WAR Basics
WAR is
the approximate value of wins that a player added (or subtracted) to his team.
Finding a certain player’s value is often very difficult and somewhat
subjective. What I value in a player could be different from what you value in
a player, and that value doesn’t necessarily have to be in the form of wins.
You could call your statistic Value Added and the gist of it would still be the
same: Which player was more valuable?
WAR is a
blueprint. It doesn’t tell you what statistics you have to use or value. Many
of the popular WAR methods follow the same blueprint: an offensive
component(s), a defensive component, and a positional adjustment displayed as
values above or below a league average. This gives you the value of the given
player as compared to a league average. Baseball Reference calls this WAA (wins
above average) and so will I. After this, you add in a replacement adjustment
for each league and boom, there you have it, WAR. WAR offers a lot of leeway inherently.
Offense + Defense + Position + Replacement = WAR. It doesn’t tell you what you
have to quantify any of these numbers with. If you think that batting average
is the holy grail of offensive statistics, all you have to do is convert a
given players batting average to runs and you have your offensive component.
There is nothing inherent about WAR’s framework that tells you that you cannot
do this.
If you
are trying to find a theme so far, WAR is wide open to different
interpretations.
RE24 Basics
RE24, or
Run Expectancy based on the 24 base/out states, is the difference in run
expectancy between the start of a play and at the end of a play. It is a
descriptive statistic as opposed to a predictive statistic. A story-telling
statistic is what some people call these types of numbers. It tells what happened.
Say, for instance, Justin Upton walks to the plate with Andrelton Simmons
standing on first base and no outs. The run expectancy of this plate appearance
is 0.941 runs which simply means that, on average, 0.941 runs are scored are
scored either in this plate appearance or through the end of the inning. If
Justin hits a single and Andrelton stops at second base, the run expectancy is
now 1.556 runs. To get Justin Upton’s added run expectancy, you take the run
expectancy at the end of the play and you subtract the run expectancy from the
beginning of the play. End of play = 1.556, beginning of play = 0.941 so 1.556
– 0.941 = 0.615. Justin Upton’s RE24 for this plate appearance is 0.615 runs.
Do this for every play of the season and you have a player’s annual RE24.
(Justin Upton’s was 22.2 for the 2013 season which placed him 28th in the NL among batters in case you were wondering).
RE24 is
very good at telling you how much offensive value a player added or subtracted
on a given play in terms of runs. Everyone can agree that having both first and
second base occupied will lead to more runs than just first base occupied no
matter what else happened barring any outs. RE24 does not care about the how.
All it cares about is the input and output of a play. It combines the ability
to create runs by yourself and the ability to create runs contextually. A
double with a man on third base is more valuable than a double with no men on,
but also, it is worse to not advance the man on third to score a run than it is
to groundout with nobody on. It gives the batter its due reward for hitting
well in context but also penalizes accordingly.
Using RE24 as the Offensive Component to WAR
RE24 is
a great story-telling statistic that tells you how a player faired in the
situations he was provided, and it also comes in a very easy-to-use package. It
is already stated as runs above or below the league average. RE24 is great for
my interpretation of WAR. Rather than trying to deduce the intrinsic value of a
player in a vacuum, I want to see how that player contributed to his teams
wins. I see WAR as a story-telling statistic. I do not need WAR to be
predictive of what will happen the next year. When I want to compare how two
different players played in a season, I do not need the statistic to try to be
something no one statistic can be: a perfect representation of a player’s
current skill. All I need to see is how he contributed to his team’s
performance between two endpoints. All I need to know about Matt Carpenter’s
2013 season is what he contributed to the Cardinals’ overall performance. When
evaluating Matt Carpenter’s 2013 season, I do not need to know how he should
have performed or how he will perform in the future. My value in terms of
seasonal WAR is purely descriptive. Matt Carpenter added 52.4 runs offensively
(according to RE24). This does not mean he will add 52.4 runs offensively in
2014. It doesn’t even mean he will add 1 run offensively in 2014, but I don’t
need WAR to be predictive. It is a story-telling statistic that approximates a
certain player’s contributions to his team in terms of on-field production.
Introducing nWAR
nWAR is my
WAR formula which uses the basic, most popular framework. Offense + Defense +
Position + Replacement = WAR. For the offensive production I use RE24 with an
additive park adjustment based on home field and the Ultimate Base Running
statistic from Fangraphs (because it does not include stolen base attempts for
which RE24 already accounts for), for the defensive component I use an average
of the Ultimate Zone Rating and the Defensive Runs Saved metrics, and I use the
methods outlined in Tom Tango’s “How to calculate WAR” for my position values
as well as the replacement values for each league.
To give
you an example we’ll use Justin Upton again. Let’s start with his RE24, which
is what I said before, 22.2. Adjust this for the slight hitter’s lean of Turner
Field and we have an aRE24 (RE24 adjusted for the hitter’s home park) of 19.5.
Add in his baserunning score of 5 runs above average and we have an offensive
runs above average of 24.5. Next, take the average of his UZR (Ultimate Zone
Rating) and DRS (Defensive Runs Saved) ratings. I do this because both systems
are good on their own, but they both have shortfalls. Taking the average seems
to balance out these shortfalls. It is not perfect, but it is very good and it
is the best quantifiable defensive metrics we have available. Upton’s UZR was –9.6
and his DRS was –5. Not a very good year for Justin defensively with –7.3
defensive runs above average. To convert these run values to wins you simply
divide them by 10.5 using Tango’s method. Justin has a combined 17.2 runs above
average so far (19.5 + 5 + [–7.3]) = 17.2. So his wins above average so far is roughly
1.64 wins (that’s a rounded figure). Up next comes the position adjustment.
Justin played 147 games as a corner outfielder and 2 as a designated hitter.
Using Tom Tango’s positional adjustments we get –0.5 wins. Next we have the
replacement adjustment and for the National League it is 2 wins for every 162
games. Justin played 149 games so his replacement adjustment is 1.8 wins. To
put all of that together we just find the sum. (1.64 + [–0.5] + 1.8) = 3.0 wins
above average (there is some rounding in there because I thought it would look
better to just keep it to one decimal point for the readability). And there we
have it. Justin Upton’s 2013 nWAR is 3.0.
For
pitchers I use their RE24 value and adjust it for their home park. Then, I
convert his aRE24 to an expected runs allowed by dividing it by the number of
innings pitched and multiplying it by nine. This number gives us the pitcher’s
runs above average per nine innings. To get this number into runs allowed per nine
innings we subtract it from the average runs allowed per nine innings for each
league (4 in the NL and 4.33 in the AL).
If you
did not follow that, I’ll give you an example.
Cliff
Lee pitched 222.2 innings in 2013 and had an RE24 of 24.6. A simple additive
park factor adjustment of about 0.449 runs per inning gives us an aRE24 of
26.6. We then take this number and break it down to runs above average (above
average meaning better statistically not literally more than average) per nine
innings. So we have (aRE24 ∕ Inn) x 9 = (26.6 ∕ 222.67 [two-thirds of an inning]) x 9 = 1.07 runs above average per nine innings.
We then subtract the average runs allowed per nine innings from the runs above
average per nine innings. 4 – 1.07 = 2.93. Cliff Lee’s expected runs allowed
per nine innings based off of aRE24 is 2.93 runs. We’ll call this number xRA. We
then use xRA and follow Tango’s method for calculating WAR for pitchers. We create
his run environment then calculate his winning percentage based off of his xRA
and average run environment. Add in a similar replacement adjustment that we
used for the batters and we have our nWAR for pitchers.
Here is
a list of some of the Top 10 position players from each league according to
nWAR:
NL
|
|
AL
|
|
Player
|
nWAR
|
Player
|
nWAR
|
Paul Goldschmidt
|
8.2
|
Mike Trout
|
10.3
|
Andrew McCutchen
|
7.7
|
Josh Donaldson
|
8.1
|
Matt Carpenter
|
7.4
|
Chris Davis
|
7.5
|
Carlos Gomez
|
7.4
|
Robinson Cano
|
7.1
|
Freddie Freeman
|
7.0
|
Miguel Cabrera
|
7.0
|
Yadier Molina
|
6.4
|
Shane Victorino
|
6.0
|
Hunter Pence
|
5.9
|
Evan Longoria
|
5.9
|
Joey Votto
|
5.9
|
Jason Kipnis
|
5.7
|
Matt Holliday
|
5.4
|
Manny Machado
|
5.6
|
Shin-Soo Choo
|
5.3
|
Carlos Santana
|
5.1
|
And here
are the Top 5 pitchers from each league:
NL
|
|
AL
|
|
Player
|
nWAR
|
Player
|
nWAR
|
Clayton Kershaw
|
8.1
|
Yu Darvish
|
7.6
|
Jose Fernandez
|
6.6
|
Max Scherzer
|
7.5
|
Cliff Lee
|
6.0
|
James Shields
|
7.2
|
Jhouylis Chacin
|
5.9
|
Chris Sale
|
7.1
|
Adam Wainwright
|
5.6
|
Anibal Sanchez
|
6.8
|
Okay,
well, there you have it. This is my take on WAR including the why and the how I
did it. Remember that WAR is simply a framework from which to start. I think
this version of WAR accurately displays what I want it to tell me. Who added
the most value to his respective team on the field?