Win Shares
Encyclopedia
Win shares is the name of the metric Bill James
describes in his 2002 book Win Shares
.
It considers statistics
for baseball
and basketball
players, in the context of their team and in a sabermetric way, and assigns a single number to each player for his contributions for the year. A win share represents one-third of a team win, by definition. If a team wins 80 games in a season, then its players will share 240 win shares. The formula for calculating win shares is complicated; it takes up pages 16–100 in the book. The general approach is to take the team's win shares (i.e., 3 times its number of wins), then divide them between offense and defense.
In baseball, all pitching, hitting and defensive contributions by the player are taken into account. Statistics are adjusted for park, league and era. On a team with equal offensive and defensive prowess, hitters receive 48% of the win shares and those win shares are allocated among the hitters based on runs created
. An estimation is then made to decide what amount of the defensive credit goes to pitchers and what amount goes to fielders. Pitching contributions typically receive 35% (or 36%) of the win shares, defensive contributions receive 17% (or 16%) of the win shares. The pitching contributions are allocated among the pitchers based on runs prevented, the pitchers' analogue to runs created. Fielding contributions are allocated among the fielders based on a number of assumptions and a selection of traditional defensive statistics.
In Major League Baseball, based on a 162-game schedule, a typical All-Star might amass 20 win shares in a season. More than 30 win shares (i.e. the player is directly responsible for 10 wins by his team) is indicative of MVP-level performance, and 40+ win shares represents an exceptional, historic season. For pitchers, Win Shares levels are typically lower—in fact, they often come close to mirroring actual wins.
Win shares differs from other sabermetric player rating metrics such as Total player rating
and VORP
in that it is based on total team wins, not runs above replacement.
Within the sabermetric community there is ongoing debate as to the details of the system. The Hardball Times
has developed its own Win Shares, as well as a number of derivative statistics, such as Win Shares Above Bench, Win Shares Percentage, Win Shares Above Average, and All Star Win Shares.
players as well as baseball players.
Bill James
George William “Bill” James is a baseball writer, historian, and statistician whose work has been widely influential. Since 1977, James has written more than two dozen books devoted to baseball history and statistics...
describes in his 2002 book Win Shares
Win Shares (book)
Win Shares is a book about baseball written by Bill James and Jim Henzler, published by STATS, Inc. in 2002.As ESPNs Jim Baker put it, "we've been talking about Win Shares, the baseball metric Bill James introduced in .... a book titled, oddly enough, Win Shares. It explains the concepts of win...
.
It considers statistics
Baseball statistics
Statistics play an important role in summarizing baseball performance and evaluating players in the sport.Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itself to easy record-keeping and statistics...
for baseball
Baseball
Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...
and basketball
Basketball
Basketball is a team sport in which two teams of five players try to score points by throwing or "shooting" a ball through the top of a basketball hoop while following a set of rules...
players, in the context of their team and in a sabermetric way, and assigns a single number to each player for his contributions for the year. A win share represents one-third of a team win, by definition. If a team wins 80 games in a season, then its players will share 240 win shares. The formula for calculating win shares is complicated; it takes up pages 16–100 in the book. The general approach is to take the team's win shares (i.e., 3 times its number of wins), then divide them between offense and defense.
In baseball, all pitching, hitting and defensive contributions by the player are taken into account. Statistics are adjusted for park, league and era. On a team with equal offensive and defensive prowess, hitters receive 48% of the win shares and those win shares are allocated among the hitters based on runs created
Runs created
Runs created is a baseball statistic invented by Bill James to estimate the number of runs a hitter contributes to his team.-Purpose:James explains in his book, The Bill James Historical Baseball Abstract, why he believes runs created is an essential thing to measure:With regard to an offensive...
. An estimation is then made to decide what amount of the defensive credit goes to pitchers and what amount goes to fielders. Pitching contributions typically receive 35% (or 36%) of the win shares, defensive contributions receive 17% (or 16%) of the win shares. The pitching contributions are allocated among the pitchers based on runs prevented, the pitchers' analogue to runs created. Fielding contributions are allocated among the fielders based on a number of assumptions and a selection of traditional defensive statistics.
In Major League Baseball, based on a 162-game schedule, a typical All-Star might amass 20 win shares in a season. More than 30 win shares (i.e. the player is directly responsible for 10 wins by his team) is indicative of MVP-level performance, and 40+ win shares represents an exceptional, historic season. For pitchers, Win Shares levels are typically lower—in fact, they often come close to mirroring actual wins.
Win shares differs from other sabermetric player rating metrics such as Total player rating
Total player rating
Total player rating , also known as Batter-Fielder/Pitcher Wins is a metric for measuring the value of baseball players, and to enable players to be compared against each other even when they played for different teams, at different positions, and in different eras...
and VORP
Value over replacement player
In baseball, value over replacement player is a statistic popularized by Keith Woolner that demonstrates how much a hitter contributes offensively or how much a pitcher contributes to his team in comparison to a fictitious "replacement player," who is an average fielder at his position and a below...
in that it is based on total team wins, not runs above replacement.
Criticism of win shares
- Players cannot be awarded "loss shares", or negative win shares, by definition. Some critics of the system argue that negative win shares are necessary. In defense of the system, proponents argue that very few players in a season would amass a negative total, if it were possible. However, critics argue, when one player does amass a negative total, he is zeroed out, thus diminishing other players' win-share totals. In an attempt to fix this error, some have developed a modified system in which negative win shares are indeed possible.
- The allocation of win shares 48% offense and 52% defense is justified by James in that pitchers typically receive less credit than hitters in win shares and would receive far too few win shares if they were divided evenly.
- One criticism of this metric is that players who play for teams that win more games than expected, based on the Pythagorean expectationPythagorean expectationPythagorean expectation is a formula invented by Bill James to estimate how many games a baseball team "should" have won based on the number of runs they scored and allowed. Comparing a team's actual and Pythagorean winning percentage can be used to evaluate how lucky that team was...
, receive more win shares than players whose team wins fewer games than expected. Since a team exceeding or falling short of its Pythagorean expectation is generally acknowledged as chance, some believe that credit should not be assigned purely based on team wins. However, team wins are the bedrock of the system, whose purpose is to assign credit for what happened. Win shares are intended to represent player value (what they were responsible for) rather than player ability (what the player's true skill level is).
Within the sabermetric community there is ongoing debate as to the details of the system. The Hardball Times
The Hardball Times
is a website which publishes news, original comments and statistical analysis of baseball each week Monday through Friday, in addition to the Hardball Times Annual book which features essays by leading sabermetric personalities. The website features the slogan "Baseball. Insight...
has developed its own Win Shares, as well as a number of derivative statistics, such as Win Shares Above Bench, Win Shares Percentage, Win Shares Above Average, and All Star Win Shares.
Basketball
Win shares has recently been applied sabermetrically to basketballBasketball
Basketball is a team sport in which two teams of five players try to score points by throwing or "shooting" a ball through the top of a basketball hoop while following a set of rules...
players as well as baseball players.
External links
- Sortable Win Shares for 200-2008 MLB - The Hardball Times
- "Fun With Win Shares", a blogBlogA blog is a type of website or part of a website supposed to be updated with new content from time to time. Blogs are usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video. Entries are commonly displayed in...
featuring current win shares analysis and full 20032003 in sports2003 in sports describes the year's events in world sport.-Alpine skiing:* Alpine Skiing World Cup** Men's overall season championship: Stephan Eberharter, Austria** Women's overall season championship: Janica Kostelić, Croatia-American football:...
win shares totals. - Three articles criticizing win shares