First, an introduction: I’m Adam Darowski and I’m a longtime fan (and occasional commenter) of HHS and its previous incarnations. If you’ve seen my name before, it was likely related to the Hall of wWAR work that I’ve done. I also contribute to Beyond the Box Score and Baseball Past and Present. This is my first post at HighHeatStats, though I already have another project in the works. Hi, everyone!
When Baseball-Reference updated their Wins Above Replacement (WAR) framework, they included Wins Above Average (WAA). Personally, I found this to be a tremendous addition. I had recently started calculating and visualizing Wins Above Average based on Rally’s original WAR spreadsheets. While B-R rendered all of my underlying data useless, they at least had the decency to save me from redoing all my work.
As I’ve started using WAA, I’ve had people ask me:
- What’s the difference between WAR and WAA? and
- Why haven’t we just been using WAA all along?
While both metrics are similar, they do serve very different purposes.
Perhaps the most difficult sabermetric concept to explain to uninitiated baseball fans (not even “casual”—just not objectively-focused) is that of the replacement player. Why in the world, they ask, would I compare a star to some AAA scrub?
Wins Above Replacement is useful for measuring the value of a player over the player freely available to replace him with. For the most part, every average player in baseball is employed by a big league club already. If you need to fill a hole on your roster, you either need to:
- Sign an expensive free agent (costs you monetary assets)
- Trade for a player (costs you other player assets) or
- Pick up a freely available player.
#3 is your replacement player. He’s the guy you can get for (essentially) nothing.
A good example of a replacement player is Mauro Gomez. Mauro Gomez is hitting over .300 and slugging over .600 for AAA Pawtucket so far this year. When Will Middlebrooks was conveniently hurt (immediately following the Kevin Youkilis trade), Gomez was recalled. The Red Sox didn’t trade for anyone—they grabbed a replacement player (not a prospect—someone that they pretty much got for free over the offseason). Gomez showed a bit power, hitting .300 with three doubles in nine games. But he also exposed why he’s a replacement player—his glove. DRS already rates his defense as four runs below average (in just nine games!). His Baseball-Reference WAR sits at –0.4. He’s a replacement player.
When WAA is Better
I do a lot of research related to the Hall of Fame. In my work, I’m not building rosters, I’m trying to figure out who the greatest players of all time were. For this reason, WAA might be a better metric for me to use than WAR. When considering someone for the Hall of Fame, do you say “Wow, he was so much better than the AAA players of his day?” or “Wow, he was so much better than everyone else?” I find WAA is a better way to measure how much a player was better than “everyone else”.
Why? WAR rewards you for just being there. WAA does not.
62% of WAR is Just Showing Up
For Pete Rose, it was.
Pete Rose was worth 76.7 WAR for his career. But he was also worth just 29.2 WAA. That’s a huge difference. Take Charlie Keller. He’s on the opposite end of the spectrum. Keller was worth 40.6 WAR, but 29.0 WAA. Yes, King Kong Keller’s WAA was about the same as Pete Rose’s.
What’s happening here? Rose played forever (15,890 PA). Keller didn’t (4,604 PA). WAR rewards you for playing time, as long as you’re better than a AAA player. WAA, meanwhile, will rip you apart if you’re below average.
Through age 35, Pete Rose was worth (in 10,001 PA), 70.1 WAR and 39.8 WAA. He had 2,762 hits at that point. You can see what I’m getting at here. From that point on, Rose collected 5,889 more PAs. He added a bit to his career WAR (just 6.6 WAR in ten years). However, he destroyed his WAA, coming in at –10.7.
At the same time, he collected his 3,000th hit, his 4,000th hit, and—most importantly—his 4,192nd (though the 4,190th turned out to really be the important one). So, while he was dismantling his WAA, he was building his legacy.
Therein lies the dilemma—showing up is still important, but the importance differs depending on the context). WAR rewards the ability to show up, WAA does not.
The Actual Difference Between the Two
The components of WAR are expressed in runs above or below average, not replacement. To calculate WAR, you need to make a replacement adjustment that is based on playing time. WAA simply eliminates that adjustment.
Here are Rose’s WAR components:
- +368 runs for batting
- +13 runs for baserunning
- +5 runs for avoiding double plays
- –54 runs for his defense
- –91 runs for the positions he played
That’s a total of +241 runs above average. If you convert those runs to wins, you get 29.2 WAA.
If you add one more component, though:
- +492 replacement runs, based on playing time
Rose then has a total of +733 runs above replacement. That converts to 76.7 WAR. Those 492 runs say “if a replacement player played as much as Rose, he would have been worth 492 runs below average“. Therefore, Rose is 241 runs above average, but a whopping 733 above replacement—mostly because of how long he played.