Navigation: Jump to content areas:


Pro Quality. Fan Perspective.
Login-facebook
Around SBN: Are The Orioles Bad Or Unlucky With Their Young Pitching?

Is it Possible to Determine Goaltender True Talent on the PK?

There's a huge amount of year-to-year variation in goaltender performance.  The general consensus is that save percentage converges to true talent levels after approximately four full seasons, though goaltender true talent is rarely stable for four seasons.

A significant portion of the variation in overall save percentage is variation in short-handed save percentage (and, to a much lesser extent, variation in PP save-percentage.)  If a goalie posts a very high SH save percentage one season, should we read anything into it?  Not likely.  This chart shows the regression to the mean of ES and SH save percentage for pairs of one season and two seasons:

 

Years ES SH
1-2 78% 96%
1/2-3/4 64% 93%

 

Basically, Even-Strength save percentage, which is measured over a large number of shots, is a significant predictor of future performance, though it must be heavily-regressed to the mean save percentage.  SH save percentage, on the other hand, is essentially random.  Your best guess of next year's SH save percentage is the league average.  Indeed, last year's even-strength save percentage is a much better predictor of next year's SH save percentage than this year's SH save percentage.  No surprises here - lots of shots, even at even-strength, give us a better estimate of a goalie's talent level than a small number at any other strength.

Comment 15 comments  |  1 recs  | 

Do you like this story?

Comments

Display:

90%+! That’s a pretty wicked regression to the mean there.

All things Thrashers + stats: www.birdwatchersanonymous.com

by The Falconer on Mar 5, 2010 9:51 AM EST reply actions  

And that even includes goaltenders who play behind PK units that don’t change from year-to-year – be they good or bad.

by Hawerchuk on Mar 5, 2010 9:58 AM EST up reply actions  

I got it from NHL.com. You can figure it out at 5-on-5 from the goalie sheets on my site, but nobody ever looks at the goalie stats, so I haven’t put it in there automatically…One of the many things I should do!

Even-strength save percentage is the best measure of a goalie’s ability. I like to use 3 or 4 years of data…

by Hawerchuk on Mar 5, 2010 11:50 AM EST up reply actions  

ES sv% is better than overall sv%?

I’m not questioning, just curious, since you’re reducing your sample size. It would be very interesting, with regards to the Habs’ goaltending situation, if EV save% was the best predictor.

by MathMan on Mar 5, 2010 2:28 PM EST up reply actions  

ES sv% is better than overall sv%?

I would imagine if everyone played the same ratio of EV-to-SH minutes then you would use overall SV%, but since some goalies just get shelled more because their team takes more penalties, overall SV% isn’t too illumintating.

by R O on Mar 5, 2010 3:06 PM EST up reply actions  

Even if the EV/SH ratio was constant, the variation from year to year in SHSV% is much larger than EVSV%.

by edm_euler on Mar 6, 2010 3:37 PM EST up reply actions  

I think that’s because of small sample size.

EVSV% also varies substantially, just not as much as SV%.

It’s all a sample size problem why PKSV% alone can’t be trusted to reflect a goalie’s abilities on the PK. But if every goalie played the same amount of PK minutes then overall SV% might become more useful. Just a bigger sample.

Certainly there might be questions about shot quality on the PK affecting the stat. But shot quality doesn’t appear to look all that big an effect at EV, it’s possible we overestimate its effect on the PK as well.

by R O on Mar 6, 2010 4:36 PM EST up reply actions  

Tyler Dellow covers the randomness of SHSV% (or PPSV%, depending on your perspective) quite nicely, and Scott Reynolds adds to the discussion in a couple of posts.

The variance does come down to small sample size, but because the SHSV% varies so much more than EVSV%, even if the ratio were the same for every goalie EVSV% would still be more stable from year to year and, as this post shows, a better predictor of future performance.

But if the ratio was the same it would make overall SV% a better apples-to-apples comparison among goalies for a given year, so I guess it depends on what you want to do with it, judge how good of a year a goalie had or predict how he’ll do in the future.

by edm_euler on Mar 6, 2010 5:22 PM EST up reply actions  

I look at goalie stats! Bring on the save percentage columns!

Is there a any way to extrapolate the goalie part of PK from ES performance and assign the remainder to the PK unit in front of him. I’m thinking specifically of Vokoun. ES his save percentage computes to 0.938. PK I get 0.847. What “should” his PK be?

by DoctorMyBrainHurts on Mar 5, 2010 9:23 PM EST up reply actions  

Great work. I was thinking about this very issue watching the Caps PK last night. Theo, Neuvy, and Varly seemed to get hosed because Caps PK is so bad (passively passive).

"You ever use smelling salts, every time you type a bad blog?" Brooks Laich

by Carl Putnam on Mar 5, 2010 3:58 PM EST reply actions  

Does this mean Vesa Toskala gets pardoned for his ridiculously bad PK performance earlier this year?

I’m anticipating the answer: Toskala shouldn’t be pardoned for anything.

Bettman's Nightmare: A Blog Where Hockey Aficionados Dismantle That Mighty Empire, One Balsillie at a Time

http://bettmansnightmare.blogspot.com/

by Bettman's Nightmare on Mar 5, 2010 5:24 PM EST reply actions  

Toskala’s still a pretty bad EV goaltender, although some of that has to be that his team has an asinine strategy for defending leads.

If this is a roundabout way to diss the McElhinney-Toskala trade though… well you’re about two days late to the bandwagon doncha think?

by R O on Mar 5, 2010 5:32 PM EST up reply actions  

Toskala got traded?

J/k. No, I really could care less about the trading of backup goaltenders. But it’s funny to hear that some other people did.

The only reason I brought it up is because I recalled Gabe’s previous post on the Leaf’s and their PK.

Bettman's Nightmare: A Blog Where Hockey Aficionados Dismantle That Mighty Empire, One Balsillie at a Time

http://bettmansnightmare.blogspot.com/

by Bettman's Nightmare on Mar 5, 2010 6:44 PM EST up reply actions  

Comments For This Post Are Closed


User Tools

The finest Winnipeg Jets analysis on the internets

FanPosts

Community blog posts and discussion.

Recent FanPosts

Gonzo_fist_2_small
Percentages & PDO: Home and Away
Gonzo_fist_2_small
Scoring Chances Jets vs. Habs Feb 5th
Gonzo_fist_2_small
Missed Shots Stats
Globeatar_small
Entering The Shot Quality Competition
Gonzo_fist_2_small
Jets vs. Rangers Scoring Chances Jan 24th
Rangersblog_small
Ilya Kovalchuk Question
Gonzo_fist_2_small
Updated - Scoring Chance Data since November 3rd
Sharkslogo_small
Scoring Chances - SJS vs WPG - 01/12/12
Sharkslogo_small
Scoring Chances - ANA vs WPG - 12/17/11
Sharkslogo_small
Scoring Chances - PHX vs WPG - 12/01/11

+ New FanPost All FanPosts >


Managers

Hawerchuk_small Hawerchuk

Gary_bettman_bad_dreams_small Bettman's Nightmare

Grapes_small canadian texan

Howe_small TJCAPS

Editors

Ryan_small SO_RyanP

0_small maplestirup

Dsc03339_small Mitch Smith

Jets2_small arby_18

Photo_on_2010-11-10_at_15 paulblawat

Shane_small schernoff

Authors

Small sunnymehta.com

Drurybloodsmall_small Rob L

Bwa-lg_small The Falconer

Small Rob Vollman

Gonzo_fist_2_small Alex Hemsky

Bens_grandpa_small Ben's Grandpa

Dogface_small SnarkSD

Small 7thInningSketch