wRAA Definition
Weighted Runs Above Average is an offensive baseball statistic, abbreviated as wRAA. This statistic allows baseball fans to compare a player’s offensive contribution to that of an average hitter. wRAA draws heavily on wOBA for its calculation, so be sure to visit our page on that statistic as well.
The Concept of wRAA
To understand the value a player brings to the field, it is helpful to compare that player to an average major leaguer. Anyone performing at an above-average level is contributing positively to the team’s performance, while someone below that level is a negative force. However, it can be difficult to compare players against an ‘average’ Major Leaguer, because you first need to identify what that average is and then find a way to measure the difference between a player and that average. wRAA attempts to solve this problem and does so while wrapping it up in an easy to understand number.
Quite simply, positive numbers are above average, and negative numbers are below average. A hitter with a positive number in this category is performing better than his average peer, while a negative number is below average.
This is a counting statistic, meaning players accrue (or lose) wRAA as the season goes along. If you are using the stat to compare one player to another, be sure to consider playing time. A player who gets more plate appearances will have more of an opportunity to rack up wRAA.
Aside from being a useful statistic in its own right, wRAA plays a valuable role as a component of Wins Above Replacement, or WAR. wRAA is used as the offensive piece of that calculation, with a player being credited for 1 win for every 10 wRAA accumulated.
Why is wRAA Important?
The importance of wRAA is the simplicity that it brings to offensive evaluation. Much like its close relative wOBA, wRAA attempts to roll up the various ways an offensive player can be valuable into a single number.
In other words, instead of looking at several different stats like batting average, OPS, home runs, etc., you could just look at wRAA and get an instant representation of a hitters performance.
As an example, let’s attempt to assess the value of two players from the 2018 season, first without the help of wRAA:
- Joey Votto: .284 BA, .417 OBP, 12 HR, 67 RBI
- Xander Bogaerts: .288 BA, .360 OBP, 23 HR, 103 RBI
From just those numbers alone, it’s hard to know what to make of this comparison. The batting averages are nearly identical, Bogaerts hit 11 more home runs and drove in 36 more runs, but Votto was on base far more frequently. It’s hard to know what factors are more valuable, so let’s see what wRAA has to say.
- Joey Votto: 27.9 wRAA
- Xander Bogaerts: 27.5 wRAA
In the end, it’s a virtual tie. Both players offered excellent performances at the plate which were well-above league average. One offered more power, while the other delivered more patience, but the end result was nearly the same.
Thanks to the simplicity of wRAA, we can easily compare hitters who deliver their value to the game in slightly different ways.
How is wRAA Calculated?
The calculation for wRAA is as follows:
wRAA = ((wOBA – league wOBA) / wOBA scale) x PA
It’s a pretty simple formula, and one which only requires a few easy-to-obtain inputs.
- wOBA = Weighted On Base Average. This statistic can be located in a number of places, such as FanGraphs or Baseball Reference.
- League wOBA = The league-wide average wOBA for any given season, which will obviously change from year to year. League-average wOBA can be seen at FanGraphs.
- wOBA Scale = This is a number used to weight wOBA properly in each season. Each season’s number can be found on FanGraphs.
- PA = Total number of plate appearances on the season for the player in question
What is a Good wRAA?
To highlight what kind of wRAA represents a strong performance over the course of a full season, we have compiled a couple of charts below.
Top Ten wRAA Scores for 2018 MLB Season
| Player | wRAA |
| Mookie Betts | 67.2 |
| Mike Trout | 65.4 |
| J.D. Martinez | 59.7 |
| Christian Yelich | 57.0 |
| Alex Bregman | 46.5 |
| Jose Ramirez | 43.7 |
| Paul Goldschmidt | 42.4 |
| Nolan Arenado | 41.7 |
| Trevor Story | 37.0 |
| Freddie Freeman | 36.4 |
Top Ten Single-Season wRAA Scores, 1900 – 2018
| Player | Year | wRAA |
| Babe Ruth | 1921 | 127.9 |
| Babe Ruth | 1923 | 124.7 |
| Babe Ruth | 1920 | 121.1 |
| Barry Bonds | 2001 | 117.7 |
| Lou Gehrig | 1927 | 110.9 |
| Barry Bonds | 2002 | 110.0 |
| Babe Ruth | 1927 | 109.9 |
| Babe Ruth | 1924 | 109.2 |
| Ted Williams | 1941 | 108.8 |
| Barry Bonds | 2004 | 108.0 |
What are the Problems with wRAA?
There is not much in the way of criticism that can be found regarding wRAA. As a league-adjusted stat, it does a great job of fairly evaluating hitters and comparing them to their peers. If anything, you could argue that the simplified view of looking at a hitter’s performance as just a single number misses the subtle ways in which each player is different.
For instance, going back to our comparison of Votto and Boegaerts, if you only looked at wRAA you wouldn’t have seen how those players arrived at their total production levels. With that said, no statistic can provide everything there is to be known about a player, so this minor critique is easily dismissed.
In all, wRAA is a highly valuable stat and one which should be used regularly in the evaluation of offensive performance.