Win Shares

Rating:
Summary: interesting but flawed
Review: The concept of win shares is wonderful and represents a fascinating step forward in sabermetric analysis. Any book that provides a single number to measure the value of each player for each season in baseball history is thought-provoking and worthwhile. Bill James's work on analyzing fielding statistics is incredibly useful and important.

I have a major criticism with the win shares system, however, and I hope I'll be able to express it adequately in writing. My problem is this. Win shares are based on the idea that a player contributes offensively to the runs that the team scores and defensively to limiting the runs the team allows. What James does, however, is start with the total number of wins for a team -- e.g., 97 for the 1977 Baltimore Orioles -- and then he takes as a fundamental premise that the Orioles as a team created 291 win shares. He then allocates those win shares to the offense, the defense, and the pitching, and then calculates each player's "share" of the team offense, the team defense, and the team pitching -- adding the total together for each player. For instance, Ken Singleton gets 36 win shares for the 1977 Orioles.

Here's the problem. Based on the total number of runs the Birds scored that year and the total runs they allowed, and using the "Pythagorean" formula popularized by James himself, Baltimore should have only gone 88-73 in 1977. So there should have been only 264 win shares to go around, not 291. That's a difference of 9%; accordingly, I would submit, Singleton should only get 33 win shares, not 36.

By contrast, take the 1972 Orioles, who actually went 80-74, but whose Pythagorean won-lost mark is 90-64. James's system allocates 240 total win shares to the team that year, instead of 270 -- a 12% percent difference. And therefore, Jim Palmer, who James gives 24 win shares for that year, should get 27. This makes a big difference; the James win share system gives Singleton's 1977 season a 12-win share advantage over Palmer's, but the Pythagorean system would peg the difference at only 6.

What's wrong, you ask, with assigning win shares based on actual wins instead of Pythagorean wins? Because in reality, the difference is simply a matter of luck. Over a five-year period, a team's actual and Pythagorean won-lost records will almost always be the same. The fluctuations come in one or two-year samples. Certain teams -- the 1977 Orioles, the 1975 Red Sox -- just get a lot of breaks. The ball bounces their way. And the win shares system should recognize that.

In fact, however, James not only doesn't recognize it, he compensates in the other direction. He gives Singleton (and all the 1977 Birds) extra credit for the fact that the team exceeded its Pythagorean projection. He briefly discusses this in the Snider/Mays essay in his book. I think this is a serious mistake.

The whole idea of tying the system to actual wins is a fiction, of course. Bill James doesn't know what Ken Singleton's statistics in 1977 were in the Orioles' 97 wins, as opposed to their 64 losses. It's theoretically possible that all of Singleton's production came in losses and was thus effectively useless to the team. We simply have to assume that every player's production is roughly proportionally distributed across the team's wins and losses; that assumption is built in to all analytical systems. That's why player evaluation is based on offensive runs created and defensive/pitching runs prevented. The Pythagorean system converts team runs scored and allowed into a won-lost record, and it is that record that should be the basis of the win shares system.

Rating:
Summary: Bill James the Genius
Review: This book is the sort of thing us stats geeks dream of. With Win Shares Bill James may have come closer than anyone else to developing a statistical system that objectively evaluates an individual player's performance. We already knew that Coors Field numbers don't mean as much relative to the rest of the league; but now we can figure out exactly what those inflated numbers mean. We can ask the question, "How good is Todd Helton?" and get a logical answer. Actually, he's pretty good, but he's no Lou Gehrig. More than that, we can ask "How good was Lou Gehrig compared with modern ball players?" Actually, he was pretty darned good, so good that James made him the top first baseman in his New Historical Baseball Abstract. This is not news, you may say. That's certainly right; but putting modern baseball players in a historical context, or vice versa, has been a deep well for fan argument for a hundred years or more. How do 1970's ball players stack up with 1930's ball players, or 1990's ball players? Win Shares gives an answer based on the logic that an individual's contributions to their team's win total is the most accurate way of measuring a player's performance. It's not a perfect system, which James takes great pains to illustrate; but he also illustrates at fascinating length how useful it is; as well as what it is (the complete statistical system is detailed in section II). If you are a baseball stats geek get this book.

Rating:
Summary: brilliant concept, somewhat flat execution
Review: We all know Bill James not just as the man who revolutionized the study of baseball statistics, but also as an overall first-rate mind able to extend his piercing observations well beyond the sphere of baseball alone. I'm a professional philosopher, and I always tell people, with no irony whatsoever, that Bill James was the first philosopher I ever read.

For those who read James' new Historical Abstract last year, with its hints at the seismic breakthrough of his Win Shares method, the present book seemed likely to be the most exciting thing that James ever wrote. It's not. Although the method itself is fascinating, I would agree with the reviewer who says that James seems to have lost some of the gusto of his earlier writing (however, that wasn't true of the revised Historical Abstract, so I suspect it's more a matter of deadline pressures on this book than the fatigue of age).

There's obviously a fantastic story behind this book-- James in November of 1996 suddenly reaching the intellectual insight that makes his win shares method possible. The story is told with too little drama. Worse yet, he does not linger enough over the reasoning behind the mathematical formulae he uses. In particular, he simply pulls the marginal runs method out of a hat, without clarifying in his usual lucid way why the mathematics behind this maneuver makes solid sense. For this reason it feels a bit arbitrary even as the reader watches the results of the method pan out convincingly well.

Overall, it feels less like a Bill James book than like a fantastic reference book with some Bill James footnotes added on. This book could have been one of the greatest classics of sportswriting history, but ends up just feeling like the first draft of a better book to come.