Percentage growth by players of different ages?

[Music2004Man]

I remember seeing people post in here about how players show percentage points of growth approximately up to the age of 27 and at that time they start to decline. I'm looking for a list in somewhat the same format as this......

22 +5%
23 +4%
24 +3%
25 +2%
26 +1%
27
28 -1%
etc.

I know that the numbers probably aren't close to right and aren't as cut and dry as this but if anyone understands what I'm looking for can you help me out. I feel like Tavish or GotoWarAgnes might have posted these numbers before. I'm looking to add it to my spreadsheet so thanks for the help.

[chadlincoln]

I remember seeing people post in here about how players show percentage points of growth approximately up to the age of 27 and at that time they start to decline. I'm looking for a list in somewhat the same format as this......

22 +5%
23 +4%
24 +3%
25 +2%
26 +1%
27
28 -1%
etc.

I know that the numbers probably aren't close to right and aren't as cut and dry as this but if anyone understands what I'm looking for can you help me out. I feel like Tavish or GotoWarAgnes might have posted these numbers before. I'm looking to add it to my spreadsheet so thanks for the help.

It might be the hair, but one of the biggest look changes is Miguel Cabrera IMO. I hadn't seem him in a while then I saw him on Sportscenter. He's really looking like Manny Jr.

[Tavish]

Tango's peak evaluation might help.

[LooseCannon]

Seems pretty accurate (Tango one) Is it really true about the stars of the game?

[Music2004Man]

Thanks Tavish,

That's what I was looking for.

[GotowarMissAgnes]

Some other good sources:

JC Bradbury's studies (click on the Age and Hitting Links)
http://www.sabernomics.com/

Baseball Notebook's David Luciani's study
http://www.baseballnotebook.com/essay.a ... %20Hitting

Keith Woolner's look
http://www.stathead.com/bbeng/woolner/peakage.htm

A brief comment on Bill James' original 1982 study can be found here:
http://baseballanalysts.com/archives/20 ... rom_17.php
at the bottom of the page

Ken Cherven has done some recent work on this and presented it at SABR 2005 in August
http://64.233.167.104/search?q=cache:P0 ... ball&hl=en
I can't seem to get the powerpoint to work, so the link is an HTML version of his slides.

If you really like fancy stats, Jim Albert's study is for you
http://bayes.bgsu.edu/papers/career_trajectory.pdf

And Medline even shows a study
http://www.ncbi.nlm.nih.gov/entrez/quer ... query_hl=3


Given Roy Fair's skills, it will be interesting to see this full study when it is published...
http://ideas.repec.org/p/cwl/cwldpp/153 ... /2005D.PDF
It also has a wonderful review of possible juicing based on looking at players who out-performed what his model predicted.

In general, I would say that people often misinterpret the early studies, which really never pinpointed a single age as THE peak. It's much more accurate to say that they indicated that the vast majority of players peaked between ages 25 and 29, with 27 the most common peak, by a whisker. Furthermore, all the studies show that peak age differs for different statistics: batting average and SBs tend to peak before 27, power stats like homers and doubles peak right around 27, and stats like walks and OBP tend to peak after age 30.

The more recent studies, like Bradbury's and Cherven's suggest two important things. First, the peak seems to be shifting a little later, with maybe 26 to 31 as a better peak window for today's players. They also suggest that players are declining more slowly after the peak. There's lots of speculation about causes, including misreported ages in early datasets, steroids, better training, and a bunch of others.