Changes in WAR and Playing Time Based on Age Since 1980
In my piece last week discussing the age-related demographics of the Trade Value Series, I included multiple graphs showing how baseball has changed over the years with respect to the quality and quantity of the contributions of younger and older players in the game. This is is one of the graphs from that piece:
This graph, and the others like it in the post, did a good job of showing age-related changes. But I thought there might be interest in the data underlying those graphs, data that would have been much too cumbersome to include in the piece. Below is the data that drove those graphs; it even breaks the ages down into smaller subsets. The numbers in all of the headers below represent player ages.
First, here’s the share of position player WAR by age since 1980. In the graphs included in the piece, I used five-year rolling averages to better assess trends, and only used three age groups. The table below shows the individual season shares, with the prime years and aging years broken down into more groups:
Year | 24 and Under WAR | 25-27 WAR | 28-30 WAR | 31-33 WAR | 34+ WAR |
---|---|---|---|---|---|
1980 | 14.0% | 30.7% | 27.3% | 21.1% | 6.8% |
1981 | 13.2% | 31.1% | 25.9% | 18.3% | 11.5% |
1982 | 14.4% | 29.9% | 19.8% | 22.6% | 13.3% |
1983 | 14.6% | 32.4% | 23.3% | 15.1% | 14.6% |
1984 | 21.8% | 26.5% | 27.3% | 14.6% | 9.9% |
1985 | 13.5% | 31.9% | 26.6% | 11.9% | 16.1% |
1986 | 11.6% | 34.4% | 24.6% | 15.7% | 13.7% |
1987 | 15.9% | 35.8% | 23.3% | 15.1% | 9.9% |
1988 | 19.8% | 29.1% | 25.9% | 17.9% | 7.2% |
1989 | 12.0% | 28.9% | 33.9% | 17.8% | 7.3% |
1990 | 10.7% | 33.3% | 30.1% | 15.8% | 10.0% |
1991 | 12.0% | 29.3% | 29.9% | 18.1% | 10.6% |
1992 | 17.8% | 28.5% | 25.8% | 19.9% | 8.0% |
1993 | 12.3% | 31.7% | 29.1% | 17.2% | 9.7% |
1994 | 4.9% | 32.7% | 32.7% | 16.0% | 13.6% |
1995 | 6.8% | 31.9% | 34.3% | 17.9% | 9.1% |
1996 | 8.3% | 21.6% | 31.8% | 27.5% | 10.8% |
1997 | 9.0% | 20.2% | 36.3% | 24.8% | 9.7% |
1998 | 14.8% | 18.9% | 30.2% | 23.6% | 12.5% |
1999 | 8.3% | 28.8% | 23.4% | 24.5% | 15.0% |
2000 | 8.4% | 27.2% | 28.8% | 20.0% | 15.6% |
2001 | 7.3% | 29.3% | 29.7% | 19.8% | 14.0% |
2002 | 7.0% | 28.2% | 29.5% | 20.0% | 15.2% |
2003 | 7.8% | 30.8% | 26.1% | 18.4% | 16.9% |
2004 | 11.5% | 24.4% | 33.6% | 16.2% | 14.3% |
2005 | 10.4% | 26.1% | 33.5% | 19.9% | 10.1% |
2006 | 15.1% | 25.5% | 30.8% | 16.5% | 12.1% |
2007 | 20.4% | 24.8% | 23.7% | 22.0% | 9.0% |
2008 | 15.8% | 26.9% | 27.8% | 15.6% | 13.9% |
2009 | 12.4% | 33.5% | 26.1% | 16.3% | 11.7% |
2010 | 15.3% | 28.9% | 26.3% | 18.1% | 11.5% |
2011 | 15.2% | 34.0% | 31.5% | 10.5% | 8.7% |
2012 | 10.9% | 29.1% | 35.5% | 16.7% | 7.8% |
2013 | 15.1% | 33.4% | 31.6% | 13.2% | 6.7% |
2014 | 17.6% | 27.4% | 30.8% | 17.2% | 7.0% |
2015 | 21.5% | 27.4% | 28.0% | 16.4% | 6.7% |
2016 | 21.1% | 27.7% | 27.9% | 16.3% | 7.0% |
2017 | 19.1% | 33.8% | 26.6% | 15.9% | 4.5% |
2018 | 16.8% | 38.2% | 28.1% | 9.4% | 7.5% |
2019 | 18.1% | 36.6% | 29.6% | 11.2% | 4.4% |
Average | 13.6% | 29.5% | 28.7% | 17.6% | 10.6% |
Here’s the share of plate appearances:
Year | 24 and Under PA | 25-27 PA | 28-30 PA | 31-33 PA | 34+ PA |
---|---|---|---|---|---|
1980 | 16.3% | 29.6% | 26.7% | 18.7% | 8.8% |
1981 | 13.7% | 28.9% | 27.0% | 19.8% | 10.6% |
1982 | 16.1% | 27.6% | 22.8% | 20.7% | 12.8% |
1983 | 17.4% | 27.0% | 23.9% | 16.4% | 15.3% |
1984 | 19.8% | 25.0% | 23.4% | 15.7% | 16.0% |
1985 | 15.6% | 29.2% | 23.6% | 13.0% | 18.5% |
1986 | 16.1% | 30.8% | 22.2% | 14.3% | 16.7% |
1987 | 18.1% | 32.2% | 22.4% | 14.0% | 13.3% |
1988 | 17.1% | 31.0% | 26.0% | 14.7% | 11.1% |
1989 | 14.2% | 29.9% | 29.1% | 17.0% | 9.7% |
1990 | 13.3% | 30.5% | 29.5% | 15.4% | 11.3% |
1991 | 15.2% | 29.7% | 27.4% | 16.5% | 11.3% |
1992 | 18.0% | 27.5% | 25.2% | 19.4% | 9.9% |
1993 | 14.6% | 30.8% | 27.0% | 17.1% | 10.5% |
1994 | 10.3% | 31.4% | 29.0% | 18.1% | 11.2% |
1995 | 12.6% | 31.5% | 26.8% | 17.3% | 11.8% |
1996 | 12.5% | 27.2% | 27.2% | 21.4% | 11.6% |
1997 | 11.9% | 26.1% | 28.9% | 21.0% | 12.0% |
1998 | 16.2% | 22.6% | 27.8% | 20.2% | 13.2% |
1999 | 15.1% | 24.9% | 25.1% | 19.9% | 15.0% |
2000 | 13.3% | 25.0% | 24.7% | 21.1% | 15.8% |
2001 | 11.7% | 28.8% | 23.7% | 19.6% | 16.1% |
2002 | 11.6% | 26.8% | 26.5% | 19.0% | 16.2% |
2003 | 10.0% | 29.5% | 25.7% | 18.4% | 16.2% |
2004 | 11.2% | 25.3% | 29.5% | 17.7% | 16.4% |
2005 | 12.5% | 23.0% | 28.1% | 20.5% | 15.9% |
2006 | 15.3% | 22.6% | 26.6% | 18.1% | 17.4% |
2007 | 16.3% | 24.4% | 22.3% | 22.2% | 14.9% |
2008 | 17.4% | 25.7% | 23.1% | 18.0% | 15.8% |
2009 | 11.9% | 30.5% | 24.3% | 19.4% | 13.8% |
2010 | 14.6% | 28.8% | 23.4% | 16.8% | 16.3% |
2011 | 15.4% | 28.8% | 24.3% | 16.7% | 14.9% |
2012 | 13.7% | 28.9% | 28.2% | 17.0% | 12.2% |
2013 | 16.0% | 29.7% | 25.7% | 16.4% | 12.1% |
2014 | 17.1% | 27.0% | 27.1% | 18.3% | 10.6% |
2015 | 17.4% | 26.3% | 26.0% | 20.0% | 10.3% |
2016 | 16.3% | 28.4% | 26.2% | 19.2% | 9.9% |
2017 | 17.7% | 30.5% | 23.2% | 18.4% | 10.2% |
2018 | 16.2% | 33.3% | 24.5% | 15.9% | 10.1% |
2019 | 15.6% | 33.5% | 25.7% | 16.3% | 8.9% |
Average | 14.9% | 28.3% | 25.8% | 18.0% | 13.1% |
And here’s the quality of those plate appearances with WAR per 600 plate appearances.
Year | 24 and Under WAR/600 | 25-27 WAR/600 PA | 28-30 WAR/600 PA | 31-33 WAR/600 PA | 34+ WAR/600 PA |
---|---|---|---|---|---|
1980 | 1.6 | 1.9 | 1.9 | 2.1 | 1.4 |
1981 | 1.8 | 2.0 | 1.8 | 1.7 | 2.0 |
1982 | 1.6 | 2.0 | 1.6 | 2.0 | 1.9 |
1983 | 1.6 | 2.2 | 1.8 | 1.7 | 1.8 |
1984 | 2.0 | 2.0 | 2.1 | 1.7 | 1.1 |
1985 | 1.6 | 2.0 | 2.1 | 1.7 | 1.6 |
1986 | 1.3 | 2.1 | 2.0 | 2.0 | 1.5 |
1987 | 1.6 | 2.0 | 1.9 | 2.0 | 1.4 |
1988 | 2.1 | 1.7 | 1.9 | 2.3 | 1.2 |
1989 | 1.6 | 1.8 | 2.2 | 1.9 | 1.4 |
1990 | 1.5 | 2.0 | 1.9 | 1.9 | 1.6 |
1991 | 1.5 | 1.8 | 2.0 | 2.0 | 1.7 |
1992 | 1.8 | 1.9 | 1.9 | 1.9 | 1.5 |
1993 | 1.5 | 1.9 | 2.0 | 1.8 | 1.7 |
1994 | 0.9 | 1.9 | 2.0 | 1.6 | 2.2 |
1995 | 1.0 | 1.8 | 2.3 | 1.9 | 1.4 |
1996 | 1.2 | 1.4 | 2.1 | 2.3 | 1.7 |
1997 | 1.4 | 1.4 | 2.3 | 2.1 | 1.5 |
1998 | 1.7 | 1.5 | 2.0 | 2.1 | 1.7 |
1999 | 1.0 | 2.1 | 1.7 | 2.2 | 1.8 |
2000 | 1.1 | 2.0 | 2.1 | 1.7 | 1.8 |
2001 | 1.1 | 1.9 | 2.3 | 1.8 | 1.6 |
2002 | 1.1 | 1.9 | 2.0 | 1.9 | 1.7 |
2003 | 1.4 | 1.9 | 1.8 | 1.8 | 1.9 |
2004 | 1.9 | 1.7 | 2.1 | 1.7 | 1.6 |
2005 | 1.5 | 2.1 | 2.2 | 1.8 | 1.2 |
2006 | 1.8 | 2.1 | 2.1 | 1.7 | 1.3 |
2007 | 2.3 | 1.8 | 1.9 | 1.8 | 1.1 |
2008 | 1.7 | 1.9 | 2.2 | 1.6 | 1.6 |
2009 | 1.9 | 2.0 | 2.0 | 1.5 | 1.6 |
2010 | 1.9 | 1.8 | 2.1 | 2.0 | 1.3 |
2011 | 1.8 | 2.2 | 2.4 | 1.2 | 1.1 |
2012 | 1.5 | 1.9 | 2.3 | 1.8 | 1.2 |
2013 | 1.7 | 2.1 | 2.3 | 1.5 | 1.0 |
2014 | 1.9 | 1.9 | 2.1 | 1.7 | 1.2 |
2015 | 2.3 | 1.9 | 2.0 | 1.5 | 1.2 |
2016 | 2.4 | 1.8 | 2.0 | 1.6 | 1.3 |
2017 | 2.0 | 2.0 | 2.1 | 1.6 | 0.8 |
2018 | 1.9 | 2.1 | 2.1 | 1.1 | 1.4 |
2019 | 2.1 | 2.0 | 2.1 | 1.3 | 0.9 |
Average | 1.6 | 1.9 | 2.0 | 1.8 | 1.5 |
Pitchers were only touched on in my piece because the trends weren’t as striking as with position players, but the table below shows the pitcher share of WAR by age over the years:
Season | 24 and Under WAR | 25-27 WAR | 28-30 WAR | 31-33 WAR | 34+ WAR |
---|---|---|---|---|---|
1980 | 24.1% | 26.2% | 21.2% | 11.7% | 16.9% |
1981 | 20.9% | 28.1% | 20.7% | 12.1% | 18.1% |
1982 | 18.2% | 30.7% | 19.9% | 12.1% | 19.1% |
1983 | 18.4% | 29.6% | 27.2% | 9.3% | 15.6% |
1984 | 21.6% | 29.3% | 26.4% | 9.9% | 12.8% |
1985 | 22.2% | 29.7% | 23.0% | 12.6% | 12.5% |
1986 | 20.4% | 31.8% | 20.6% | 16.0% | 11.2% |
1987 | 19.2% | 26.8% | 23.9% | 18.4% | 11.7% |
1988 | 18.6% | 31.7% | 20.3% | 16.8% | 12.7% |
1989 | 17.3% | 29.0% | 23.8% | 17.4% | 12.4% |
1990 | 17.2% | 34.5% | 21.0% | 15.4% | 11.9% |
1991 | 19.7% | 29.0% | 24.8% | 14.2% | 12.3% |
1992 | 17.4% | 31.6% | 24.4% | 12.5% | 14.0% |
1993 | 13.7% | 32.0% | 29.1% | 15.1% | 10.0% |
1994 | 13.1% | 30.4% | 27.0% | 23.4% | 6.1% |
1995 | 10.5% | 30.3% | 29.7% | 19.3% | 10.2% |
1996 | 12.8% | 24.6% | 30.9% | 21.0% | 10.6% |
1997 | 14.9% | 25.3% | 28.6% | 15.7% | 15.5% |
1998 | 12.9% | 25.4% | 24.9% | 21.2% | 15.7% |
1999 | 16.9% | 25.9% | 19.9% | 21.7% | 15.5% |
2000 | 16.1% | 22.4% | 25.7% | 17.3% | 18.5% |
2001 | 22.0% | 18.0% | 25.8% | 15.6% | 18.6% |
2002 | 17.1% | 27.4% | 22.1% | 14.2% | 19.2% |
2003 | 18.2% | 28.7% | 21.7% | 14.8% | 16.7% |
2004 | 12.2% | 31.7% | 24.1% | 15.1% | 16.9% |
2005 | 18.5% | 27.8% | 22.9% | 14.9% | 15.8% |
2006 | 20.3% | 28.2% | 23.4% | 10.0% | 18.1% |
2007 | 17.0% | 28.4% | 27.9% | 11.8% | 14.8% |
2008 | 23.0% | 30.2% | 23.1% | 15.6% | 8.1% |
2009 | 17.2% | 38.7% | 20.6% | 13.9% | 9.6% |
2010 | 20.2% | 37.3% | 17.6% | 15.7% | 9.2% |
2011 | 17.7% | 36.2% | 23.9% | 9.7% | 12.4% |
2012 | 18.0% | 32.4% | 23.7% | 12.6% | 13.3% |
2013 | 18.0% | 34.6% | 26.3% | 10.4% | 10.6% |
2014 | 15.6% | 33.0% | 33.7% | 9.2% | 8.4% |
2015 | 15.7% | 36.8% | 25.7% | 14.7% | 7.1% |
2016 | 17.2% | 33.8% | 27.0% | 17.0% | 5.0% |
2017 | 17.1% | 26.1% | 31.2% | 19.0% | 6.6% |
2018 | 15.0% | 29.0% | 30.2% | 16.8% | 9.1% |
2019 | 12.1% | 29.3% | 27.4% | 18.7% | 12.4% |
Average | 17.5% | 29.8% | 24.8% | 15.1% | 12.9% |
If you eyeball the data, it certainly looks like older pitchers are more valuable as the run-scoring environment tips in batters’ favor. It’s possible the younger pitchers simply aren’t quite as ready for the step up to the big leagues when offense is at its highest. The next table shows the share of innings pitched by age group.
Season | 24 and Under IP | 25-27 IP | 28-30 IP | 31-33 IP | 34+ IP |
---|---|---|---|---|---|
1980 | 22.1% | 30.0% | 22.5% | 12.7% | 12.6% |
1981 | 17.9% | 33.4% | 20.9% | 13.7% | 14.1% |
1982 | 16.4% | 34.0% | 21.9% | 13.4% | 14.3% |
1983 | 17.6% | 31.5% | 24.7% | 12.1% | 14.2% |
1984 | 18.7% | 31.1% | 26.1% | 12.0% | 12.1% |
1985 | 19.0% | 30.3% | 24.6% | 13.8% | 12.3% |
1986 | 19.1% | 31.6% | 21.4% | 16.0% | 11.9% |
1987 | 20.4% | 29.0% | 22.8% | 17.2% | 10.7% |
1988 | 18.5% | 28.9% | 23.0% | 17.4% | 12.1% |
1989 | 17.0% | 27.3% | 25.6% | 16.7% | 13.4% |
1990 | 17.0% | 29.5% | 26.2% | 16.1% | 11.2% |
1991 | 19.1% | 29.9% | 23.5% | 15.8% | 11.7% |
1992 | 17.5% | 30.1% | 24.5% | 13.9% | 14.0% |
1993 | 17.3% | 32.0% | 25.2% | 13.9% | 11.7% |
1994 | 15.8% | 30.6% | 24.8% | 18.0% | 10.8% |
1995 | 16.6% | 32.0% | 26.7% | 15.0% | 9.7% |
1996 | 16.4% | 30.2% | 28.3% | 15.9% | 9.1% |
1997 | 17.3% | 29.9% | 26.1% | 14.4% | 12.3% |
1998 | 15.9% | 28.2% | 24.6% | 18.3% | 13.1% |
1999 | 18.8% | 25.3% | 22.8% | 20.3% | 12.8% |
2000 | 17.7% | 25.2% | 24.5% | 18.3% | 14.2% |
2001 | 21.4% | 22.6% | 24.6% | 16.9% | 14.5% |
2002 | 18.4% | 28.4% | 22.8% | 14.9% | 15.5% |
2003 | 18.0% | 30.0% | 22.8% | 14.5% | 14.7% |
2004 | 13.0% | 32.0% | 22.8% | 16.5% | 15.7% |
2005 | 16.8% | 27.7% | 24.3% | 15.1% | 16.1% |
2006 | 20.8% | 26.6% | 23.8% | 12.7% | 16.1% |
2007 | 18.5% | 28.0% | 28.4% | 10.6% | 14.5% |
2008 | 19.8% | 32.1% | 22.0% | 14.0% | 12.1% |
2009 | 18.0% | 35.2% | 20.3% | 14.3% | 12.2% |
2010 | 17.7% | 35.3% | 19.2% | 16.3% | 11.5% |
2011 | 17.4% | 34.1% | 23.1% | 12.4% | 13.1% |
2012 | 17.0% | 32.4% | 25.1% | 12.8% | 12.7% |
2013 | 16.9% | 32.3% | 27.6% | 10.7% | 12.5% |
2014 | 15.7% | 30.7% | 28.7% | 13.9% | 10.9% |
2015 | 15.6% | 33.1% | 25.0% | 15.2% | 11.1% |
2016 | 15.6% | 32.7% | 25.2% | 19.0% | 7.4% |
2017 | 15.9% | 29.0% | 28.5% | 17.6% | 9.0% |
2018 | 14.1% | 32.2% | 27.1% | 16.9% | 9.8% |
2019 | 12.2% | 32.0% | 28.0% | 17.0% | 10.7% |
AVERAGE | 17.5% | 30.4% | 24.5% | 15.2% | 12.5% |
The table is somewhat similar to the first one. Perhaps the most interesting part of the pitchers comes from the quality of pitching by age, as seen below.
Season | 24 and Under WAR/200 IP | 25-27 WAR/200 IP | 28-30 WAR/200 IP | 31-33 WAR/200 IP | 34+ WAR/200 IP |
---|---|---|---|---|---|
1980 | 2.1 | 1.7 | 1.8 | 1.8 | 2.6 |
1981 | 2.3 | 1.7 | 1.9 | 1.7 | 2.5 |
1982 | 2.2 | 1.8 | 1.8 | 1.8 | 2.6 |
1983 | 2.1 | 1.9 | 2.2 | 1.5 | 2.2 |
1984 | 2.3 | 1.9 | 2.0 | 1.6 | 2.1 |
1985 | 2.3 | 1.9 | 1.8 | 1.8 | 2.0 |
1986 | 2.1 | 2.0 | 1.9 | 2.0 | 1.9 |
1987 | 1.9 | 1.8 | 2.1 | 2.1 | 2.2 |
1988 | 2.0 | 2.2 | 1.7 | 1.9 | 2.1 |
1989 | 2.0 | 2.1 | 1.8 | 2.1 | 1.8 |
1990 | 2.0 | 2.3 | 1.6 | 1.9 | 2.1 |
1991 | 2.0 | 1.9 | 2.1 | 1.8 | 2.1 |
1992 | 2.0 | 2.1 | 2.0 | 1.8 | 2.0 |
1993 | 1.6 | 2.0 | 2.3 | 2.2 | 1.7 |
1994 | 1.6 | 2.0 | 2.2 | 2.6 | 1.1 |
1995 | 1.2 | 1.9 | 2.2 | 2.5 | 2.1 |
1996 | 1.5 | 1.6 | 2.2 | 2.6 | 2.3 |
1997 | 1.7 | 1.7 | 2.2 | 2.2 | 2.5 |
1998 | 1.6 | 1.8 | 2.0 | 2.3 | 2.4 |
1999 | 1.8 | 2.0 | 1.7 | 2.1 | 2.4 |
2000 | 1.8 | 1.8 | 2.1 | 1.9 | 2.6 |
2001 | 2.0 | 1.6 | 2.1 | 1.8 | 2.5 |
2002 | 1.8 | 1.9 | 1.9 | 1.9 | 2.5 |
2003 | 2.0 | 1.9 | 1.9 | 2.0 | 2.2 |
2004 | 1.9 | 2.0 | 2.1 | 1.8 | 2.1 |
2005 | 2.2 | 2.0 | 1.9 | 2.0 | 2.0 |
2006 | 1.9 | 2.1 | 1.9 | 1.6 | 2.2 |
2007 | 1.8 | 2.0 | 1.9 | 2.2 | 2.0 |
2008 | 2.3 | 1.9 | 2.1 | 2.2 | 1.3 |
2009 | 1.9 | 2.2 | 2.0 | 1.9 | 1.6 |
2010 | 2.3 | 2.1 | 1.8 | 1.9 | 1.6 |
2011 | 2.0 | 2.1 | 2.0 | 1.6 | 1.9 |
2012 | 2.1 | 2.0 | 1.9 | 2.0 | 2.1 |
2013 | 2.1 | 2.1 | 1.9 | 1.9 | 1.7 |
2014 | 2.0 | 2.1 | 2.3 | 1.3 | 1.5 |
2015 | 2.0 | 2.2 | 2.0 | 1.9 | 1.3 |
2016 | 2.2 | 2.0 | 2.1 | 1.8 | 1.3 |
2017 | 2.1 | 1.8 | 2.2 | 2.1 | 1.5 |
2018 | 2.1 | 1.8 | 2.2 | 2.0 | 1.9 |
2019 | 2.0 | 1.8 | 1.9 | 2.2 | 2.3 |
Average | 2.0 | 1.9 | 2.0 | 2.0 | 2.0 |
Over time, the quality of pitching is fairly consistent across all age groups and hasn’t changed too much. None of the data above is static. It isn’t necessarily cyclical, but changes in the game affect the ability of older players to compete at a high level and younger player readiness.
Craig Edwards can be found on twitter @craigjedwards.
The number of years of control that a team has over a player is ridiculous. Players need to get to free agency sooner or get paid more in the arbitration process/raised league minimum, otherwise we’ll get another strike.