Inbaseball,run differential is a cumulative team statistic that combines offensive and defensive scoring. Run differential is calculated by subtractingruns allowed from runs scored.
Run differential is positive when a team scores more runs than it allows; it is negative when a team allows more runs than it scores. Non-zero run differentials are normally expressed with leadingplus and minus signs.
The final standings, along with runs scored (RS), runs allows (RA), and run differential (RD), of theAmerican League West for the1999 season were as follows:[1]
| Team | Won | Lost | Win pct. | GB | RS | RA | RD |
|---|---|---|---|---|---|---|---|
| Texas Rangers | 95 | 67 | .586 | – | 945 | 859 | +86 |
| Oakland Athletics | 87 | 75 | .537 | 8 | 893 | 846 | +47 |
| Seattle Mariners | 79 | 83 | .488 | 16 | 859 | 905 | -46 |
| Anaheim Angels | 70 | 92 | .432 | 25 | 711 | 826 | -115 |
Note: the run differentials shown above are notzero sum as the four teams within the AL West did not exclusively play against one another; there were 14 total teams in theAmerican League in 1999.
Run differentials may be used by some leagues or in some tournaments as a tiebreaker. An example isbaseball at the Summer Olympics, where if teams inpool play finish with identical records, run differential is used to determine which team advances to theknockout stage.[2] The1956 Claxton Shield tournament, held in Australia, included an instance of a team attempting to manipulate the run differential in order to advance.[3][4]
Major League Baseball (MLB) doesnot use run differential in breaking ties for postseason berths,[5][6] although standings presented on theMLB.com website may include run differential as a courtesy to the reader.[7]
Run differential has a strongcorrelation to a team'swinning percentage,[8][9][10] which is characterized by a formula known as thePythagorean expectation, devised byBill James.
A variation on the run differential formula is the Team Quality Balance (TQB) formula, defined by theWorld Baseball Softball Confederation (WBSC) for use in certain tie-breaking scenarios. It is calculated as runs scored per innings played on offense minus runs allowed per innings played on defense.[11] TQB functions the same as run differential except that it also factors in the number of innings played on offense and defense, which is not always the same. For example, when a home team is winning after8+1⁄2 innings have been played, the bottom of the ninth inning is not played; in such cases, the home team has played eight innings on offense and nine on defense, while the away team has played nine innings on offense and eight on defense.
The best run differential in a major-league season is +458, set by the1884 St Louis Maroons, who scored 887 runs while allowing 429.[12] The Maroons competed in theUnion Association, whose records and statistics are recognized by MLB. The worst run differential was by the1899 Cleveland Spiders of theNational League at −723, who allowed 1252 runs while only scoring 529.[13] In baseball's modern era (since 1900), the1939 New York Yankees have recorded the best run differential (+411),[14] while the1932 Boston Red Sox have recorded the worst (−349).[13]
The highest run differential in a single game in major-league history is 29, when theChicago Colts (now the Cubs) beat theLouisville Colonels 36–7 on June 29, 1897,[15] and the record in baseball's modern era (since 1900) is 27, when theTexas Rangers beat theBaltimore Orioles 30–3 on August 22, 2007.[16][17] The biggest run differential in ashutout is 22, when theCleveland Indians defeated the New York Yankees 22–0 on August 31, 2004.[18][19]
If Mexico wins, there will be a tiebreaker based on run differential.
It was reported Wednesday that run differential during the 2022 season would affect Postseason eligibility and seeding in the event of a tie. This is incorrect.