JAWS (Jaffe Wins Above Replacement Score) is a system created by Jay Jaffe that evaluates a player's worthiness for enshrinement in the National Baseball Hall of Fame by comparing him to the Hall of Famers at his position. The stated goal of JAWS is to maintain or improve the Hall of Fame's standards by electing players who are at least as good as the average Hall of Famer at those players' positions.
A player's JAWS is calculated by averaging his career WAR with the total WAR from his seven-year peak -- that is, his seven most valuable seasons (consecutive or non-consecutive). This formula allows great players who lack longevity to be judged more favorably than they would by traditional methods.
For non-pitchers, any WAR accumulated at the plate, in the field and on the bases is included, while WAR amassed on the mound is not. This way, typical one-way players are not penalized when compared with the rare Hall of Famers who generated great value as a pitcher and as a hitter, such as Babe Ruth.
Grouping current Hall of Famers by position (using the fielding spot at which a player generated the most WAR in his career) allows for the creation of an average JAWS at each position. These averages serve as the basis for comparisons between non-Hall of Famers and those already enshrined.
To prevent the position-specific JAWS averages from being skewed by small sample sizes (fewer than 300 players are in the Hall altogether, with several positions represented by fewer than 20 players), "Hall of Fame average position players" are added to the formula until the total number of players in a positional group matches that of the most-inducted position (currently right field). These players are given JAWS equal to the average among all non-pitchers in the Hall of Fame.
For example, the Hall of Fame had just 13 third basemen prior to Chipper Jones' election in 2018, compared to 24 right fielders. Accordingly, the positional group used to generate the average JAWS (55.2) among Hall of Fame third basemen included those 13 hot-corner men and 11 "Hall of Fame average position players." Jones himself amassed 85 WAR in his career and 46.6 during his seven most productive seasons, based on WAR. Thus, his JAWS is 65.8.