Weighted Runs Above Average (wRAA) is a baseball metric that measures the number of runs a player contributes to their team above or below an average player, with adjustments for league and park factors.
The result is:
0
How many Weighted Runs Above Average (wRAA) does a player have given their 0.32, 600, 0.315, 1.25, 0.11, 0.95, and 0.12?
Formula Explanation:
The wRAA formula takes a player’s Weighted On-Base Average (wOBA), subtracts the league-average wOBA, divides by the wOBA scale to normalize the difference, and multiplies by the player’s Plate Appearances (PA) to find the total runs contributed above or below average.
Detailed Explanation:
wRAA is built on the foundation of wOBA, a metric developed to value hitter’s contributions more accurately than traditional statistics like batting average. The use of league average wOBA and the wOBAScale ensures that wRAA remains a relative measure, adjusting for the offensive environment of the league in a given season.
Importance:
Understanding wRAA is crucial for front offices and analysts as it provides a singular number representing a player’s offensive contribution, helping in comparing players across different eras and ballparks.
Historical Use:
wRAA has been used historically to evaluate players in a way that is independent of team context and factors more controllable by the player. Historically, it has been applied in award voting, salary arbitration, and free agency to quantify a player’s offensive value.
Historical Context:
The concept of measuring players against an “average” baseline started gaining traction in sabermetric circles in the late 20th century, with wRAA being a modern evolution of these ideas. It represents an advancement from simpler metrics like RBI and runs scored, which are heavily context-dependent and do not isolate individual performance.
Limitations:
wRAA does not account for base-running or defensive value and is also influenced by changes in the offensive environment over time, which can affect cross-era comparisons.
Example:
A player with a wOBA of 0.350, 600 PAs, a league average wOBA of 0.320, and a wOBAScale of 1.25, calculates wRAA as: ((0.350 - 0.320) / 1.25) * 600 = 14.4 wRAA.
Famous Examples:
Babe Ruth: Ruth’s 1920 season, where he hit 54 home runs, would have given him a wRAA far exceeding any of his peers, highlighting his exceptional offensive value.
Barry Bonds: In 2004, Bonds posted a wOBA of .537, leading to a wRAA of 125.1, one of the highest single-season wRAA ever recorded.
Frequently Asked Questions:
How does wRAA differ from RBI or runs scored?
wRAA isolates a player’s value from their teammates’ performance, whereas RBI and runs scored are dependent on opportunities created by the team.
Can wRAA be used for pitchers?
No, wRAA is strictly an offensive metric and does not apply to pitchers.
How often is wRAA updated?
wRAA can be updated daily as new game data becomes available and as league averages fluctuate throughout the season.
Does wRAA correlate to wins?
While not direct, a higher team wRAA usually indicates a more potent offense, which can contribute to more wins.
Is there a threshold for a "good" wRAA?
There is no universal threshold, but generally, a wRAA above 20 is considered excellent, between 0 to 20 is above average, and below 0 is below average.
Sources:
MLB
Major League Baseball explanation of Weighted Runs Above Average (wRAA)
