advanced stats for predicting team success in the season/post-season I'd be very interested.

 

[Les Wynan*]

"Just because some people might misuse advanced stats is no reason to discount them" I agree with that 100%.

I do not know where the bold comes from. Where did the data for scoring chances come from? I have heard the Flyers say they keep their own stats as do teams in the video link I posted.

Well it's mostly centered around the fact that no team has exhibited the ability to sustain a PDO (even strength Sh% + even strength SV%) that deviates significantly from the mean of 1000 - the article I linked to has the data behind that. While there isn't specific scoring chance data available per se, it stands to reason that if teams aren't able to drive PDO, there can't be teams that get massively outshot while keeping opposing teams to the outside while they themselves generate high quality chances at a far greater rate than average.

Further evidence is that, over the past four seasons, there's been zero year-to-year correlation in team shooting percentage. So even in the unlikely scenario that some teams are able to sustain a scoring chance differential greater than that of their Fenwick differential, they aren't finishing those extra chances so it makes no difference - but, again, that seems like a pretty far-fetched scenario to me. In terms of actual scoring chance analysis, this is probably the best (only?) look at Fenwick versus scoring chances and the correlation is obviously very high (about 0.9). But that's just a 70-game sample size, collected by one scorer for one team so I wouldn't put a ton of weight into it but it confirms most of the stuff that's been found by looking at shooting and save percentage.