Most of you are at least somewhat familiar with WAR and how it works. I’d bet most of you are familiar that Fangraphs publishes their own WAR (fWAR) and Baseball Reference publishes their own. BRef’s WAR is based on Rally Monkey’s formula and it’s been referred to as rWAR for a few years now. There are some key differences between the way these are calculated.
First of all, they use a different defensive metric. Fangraphs uses UZR while the one published on Baseball Reference uses Rally’s defensive metric called Total Zone. More importantly than that though, the two systems use a different baseline for replacement level. fWAR uses around a .280 winning percentage while rWAR is at about .320. As a result, there are many more wins available using the method Fangraphs does. About 6 per team or so. Furthermore, fWAR uses wOBA while rWAR uses BaseRuns. Only stolen bases and times caught stealing are considered for fWAR (it’s part of the wOBA calculation). rWAR calculates baserunning runs. fWAR doesn’t consider GIDP. rWAR does.
fWAR was a great way to look at a player’s value prior to Baseball Reference publishing them, but rWAR is the superior figure because it incorporates so much more. BaseRuns is significantly better than using wOBA to calculate runs.
For pitchers, fWAR considers only what a pitcher has complete control over. The stats used to calculate defense indpenent pitching stats like FIP (walks, strikeouts, HBP, home runs). rWAR considers the runs allowed and then takes the team defensive rating and assigns a value for the defensive contribution based on playing time. If 100 innings have been pitched by a team and their defense is 10 runs, then rWAR spreads those 10 runs around. A pitcher who threw 10 innings was helped by 1 run by his defense.
WAR is simply a framework for calculating how valuable a player is. You don’t have to use UZR or Total Zone. You can substitute any defensive metric you want. I’ve seen some use the Fans Scouting Report. There is Dewan’s Defensive Runs Saved (DRS), a run value on defense could be calculated using THT’s old defensive stats (RZR and OOZ). You can use different metrics for offense as long as you’re converting that metric into runs. So whatever metric you choose has to be able to covert to runs. You can use a stat like FIP which considers only strikeouts, walks, and home runs. You could use tRA which considers that information and batted ball types. You could use RA as long as you adjust for defense.
As a result, you’re going to get different WAR figures. That’s why rWAR and fWAR differ as much as they do. On here we often reference fWAR, but ignore rWAR altogether even though I think it’s the superior metric. I wanted to publish the fWAR and rWAR for the Cubs players and talk about which players the systems most disagree on.
| Name | PA | rWAR | fWAR | Diff-WAR |
| Starlin Castro | 141 | 0.0 | 0.5 | 0.5 |
| Geovany Soto | 117 | 0.6 | 0.9 | 0.3 |
| Jeff Baker | 62 | 0.2 | 0.5 | 0.3 |
| Carlos Pena | 101 | -0.3 | -0.1 | 0.2 |
| Reed Johnson | 35 | 0.1 | 0.3 | 0.2 |
| Blake DeWitt | 26 | 0.1 | 0.2 | 0.1 |
| Koyie Hill | 15 | 0.0 | 0.1 | 0.1 |
| Marlon Byrd | 135 | 0.1 | 0.2 | 0.1 |
| Darwin Barney | 120 | 0.5 | 0.6 | 0.1 |
| Tyler Colvin | 64 | -0.7 | -0.6 | 0.1 |
| Alfonso Soriano | 117 | 0.5 | 0.4 | -0.1 |
| Aramis Ramirez | 130 | 0.4 | 0.2 | -0.2 |
| Kosuke Fukudome | 92 | 1.5 | 1 | -0.5 |
rWAR hasn’t been the least bit impressed with Starlin Castro since he came into the league. In fact, his career rWAR (647 PA) is only 0.4. That’s a full season as yesterday marked the one year anniversary of his call-up and he’s been an everyday player since he came to Chicago. rWAR sees Castro as slightly better than replacement and exactly replacement level this season. The difference with Soto is likely just the baseline being used. rWAR sees Fukudome as being worth 1.5 wins already, but Fangraphs has him worth only 1. rWAR sees Barney as being the 3rd most valuable position player on the Cubs. Fukudome ranks 6th in the NL in rWAR and has many fewer plate appearances than the 5 ahead of him.
| Name | IP | rWAR | fWAR | Diff |
| Matt Garza | 44.2 | 0.3 | 2 | 1.7 |
| Ryan Dempster | 38 | -1.2 | -0.2 | 1 |
| James Russell | 18.1 | -0.7 | -0.3 | 0.4 |
| Carlos Zambrano | 44.2 | 0.5 | 0.8 | 0.3 |
| Marcos Mateo | 13.2 | -0.1 | 0.2 | 0.3 |
| Casey Coleman | 24.1 | -0.1 | 0 | 0.1 |
| John Grabow | 13 | -0.1 | -0.1 | 0 |
| Sean Marshall | 14 | 0.7 | 0.7 | 0 |
| Jeff Stevens | 7 | 0 | -0.1 | -0.1 |
| Carlos Marmol | 14.2 | 0.7 | 0.5 | -0.2 |
| Andrew Cashner | 5.1 | 0.2 | 0 | -0.2 |
| Justin Berg | 8 | 0.1 | -0.1 | -0.2 |
| Randy Wells | 6 | 0.3 | 0 | -0.3 |
| Jeff Samardzija | 18.1 | 0.5 | 0.1 | -0.4 |
| Kerry Wood | 13 | 0.7 | 0.2 | -0.5 |
No surprise to see Matt Garza as the biggest loser when we compare him to his rWAR. His FIP has been ridiculously good so far, which results in an impressive fWAR. His RA total hasn’t been nearly as impressive. Among starting pitchers, we see that Carlos Zambrano has been the most valuable starter according to rWAR. James Russell goes from bad in fWAR to horrible. Same thing for Dempster. Sean Marshall, Carlos Marmol and Kerry Wood are tied for the team lead in rWAR among pitchers. Impressive bullpen, but not so impressive rotation. The rotation as a whole has been worth .5 rWAR compared to 2.3 fWAR. Sean Marshall’s 6 Runs Above Replacement (RAR) on Baseball Reference leads all Cubs pitchers.
Among all players on the Cubs this season, Garza loses the most when we compares his fWAR to his rWAR. Dempster is next and Castro is right after him. If you look at fWAR you might think Garza is going to win the Cy Young Award and that Castro is a really good shortstop for his age. If you look at rWAR, you see that Garza has been just OK and Castro has been a replacement level shortstop so far.
I’m not saying one is right. I don’t think that either one of them is right. They use slightly different methods to get the totals that they do. I think defensive totals at this point in the season are a joke and wouldn’t include them if it were me. A team defense adjustment I can get behind for pitchers, but not for individual players. So I’d exclude UZR, Total Zone or any defensive metric at this point. That’s just me though.