Jaffe WAR Score system (JAWS)

The JAWS (Jaffe WAR Score system) was developed by sabermetrician Jay Jaffe — first at Baseball Prospectus in 2004 — as a means to measure a player's Hall of Fame worthiness by comparing him to the players at his position who are already enshrined, using advanced metrics to account for the wide variations in offensive levels that have occurred throughout the game's history. The stated goal is to improve the Hall of Fame's standards, or at least to maintain them rather than erode them, by admitting players who are at least as good as the average Hall of Famer at the position, using a means via which longevity isn't the sole determinant of worthiness.

A player's JAWS is his career WAR averaged with his 7-year peak WAR (not necessarily consecutive years). For non-pitchers, all non-pitching WAR (offense, defense, baserunning) is included in determining the averages, but any pitching WAR they might have accrued is not; right fielders aren't penalized by the additional value Babe Ruth accumulated on the mound, for example. The current Hall of Famers are then grouped by position and a position average JAWS is computed. For the purposes of comparison, a player is classified at the position where he accrued the most value, which may be different from the position where he played the most games, particularly as players tend to shift to positions of less defensive responsibility as they age. Within that process, a first-cut infield vs. outfield determination is made as well.

For some positions, the averages are skewed due to a lack of enshrined players at that position, so overall HOF average position players are added to that position's average until the total count of actual and average players matches that of the most inducted position (RF, currently 24).

As of the 2018 ballot cycle for the BBWAA processes, the averages by position are:

Unweighted with Avg HOFers Weighted with AVG HOFers
Pos Players
Other Groups
CI (1B + 3B)3567.242.755.0
MI (2B + SS)4268.243.856.0
OF (LF,CF,RF)6470.043.056.5
CO (1B,3B,LF,RF)8068.342.455.4
Md (C,2B,SS,CF)7666.142.354.2
Updated November 27, 2018

For all that is included, JAWS can't incorporate everything that goes into a player's Hall of Fame case. It makes no attempt to account for postseason play, awards won, leagues led in important categories, and career milestones, accomplishments that are better handled via the Bill James Hall of Fame Standards and Hall of Fame Monitor metrics.

For more on what goes into WAR, see Baseball-Reference.com's Explanation of Wins Above Replacement.

Jay Jaffe
November 19, 2012