This week we’ll be looking at an offensive statistic that is helpful in evaluating a batter’s contribution to his team, Weighted Runs Above Average (wRAA).  So far, the most important offensive statistics that we have looked at in my opinion have been Weighted Runs Created (wRC), On-Base Plus Slugging Plus (OPS+) and Weighted On-Base Average (wOBA).

wRAA is a counting statistic that heavily uses wOBA for its analysis and helps show us, according to FanGraphs, the amount of “offensive runs a player contributes to their team compared to the average player” over the course of a season.

If a player has a wRAA of zero, then he is league average and anything above that is a positive contribution to the team’s runs and anything below is a negative contribution.

All you need to calculate wRAA is a player’s wOBA, the league wOBA, the wOBA scale coefficient for that season and the amount of Plate Appearances made by that player that season.  Luckily, FanGraphs provides the first three factors for us, making out calculations much simpler.

The formula for wRAA is:

wRAA = ((wOBA - league wOBA) / wOBA scale) × PA

Additionally, the chart for how to evaluate a player based on his wRAA is as follows:

One last interesting fact about wRAA is that when calculating Wins Above Replacement (WAR), wRAA is used to show a player’s offensive ability when their entire body of work is taken into account and a wRAA of 10 is equal to 1 WAR or one win above replacement level players.