HHS contributor Michael Hoban has written a comprehensive paper on assessing career value for players of the past century (since 1920), commonly known as the live ball era. This series presents a condensed version of Michael’s work for your assessment and discussion.

Fans of any sport are usually interested in knowing who are (or were) the best players in the game. Baseball fans are particularly fortunate in that no other sport rivals baseball for the sheer number of statistics available for comparing the players. In fact, there are so many numbers available that it often leads to confusion as to what to look at in order to judge how good a player really is (or was).

For many years, a player’s batting average (BA) was used to suggest who were the best hitters.  But, careful analysis over a number of years has now convinced us that a combination of on-base-percentage (OBP) and slugging average (SLG) is a better indicator of who were the most effective batters. 

Of course, in baseball, batting alone does not tell us who is a “better player.”  Fielding must also enter into the equation.  And judging fielding has always been more difficult than judging hitting.  The skills required of a good shortstop or catcher are much different than those required of a left fielder or a first baseman.  And attempting to judge who was the best “all-around” player has always been difficult.

But not to worry.  Over the years, there have been a number of dedicated people who have devoted a considerable amount of time into researching these questions.  And I am happy to report that (in my view) the most highly respected of all of these analysts, Bill James, has developed a system that I believe is a quantum leap ahead of all such systems in this regard.

Win Shares

In 2002, Bill James published his book titled WIN SHARES, introducing a system of the same name for evaluating and comparing player performance. The key to the value of Win Shares is that it tells us how valuable a player was to his team each season.  And, of course, a player’s value to his team is what the game is really all about.

Win Shares is a very complex system (the book is 728 pages long).  First, like any valid evaluation system, it measures a player’s value relative to the era in which he played and to the playing conditions under which he performed.  But the second (and more remarkable achievement) is that it appears to be able to measure a player’s value regardless of whether he played on a winning or a losing team.  Thankfully, it is not necessary to completely understand how the Win Shares system works in order to appreciate the results that it produces.

Put as simply as possible, here is what the Win Shares system does – it tells us how good a season a player had.  It awards a team a certain number of win shares for the season – depending on the number of games that the team won during the season.  It then takes those win shares and distributes them among the players on the team depending on each player’s contribution to the team during the season.  And, as a rule of thumb, here is how the number of win shares in a season can be interpreted for an individual position player:

30-40 win shares  =  MVP-type Season
20-30 win shares = All-Star Season
10-20 win shares = solid regular player
0-10 win shares = bench player

As an example of win shares results, here are the best seasons by some of the greatest players in baseball history:

Honus Wagner…..1908…..59 win shares
Babe Ruth………….1923…..55
Walter Johnson….1913…..54
Barry Bonds……….2001…..54
Mickey Mantle……1957…..51
Ted Williams………1946…..49
Ty Cobb……………..1915…..48
Stan Musial………..1948…..46
Cy Young……………1892…..44
Willie Mays…………1965…..43
Hank Aaron………..1963…..41

Career Value

The Win Shares system does a wonderful job of telling us how good a season a player had. But how do you go from the examination of a player’s individual seasons to a conclusion about his career?  This is the essential question that I wish to answer.  And, of course, a simplistic answer might be: just add up the win shares from all his seasons and that will tell you.  That is, if you know the total of a player’s career win shares, you can judge how good he was.  But, I think it is not quite as easy as that.

Unfortunately, the evaluation of many players’ careers is more complicated than just adding up the Win Shares of each season of a career. For example, Hall of Famer Dave Winfield had 415 career win shares while fellow Hall of Famer Joe DiMaggio had 387.  Does that mean that Winfield had a better career than DiMaggio or that Dave belongs in the Hall of Fame but Joe does not?  Of course not. Or, consider Hall of Fame pitcher Don Sutton, who had 319 career win shares, and fellow Hall of Famer Juan Marichal who had 263.  Does that mean that Sutton was a better pitcher than Marichal?  I think that very few fans would reach that conclusion.

CAWS

The point here is that total career win shares alone does not tell us enough about a player’s career.  And that is where CAWS (Career Assessment Win Shares) adds to the value of the Win Shares system.  CAWS suggests that a better (and fairer) way to judge a player’s career is to combine the win shares from a player’s ten best seasons plus an appropriate amount of credit for the player’s longevity.

Here is the CAWS formula:     CAWS  = CV  +  .25(CWS – CV) where

CAWS  =  Career Assessment Win Shares
CV  =  Core Value  =  sum of win shares for a player’s ten best seasons
CWS  =  total career win shares
.25(CWS – CV)  =  longevity factor  =  credit earned for a longer career

It is my contention that it is helpful to examine a player’s ten best seasons (what I am calling his “core value”) in order to get a better idea of how good he really is (or was).  But, at the same time, one must give some appropriate credit to a player’s career achievements.  It is this balancing of career accomplishments and core value that will tell us who had the best careers of all time.

Core Value

To demonstrate the use of Core Value, consider a player like Al Kaline, who played for twenty-two years and compiled 443 career win shares, compared to a player like Joe DiMaggio with 387 career win shares, but from a career of only thirteen seasons. During his ten best seasons, Joe DiMaggio accumulated 325 win shares – meaning that he averaged 32.5 win shares per season for those ten seasons – a spectacular achievement given, as we saw above, that MVP type seasons are those with 30 or more win shares. Al Kaline earned 268 win shares over his ten best seasons, impressive All-Star level performance, but nowhere near DiMaggio’s accomplishment.  And so we can begin to see that Joe D was a substantially better player.   

The Hall of Fame requires that a player must have at least ten years of major league service to be considered for induction into the Hall.  And, if we are going to speak of a player’s “core value” for the purpose of evaluating his career, then it seems appropriate to use this “ten year” measure – since, indeed, we wish to recognize the “best.”  That is, I will define a player’s core value (CV) as the sum of the win shares that he earned during his ten best seasons.

Note that core value is not the same as “peak value”, which other evaluation systems define as a player’s best three, five or seven seasons. The fact that peak value is judged by different benchmarks demonstrates what is fairly intuitive: that different players will have different numbers of peak years.  But I am suggesting that, regardless of how many peak years a player may have had, the player’s ten best seasons may be considered the core of his career. 

Note that Core Value already includes at least 55% of a player’s career win shares for all of the great position players – even those with the longest careers.  For example, Hank Aaron played for twenty-three seasons and accumulated 643 career win shares.  During his ten best seasons, he earned 356 win shares.  This represents 55% of his total win shares, one of the lowest CV percentages for any of the truly great position players. 

Longevity Factor

So, how should we value the remainder of a player’s career, for those seasons outside of his best 10? That is where the longevity factor is employed to credit a player with an additional 25% of the career win shares not already included in his Core Value. This factor, smaller for shorter careers and larger for longer ones, acknowledges the value of longevity without allowing the quantity of a career to overwhelm its quality.

Why did I choose 25%? In examining the numbers, I made the decision that the CAWS should represent at least two-thirds of a player’s career win shares; the 25% evolved from this decision. That is, every player’s CAWS score represents at least 67% of his career win shares.  For most players, it represents a much higher percentage than that. I did experiment with using other percentages such as 15%, 33% and 50%.   For example, if we use 33% in the formula instead of 25%, a few relatively small changes would take place – obviously benefiting those players like Hank Aaron and Pete Rose who had particularly long careers.  But, after much deliberation, I finally decided that 25% of the non-core win shares seemed to address the value of a player’s longevity in the fairest manner; but, it was strictly a judgment call.

In Part 2, I will look at CAWS and Hall of Fame standards, and present CAWS scores for the best players of the past century. If you would like to calculate CAWS for players of interest to you, Bill James is now providing, for free, season by season Win Shares totals for any player. I’ll let you do the math to calculate the corresponding CAWS scores.