THE BOOK--Playing The Percentages In Baseball

Wednesday, November 24, 2010

The dirty secret: WAR aging path for great players

By Tangotiger, 03:15 PM

All players who were
- born between 1895 and 1968
- over the preceding 4 seasons had at least 1500 PA, with a WAR/700PA rate of 4+ wins
- in the preceding season had at least 500 PA, with a WAR/700PA rate of 4+ wins

Age refers to his age entering that fifth year.

WAR4 is his WAR for the preceding 4 years and PA4 is the PA for the preceding 4 years. WAR/PA is WAR4 divided by PA4 times 700.

Next1 is his total WAR in the next year. Next2 is his WAR in the second year, etc. Avg5 is the average of Next1 through Next5.

Data from Rally’s WAR database.

Age    n    WAR4    PA4    WAR/PA     Next1    Next2    Next3    Next4    Next5    Avg5 
25    15     19     2106     6.4      6.0      7.1      6.3      6.4      5.7      6.3 
26    54     18     2150     5.9      5.3      5.8      5.1      5.0      4.8      5.2 
27    85     19     2246     5.9      5.3      5.2      4.6      4.2      3.7      4.6 
28    121     20     2297     6.0      5.1      4.4      4.2      3.7      3.9      4.2 
29    165     19     2295     5.8      4.2      4.0      3.5      3.6      3.1      3.7 
30    159     20     2350     6.0      4.5      3.8      4.0      3.5      3.0      3.8 
31    164     20     2354     6.0      3.9      4.0      3.5      2.9      2.2      3.3 
32    166     20     2376     5.8      4.4      3.7      3.1      2.4      1.6      3.1 
33    155     20     2374     5.9      4.1      3.7      2.7      2.1      1.6      2.9

The “dirty secret” is that great young players will perform better than other great older players. Great players at age 25, who until then averaged a WAR of 6.4 per 700 PA averaged 6.3 WAR per season (and at much less than 700 PA) over the next 5 seasons.

***

Other interesting tidbits: the great 25 year olds peaked at 26. The great 26 year olds peaked at 27.

Even though the great 27 year olds and 33 year olds both entered their season with the same level of past performance over the preceding 4 seasons (5.9 WAR per 700 PA, close to 2300 PA over the last 4 seasons), the younger group earned 1 to 2 more wins in each of the next 5 seasons. The average was an astounding 1.7 more wins per season, and that’s just a 6 year gap in age.

• Sabermetrics • Forecasting

#1 Tangotiger (see all posts) 2010/11/24 (Wed) @ 16:03

Note, click on the title to see the full chart:
http://www.insidethebook.com/ee/index.php/site/article/the_dirty_secret_war_aging_path_for_great_players/

***

Another good one? If you take the simple average of the players from age 27 through 35, you get the following WAR for each of the next 5 years:
4.4
3.9
3.4
2.9
2.4

That is a drop of exactly 0.5 wins per season. This is the rule-of-thumb WAR aging I’ve been using for a few years now.

#2 David Pinto (see all posts) 2010/11/24 (Wed) @ 16:49

Great stuff.

#3 (see all posts) 2010/11/24 (Wed) @ 23:13

Like.

#4 Guy (see all posts) 2010/11/25 (Thu) @ 01:23

Neat. Could you post the same table showing WAR/700 PA for the five seasons, rather than total WAR. Would be nice to disaggregate rate performance from PT.

I don’t think you can say anything meaningful about how these cohorts “peaked.” First, you don’t show us their earlier annual performances --they may have peaked at 23 or 24. Also, the requirement of a strong season in the 4th year potentially biases the sample in favor of those on an upward slope. (Increasingly, I’m skeptical of the whole “peak” concept. At least for these good players, I think there’s basically a plateau from 23 to 28, then a decline.)

#5 Neil S. (see all posts) 2010/11/25 (Thu) @ 16:49

Maybe I’m misunderstanding the original assertion, but wasn’t it actually claiming that great young players perform more poorly on the downside of their career? (And even if this wasn’t the original claim, I’m interested to see if this is the case...)

So i guess my question, then, is how does the great 25 year-old perform against the great 30 year-old in their (and i’ll just choose these numbers arbitrarily) year 33-35 seasons? And does the great 25 year-old retire, on average, at a different age than the great 30 year-old?

#6 Tangotiger (see all posts) 2010/11/25 (Thu) @ 20:20

Neil: no, that couldn’t have been the original assertion. Who cares how good your 25 year old is at age 30-34? You signed him at ages 25-29 for 5 years. After that, he’s a free agent, and you don’t derive any benefit from his talent at ages 30-34.

In any case, check out my chart above. The 25 year old at age 29 is still fantastic. Way better than 29 year old at age 29.

#7 Neil S (see all posts) 2010/11/25 (Thu) @ 23:16

Tango wrote: “Who cares how good your 25 year old is at age 30-34?”

Me, I guess.

#8 Tangotiger (see all posts) 2010/11/26 (Fri) @ 15:23

Guy, WAR/700PA

25     6.5      6.7      6.1      5.9      6.0 
26     6.1      6.1      5.5      5.4      5.0 
27     6.0      5.5      5.4      5.0      5.3 
28     5.1      5.0      4.6      4.9      4.3 
29     5.5      5.0      5.1      4.7      4.4 
30     5.0      5.2      4.8      4.3      3.7 
31     5.3      4.8      4.3      3.9      3.1 
32     5.1      4.9      4.1      3.5      3.3 
33     5.2      4.4      3.8      3.6      3.5

As you can see, not much changes. The age 25 guys peak at 26, the age 26 guys peak at 26/27 (unless earlier).

FWIW, there was also only 15 players at age 24, and they peaked at age 25.

#9 MookieTheCat (see all posts) 2010/11/27 (Sat) @ 00:46

This might be a stupid question, but this site has taught me a lot as I lurked about the details of advanced metrics so I though I’d give it a go. How do you get WAR figures for guys prior to the age of available film? While hitting seems clear to me, the defensive portion seems difficult to estimate in retrospect.

#10 Tangotiger (see all posts) 2010/11/27 (Sat) @ 09:53

"difficult. not impossible.”

“good.”

***

They tracked PO + A + E + Games + starting lineup by player and hits allowed by game. We estimate everything else.

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THE BOOK--Playing The Percentages In Baseball

Wednesday, November 24, 2010

The dirty secret: WAR aging path for great players

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