Game score is a metric devised by Bill James as a rough overall gauge of a starting pitcher's performance in a baseball game. It is designed such that scores tend to range from 0–100, with an average performance being around 50 points.
Formula
To determine a starting pitcher's game score: Start with 50 points. Add one point for each out recorded, so three points for every complete inning pitched. Add two points for each inning completed after the fourth. Add one point for each strikeout. Subtract two points for each hit allowed. Subtract four points for each earned run allowed. Subtract two points for each unearned run allowed. Subtract one point for each walk.
History
James first introduced game score in the edition of his Baseball Abstract. He called it "a kind of garbage stat that I present not because it helps us understand anything in particular but because it is fun to play around with."
Other versions
James has noted that there are cases in which his original version of game score does not accurately reflect a pitcher's performance.
In a September 2003 article in Baseball Prospectus, Dayn Perry created an updated formula based on the ideas behind defense-independent pitching statistics, named Game Score 2.0.
In December 2014, statistician Tom Tango made another attempt at updating the formula, which he also called "Game Score Version 2.0". This version applies a base of 40 points to starting pitchers' game scores (instead of 50), adjusts the point values of certain in-game events, and introduces a penalty for giving up home runs into the equation. Game Score Version 2.0 is the variant displayed on MLB.com. According to James, the original version of game score correlates more closely with team winning percentage and ERA than Tango's version.
Highest achieved scores
The highest game score for a nine-inning game in the major leagues is 105, achieved by Kerry Wood for the Chicago Cubs against the Houston Astros on May 6, 1998, in just his fifth major league start. Wood's performance included 20 strikeouts, zero walks, and just one hit.
The second highest nine-inning game score is 104, which occurred on October 3, 2015, when Max Scherzer of the Washington Nationals allowed no hits and no walks, striking out 17, against the New York Mets. This is also the highest game score ever for a major league no-hitter.
The 100th game score of 100 points or higher was pitched by Matt Cain in June 2012. Of the 100 such games, only ten of them were a regulation nine innings. Higher scores have been accomplished in extra-inning games. The two highest game scores ever recorded both occurred in the same game: the famous 26-inning duel from 1920, Joe Oeschger scored 153 and Leon Cadore scored 140. Oeschger had earlier scored a 102 in a 14-inning game in 1917 against Jeff Pfeffer, who scored 114. Oeschger's record in these games was 0–0, because both ended in ties and were called by darkness. In all, there have been nine games in which both starting pitchers scored 100 points; all required extra innings and none has occurred since 1971. Juan Marichal and Warren Spahn scored 112 and 97, respectively, during a complete game 16-inning match up on July 2, 1963; Spahn's score fell below 100 because of Willie Mays' game-winning home run in the bottom of the 16th.
Twenty-one pitchers with 100 or more game score points did so in losing games, including Harvey Haddix, who scored a 107 for the game in which he took a perfect game into the 13th inning. The highest-ever losing game score was 118, from Art Nehf, who outlasted the opposing starter by six innings but lost in the 21st inning. Seventeen of the 100+ game scores came in suspended tie games. Only seven of the 100 highest game scores were no-hitters.
Walter Johnson and Nolan Ryan had the most 100-point game scores with four apiece. Johnson had two in 1918, one in 1919, and a fourth in 1926; Ryan's came in 1972, 1973, 1990 and 1991. Warren Spahn had three 100-point game scores, in 1948, 1952 and 1960. Juan Marichal had three 100-point game scores, in 1963, 1966 and 1969. Eight pitchers had two 100-point game scores: Art Nehf (1917 and 1918), Joe Oeschger (1917 and 1920), Burleigh Grimes (1918 and 1920), Eric Erickson (1918 and 1921), Herb Pennock (1923 and 1925), Jim Maloney (1964 and 1965), Frank Tanana (1975 and 1976), and Max Scherzer (both 2015).