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09-23-2012, 02:42 AM
  #38
Iain Fyffe
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Quote:
Originally Posted by Dalton View Post
It is or should be clear that simply using league gpg to compare players results over eras is in no way accurate.
Accurate? Fair is a better word, I would suggest. There's no accuracy involved.

Quote:
Originally Posted by Dalton View Post
I don't agree that one can state with any confidence that x goals in one era is equivalent to y goals in another.
You can say it with a good degree on confidence. The lower the average goals per game, the greater value each goal has in terms of winning games, which of course is the point of scoring goals in the first place. The number of goals required to add a win for an average team is easily calculated.

Quote:
Originally Posted by Dalton View Post
But looking closer we can see that the top 5, 10 and 20% of skaters last season scored more than the same groups of the 2010-11 season. The top 5% of 2010-11 scored 21.5% of the league's goals. The 2011-12 group scored 23%. The Top 10% of skaters are 39.6% to 36.8% and the top 20% of skaters 63.6% to 60%. Both in favour of the 2011-12 season. Stamkos' 60 goals are not responsible but obviously contributed. However I notice that the difference increases as the groups get larger.
You'll need some more work to develop this idea. Have you considered whether forwards and defencemen should be analyzed separately? Have you considered the effect of ice time (should even out over a large enough number of players, but you never know)?

Quote:
Originally Posted by Dalton View Post
To use the mean to adjust 2010-11 downward would not acurately reflect what happened.
Again, the only accurate thing was what actually happened. I can't see how you can call any adjustment accurate. The adjustment is not to make the numbers more "accurate", just more comparable, or perhaps more meaningful.

Quote:
Originally Posted by Dalton View Post
Perry scored 50 in a season in which his peers scored less overall compared to Malkin who scored his 50 in a season that all his peers scored more. The value of Perry's 50 should be more than Malkin's not less.
Since goals were easier to come by in 2010/11, arguably Perry's 50 goals were worth less than Malkin's, since Malkin's did more to help his team win.

Quote:
Originally Posted by Dalton View Post
I would argue that any formula that uses means ignores the effect of outliers and gives unreliable results compared to calculations that take outliers into account. If you are not talking about using means then I'm not sure how to respond to you since that is what I'm talking about.
That's why I said it works well for the great majority of players. Outliers do not fall within the great majority.

Quote:
Originally Posted by Dalton View Post
To state that gx goals in season sx is comparable to gy goals in season gy just isn't accurate.
You keep saying that, and I still don't know what you mean. Since we're not dealing with true values, I don't see how accuracy is an issue.

However, again, comparing goals in one season, where it takes 5.00 goals to earn a win for your team to another season where it takes 4.00 goals to win a game is certainly valid. The easier goals are to come by, the less value they have in winning games.

Quote:
Originally Posted by Dalton View Post
For what it's worth using percentages Perry would score 48.6 goals last season according the percentage of all the league's goals that he scored or maybe 53 just looking at his percentage of the top 5% of all skaters. Almost 5 goals difference. Adjusting raw data just doesn't work IMHO.
Almost five goals difference is almost nothing. If you assign a large degree of confidence to a 53-goal player being better than a 48-goal player, you're making too fine a distinction.

I can certainly see how from your perspective, your method is more accurate. That does not mean that using means is not accurate, it just means it's somewhat less accurate.

Quote:
Originally Posted by Dalton View Post
I should also point out that for about 70% of the players using a mean would not be acurate because they scored less as a subgroup of the league last year than the previous season. Applying means to adjust 2010-11 players to the lower scoring season of 2011-12 would not be accurate. Their results would be inflated compared to the 2011-12 reality just as Perry's results would be deflated. Means just don't work IMHO.
Inflated by what amount? Is it large enough that mean-based analysis is completely usless? I doubt it.

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