overpass
Registered User
- Jun 7, 2007
- 5,271
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The answer to the question, is of course, both. But in what degree?
5 vs 5
I used behindthenet.ca's .xls files, with data from the 2007-08 season through the 2010-11 season.
EDIT: See post 22 for updated numbers - I used saved shots instead of total shots for these numbers.
Using the binomial approximation to a normal distribution, I calculated the z-score for each NHL player's on-ice shooting percentage over this time period, where z-score = (On-ice GF - On-Ice SOGF*LgSH%)/(Standard deviation calculated using binomial approximation)
Here are the players with the highest and lowest z-scores
Player | Z-score | 5-on-5 on-ice SH%
SIDNEYCROSBY | 6.42 | 13.3%
HENRIKSEDIN | 5.75 | 12.5%
DANIELSEDIN | 5.22 | 12.3%
MARIANGABORIK | 5.17 | 12.9%
BOBBYRYAN | 5.15 | 12.7%
EVGENIMALKIN | 5.12 | 12.4%
RYANGETZLAF | 4.98 | 12.1%
ILYAKOVALCHUK | 4.93 | 12.2%
COREYPERRY | 4.59 | 11.8%
DANYHEATLEY | 4.54 | 11.8%
JASONSPEZZA | 4.52 | 12.0%
ALEXTANGUAY | 4.36 | 12.1%
NATHANHORTON | 4.29 | 11.8%
ALEXBURROWS | 4.27 | 11.8%
JAROMEIGINLA | 4.27 | 11.5%
RYANWHITNEY | 4.21 | 12.1%
PAULSTASTNY | 4.14 | 11.8%
MARTINST. LOUIS | 4.12 | 11.5%
MIKERIBEIRO | 4.09 | 11.7%
NICKLASBACKSTROM | 4.07 | 11.4%
ALEXANDERSEMIN | 3.97 | 11.7%
PAVELDATSYUK | 3.86 | 11.3%
DARRYLBOYCE | 3.80 | 17.5%
ALEXOVECHKIN | 3.77 | 12.1%
JEFFSCHULTZ | 3.76 | 11.4%
STEVENSTAMKOS | 3.75 | 11.8%
NICLASHAVELID | 3.53 | 12.4%
ALEXANDEROVECHKIN | 3.48 | 11.7%
BRENDENMORROW | 3.48 | 11.6%
JOETHORNTON | 3.43 | 11.1%
Player | Z-score | 5-on-5 on-ice SH%
TRAVISMOEN | -4.09 | 6.0%
SHAWNTHORNTON | -3.91 | 5.8%
COLTONORR | -3.89 | 4.7%
RADEKMARTINEK | -3.79 | 6.3%
ADAMHALL | -3.78 | 5.3%
BRENDANWITT | -3.77 | 5.8%
DEREKMEECH | -3.69 | 4.7%
CRAIGADAMS | -3.66 | 5.7%
RYANHOLLWEG | -3.63 | 2.6%
DONALDBRASHEAR | -3.58 | 4.6%
STEPHANEVEILLEUX | -3.49 | 6.0%
JEFFTAMBELLINI | -3.45 | 5.9%
ANDYGREENE | -3.43 | 6.8%
NATETHOMPSON | -3.37 | 5.8%
RODPELLEY | -3.33 | 4.8%
TODDMARCHANT | -3.27 | 6.3%
SAMUELPAHLSSON | -3.23 | 6.5%
RAITISIVANANS | -3.19 | 4.5%
FREDRIKSJOSTROM | -3.19 | 6.3%
TIMSTAPLETON | -3.19 | 3.6%
DANIELWINNIK | -3.12 | 6.7%
SCOTTGOMEZ | -3.09 | 7.2%
ANTTIPIHLSTROM | -3.06 | 4.0%
TOMWANDELL | -3.06 | 5.5%
ANDREWMURRAY | -3.05 | 5.8%
THOMASPOCK | -2.90 | 4.3%
JAMIEMCGINN | -2.90 | 5.7%
ANDREWPETERS | -2.88 | 2.5%
MIKEWEAVER | -2.86 | 7.0%
DALLASDRAKE | -2.82 | 3.8%
Generally speaking we see skilled players outperforming the league average and "less skilled" NHL players underperforming the league average in on-ice shooting percentage.
Taking the standard deviation of the z-scores, I get 1.47. If random variation was the only factor, the standard deviation of the z-scores would be 1.00.
Following the process from this blog post:
Step 7: 768
Step 8: 0.54
Step 9: 657
So, given a player's on-ice shooting percentage from 2007-08 to 2010-11, the best predictor of his 2011-12 on-ice shooting percentage is his 2007-08 through 2010-11 shooting percentage plus 657 shots at a league average shooting percentage. Because Sidney Crosby was on the ice for 1867 shots at a 13.3 SH%, his predicted 2011-12% would be 12.2%.
Best and worst predicted 2011-12 5 vs 5 on-ice shooting percentages
Player | Predicted 5vs5 on-ice SH%
SIDNEYCROSBY | 12.2%
HENRIKSEDIN | 11.7%
MARIANGABORIK | 11.7%
BOBBYRYAN | 11.6%
EVGENIMALKIN | 11.5%
DANIELSEDIN | 11.5%
ILYAKOVALCHUK | 11.4%
RYANGETZLAF | 11.4%
JASONSPEZZA | 11.2%
ALEXTANGUAY | 11.2%
Player | Predicted 5vs5 on-ice SH%
COLTONORR | 6.8%
TRAVISMOEN | 6.9%
ADAMHALL | 6.9%
SHAWNTHORNTON | 6.9%
DEREKMEECH | 7.0%
BRENDANWITT | 7.0%
CRAIGADAMS | 7.0%
DONALDBRASHEAR | 7.0%
RADEKMARTINEK | 7.1%
STEPHANEVEILLEUX | 7.1%
I'll see if I can get the 2011-12 data to test the predictions.
5 vs 5
I used behindthenet.ca's .xls files, with data from the 2007-08 season through the 2010-11 season.
EDIT: See post 22 for updated numbers - I used saved shots instead of total shots for these numbers.
Using the binomial approximation to a normal distribution, I calculated the z-score for each NHL player's on-ice shooting percentage over this time period, where z-score = (On-ice GF - On-Ice SOGF*LgSH%)/(Standard deviation calculated using binomial approximation)
Here are the players with the highest and lowest z-scores
SIDNEYCROSBY | 6.42 | 13.3%
HENRIKSEDIN | 5.75 | 12.5%
DANIELSEDIN | 5.22 | 12.3%
MARIANGABORIK | 5.17 | 12.9%
BOBBYRYAN | 5.15 | 12.7%
EVGENIMALKIN | 5.12 | 12.4%
RYANGETZLAF | 4.98 | 12.1%
ILYAKOVALCHUK | 4.93 | 12.2%
COREYPERRY | 4.59 | 11.8%
DANYHEATLEY | 4.54 | 11.8%
JASONSPEZZA | 4.52 | 12.0%
ALEXTANGUAY | 4.36 | 12.1%
NATHANHORTON | 4.29 | 11.8%
ALEXBURROWS | 4.27 | 11.8%
JAROMEIGINLA | 4.27 | 11.5%
RYANWHITNEY | 4.21 | 12.1%
PAULSTASTNY | 4.14 | 11.8%
MARTINST. LOUIS | 4.12 | 11.5%
MIKERIBEIRO | 4.09 | 11.7%
NICKLASBACKSTROM | 4.07 | 11.4%
ALEXANDERSEMIN | 3.97 | 11.7%
PAVELDATSYUK | 3.86 | 11.3%
DARRYLBOYCE | 3.80 | 17.5%
ALEXOVECHKIN | 3.77 | 12.1%
JEFFSCHULTZ | 3.76 | 11.4%
STEVENSTAMKOS | 3.75 | 11.8%
NICLASHAVELID | 3.53 | 12.4%
ALEXANDEROVECHKIN | 3.48 | 11.7%
BRENDENMORROW | 3.48 | 11.6%
JOETHORNTON | 3.43 | 11.1%
TRAVISMOEN | -4.09 | 6.0%
SHAWNTHORNTON | -3.91 | 5.8%
COLTONORR | -3.89 | 4.7%
RADEKMARTINEK | -3.79 | 6.3%
ADAMHALL | -3.78 | 5.3%
BRENDANWITT | -3.77 | 5.8%
DEREKMEECH | -3.69 | 4.7%
CRAIGADAMS | -3.66 | 5.7%
RYANHOLLWEG | -3.63 | 2.6%
DONALDBRASHEAR | -3.58 | 4.6%
STEPHANEVEILLEUX | -3.49 | 6.0%
JEFFTAMBELLINI | -3.45 | 5.9%
ANDYGREENE | -3.43 | 6.8%
NATETHOMPSON | -3.37 | 5.8%
RODPELLEY | -3.33 | 4.8%
TODDMARCHANT | -3.27 | 6.3%
SAMUELPAHLSSON | -3.23 | 6.5%
RAITISIVANANS | -3.19 | 4.5%
FREDRIKSJOSTROM | -3.19 | 6.3%
TIMSTAPLETON | -3.19 | 3.6%
DANIELWINNIK | -3.12 | 6.7%
SCOTTGOMEZ | -3.09 | 7.2%
ANTTIPIHLSTROM | -3.06 | 4.0%
TOMWANDELL | -3.06 | 5.5%
ANDREWMURRAY | -3.05 | 5.8%
THOMASPOCK | -2.90 | 4.3%
JAMIEMCGINN | -2.90 | 5.7%
ANDREWPETERS | -2.88 | 2.5%
MIKEWEAVER | -2.86 | 7.0%
DALLASDRAKE | -2.82 | 3.8%
Generally speaking we see skilled players outperforming the league average and "less skilled" NHL players underperforming the league average in on-ice shooting percentage.
Taking the standard deviation of the z-scores, I get 1.47. If random variation was the only factor, the standard deviation of the z-scores would be 1.00.
Following the process from this blog post:
Step 1: Figure out how much one standard deviation is based on a binomial distribution. Vokoun faced 4249 shots, and the league average save percentage was .920, so one SD is sqrt (.92*.08/4249) = .0042.
Step 2: Figure out how much away you are from the mean. Vokoun’s save percentage was .931, and so was +.0108 from the mean.
Step 3: Figure out how many SD that is. .0108/.0042 = 2.59. That’s his z-score.
Step 4: Do it for all the goalies. (Thomas is 2.57, Luongo is 2.53… Holmqvist is -3.11, Raycroft is -2.34).
Step 5: Find the standard deviation of all the z-scores. In this case, for these 55 goalies, it’s 1.38.
Step 6: Rejoice if the number is substantially higher than 1.00. Happiness sets in at 1.10. You did good at 1.20. If you get 1.40, you’ve definitely found something.
Step 7: Figure out the average number of opportunities for each player. In this case, the average shots faced was 2665.
Step 8: Do this: 1 - 1/1.38^2 = 0.47. That’s your r or r-squared. (Longer story later. Just call it r for now.) That 1.38 was from Step 6.
Step 9: Do this: (1-r)/r * 2665. We get 2969. The 2665 is from Step 7.
That’s the key number. 2969. Let’s call it 3000. That’s how much you use to regress a goalie’s performance. You add 3000 shots of league average performance. So Vokoun’s 4249 shots at .931 save percentage gets added to 3000 shots at .920 save percentage for a best-estimate true talent level of .926. Holmqvist’s .900 with 1809 shots becomes .912. So, the observed difference between the two goalies (.031 saves per shot) becomes a true difference of .014.
Step 7: 768
Step 8: 0.54
Step 9: 657
So, given a player's on-ice shooting percentage from 2007-08 to 2010-11, the best predictor of his 2011-12 on-ice shooting percentage is his 2007-08 through 2010-11 shooting percentage plus 657 shots at a league average shooting percentage. Because Sidney Crosby was on the ice for 1867 shots at a 13.3 SH%, his predicted 2011-12% would be 12.2%.
Best and worst predicted 2011-12 5 vs 5 on-ice shooting percentages
SIDNEYCROSBY | 12.2%
HENRIKSEDIN | 11.7%
MARIANGABORIK | 11.7%
BOBBYRYAN | 11.6%
EVGENIMALKIN | 11.5%
DANIELSEDIN | 11.5%
ILYAKOVALCHUK | 11.4%
RYANGETZLAF | 11.4%
JASONSPEZZA | 11.2%
ALEXTANGUAY | 11.2%
COLTONORR | 6.8%
TRAVISMOEN | 6.9%
ADAMHALL | 6.9%
SHAWNTHORNTON | 6.9%
DEREKMEECH | 7.0%
BRENDANWITT | 7.0%
CRAIGADAMS | 7.0%
DONALDBRASHEAR | 7.0%
RADEKMARTINEK | 7.1%
STEPHANEVEILLEUX | 7.1%
I'll see if I can get the 2011-12 data to test the predictions.
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