JAWS and the 2015 Hall of Fame ballot: Introduction to JAWS

Explaining JAWS, Jay Jaffe's Hall of Fame evaluation system, and the breakdown of the Cooperstown standards at each position.

With the announcement of the BBWAA Hall of Fame ballot comes the launch of my 12th annual JAWS ballot breakdown series. As I’ve done since introducing my system at Baseball Prospectus for the 2004 ballot, I’ll examine each candidate’s career in light of both the popular perception of his candidacy as well as a sabermetric reckoning. Rather than crowding each evaluation with a description of my system, I’ll use this space to lay out the nuts and bolts and then link to it within each breakdown.

JAWS and the 2015 Hall of Fame ballot: Burning questions

​For the uninitiated, JAWS is short for Jaffe Wins Above Replacement Score. Like the famous cinematic shark, the catchy, self-referential acronym (introduced a year after the system’s debut) generally elicits screams at the first hint of its approach, because not everybody can withstand this deep dive into the debate over who is worthy of Cooperstown. But if you’re somebody who does like to partake in the discussion and chew on the candidacies, JAWS is for you. 

JAWS is a tool for measuring a candidate’s Hall of Fame worthiness by comparing him to the players at his position who are already enshrined. It uses the Baseball-Reference.com version of Wins Above Replacement to estimate a player's total hitting, pitching and defensive value to account for the wide variations in scoring levels that have occurred throughout the game's history and from ballpark to ballpark. A player's JAWS is the average of his career WAR total and that of his peak, which I define as his best seven years. All three are useful to compare to the average Hall of Famer at the candidate’s position.

For the purposes of that comparison, players are classified at the position where they accrued the most value, which may be different from where they played the most games, particularly as players tend to shift to positions of less defensive responsibility — and thus less overall value — as they age. A small handful of enshrined players, including pioneers and Negro Leaguers with less than 10 years of major league service, are excluded from the calculations; Satchel Paige and Monte Irvin, for example, had major league careers too short to use as yardsticks for non-Negro League players.

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​The system's stated goal is to improve the institution's standards, or at least to maintain them by identifying and (hopefully) admitting players at least as good as the average Hall of Famer at the position. More than anything, the idea is to bring a measure of intellectual consistency to an often disorganized debate. Because of that, JAWS has gained a nice bit of exposure in recent years, cited by actual Hall of Fame voters, included within MLB Network'stelevision coverage, and its slated to fill the pages of a forthcoming book by yours truly.

When I began this series, I used BP's version of Wins Above Replacement Player. For the 2013 ballot, I switched to Baseball-Reference.com's version of WAR, and site owner Sean Forman aided the process by creating several handy tools, including JAWS data on each player page and sortable positional leaderboards. B-Ref also has other useful tools for any Hall of Fame discussion, including past voting results and projected future ballots.

For all that it includes, JAWS can't incorporate everything that goes into a player’s Hall of Fame case. The system makes no attempt to account for postseason play, awards won, leading the league in important categories, career milestones and historical importance, most of which is better handled via the Bill James Hall of Fame Standards and Hall of Fame Monitor metrics. That information is all germane to the Cooperstown discussion, and can shade an argument for or against a player whose credentials are otherwise borderline, so I’ll incorporate it into my write-ups.

My system owes a great deal of inspiration to James' Historical Abstracts, both the 1985 original, which planted the career/peak distinction in my mind, and the 2001 version, which weighted a player's best seasons (using Win Shares) to produce a somewhat more transparent means of combining career and peak into a single ranking. In JAWS, a player's best seasons are effectively double-counted, an appropriate strategy given research into pennants added and the premium value of star talent, in that individual greatness can have a non-linear effect on team results, both in the standings and on the bottom line.

Here are the current positional standards:

Position	number	career war	peak war	jaws
SP	59	73.4	50.2	61.8
RP	5	40.6	28.2	34.4
C	13	52.5	33.8	43.1
1B	19	65.9	42.4	54.2
2B	19	69.4	44.5	57.0
3B	13	67.4	42.7	55.0
SS	21	66.7	42.8	54.7
LF	19	65.1	41.5	53.3
CF	18	70.4	44.1	57.2
RF	24	73.2	42.9	58.1
CI (1B + 3B)	32	66.0	42.4	54.2
MI (2B + SS)	40	68.1	43.8	55.9
OF (LF, CF, RF)	61	69.9	42.8	56.3
CO (1B, 3B, LF, RF)	75	67.9	42.2	55.1
Md (C, 2B, SS, CF)	71	65.7	42.0	53.9

As with the past two election cycles I’ve covered for SI.com, I will devote individual articles to the top candidates, updating my previous work to ensure that it reflects their most recent ballot results as well as any changes to WAR. I'll also devote shorter write-ups to lesser candidates with no shot at election, and batch several of those together. While it's true that I could just as easily skip the likes of Darin Erstad and Cliff Floyd, I've always felt that a player's appearance on the ballot itself is worth at least a brief valedictory, and I'm not about to break my Cal Ripken-like streak of covering every candidate.

In my next post, I’ll begin examining the newcomers whose stays on the ballot will be short, and we'll soon announce the full schedule of JAWS posts that will take us from this week through the Dec. 27 deadline for ballots to be submitted.