No Chance: '39 Yankees and '06 Cubs Dominated the Scoreboard
Although they were "only" 106-45 that year, many baseball historians and researchers consider the 1939 Yankees as having had the greatest single season of any team in major league history, and not the far-more-famous 110-win 1927 Yankees (the team with the Babe and his 60 home runs and Gehrig) or the far-more-recently-famous 1998 Yankees (winners of 125 games including the post-season and featuring the incomparable Jeter and Rivera in their youth). Giving up just 556 runs, the '39 Yankees were not just the only American League team that season to allow fewer than 600 base runners to cross the plate against them, they were the only AL team to allow fewer than 700. (The Indians gave up exactly 700 runs.) With outstanding pitching and defense--particularly up the middle--the Yankees led the league in complete games, shutouts, saves, lowest on-base percentage and batting average against them, not to mention earned run average. And despite the completely unexpected loss of Lou Gehrig, who was forced from the line-up very early in the season with amyotrophic lateral schlerosis, the Yankees led the league in scoring with 967 runs--9 percent more than the runner-up (in both the standings and in scoring) Red Sox.
All told, the 1939 New York Yankees scored a phenomenal 411 runs more than their game opponents, an average of 2.7 runs per game. They won 41 of their 106 games by a blowout margin of five runs or more. The closest any major league team came to the Yankees in outscoring their opponents were the National League pennant-winning Cincinnati Reds, who scored an average of 1.1 run per game more than they gave up. The Cleveland Indians were the closest any American League team came to the Yankees in run differential, outscoring their opponents by just .63 runs per game. The more famous 1927 Yankees, for comparison, averaged 2.4 runs per game more than their opponents--the second highest per-game scoring advantage in modern major league history. But only two other times in the ten years Ruth and Gehrig started together in the Yankees' Murderers' Row did the Bronx Bombers even approach outscoring their opponents by two runs per game--in 1931 (at 1.98) and in 1932 (at 1.8).
The 1939 Yankees were the bravura final act of the most dominant four-year stretch in baseball history, averaging 103 wins per the 154-game schedule since 1936. They had won four straight pennants, all of them so decisively that the AL races were effectively over by September. They dominated every facet of the game. In all four of those years they were first in the league in scoring. In all four of those years they also led the league in fewest runs allowed. In 1936 the Yankees outscored their game opponents by 334 runs, in 1937 by 308 runs, in 1938 by 256 runs. From 1936 to 1939, the Yankees scored 51 percent more runs than they surrendered, averaging 2.1 runs per game more than their opponents. And they won four straight World Series, during which they outscored their National League opponents by 61 runs in 19 games, a 3.2-to-1 per-game scoring advantage.
A third-of-a-century before, in 1906, the Chicago Cubs led the National League in scoring with 704 runs--substantially more than the 625 runs scored by the runner-up Giants--and in allowing only 381 runs against them, 89 fewer than the Pirates. Their favorable run differential of 323 runs meant they outscored their game opponents by 85 percent, an even higher percentage than the 74 percent more runs scored by the 1939 Yankees, and in fact the highest percentage in modern baseball history. Because this was the dead ball era, however, and there were 25 percent fewer runs scored in 1906 by the same number of major league teams playing the same-length schedule, the '06 Cubs averaging 2.1 runs per game more than they surrendered pales in comparison to the '39 Yankees' 2.7 runs-per-game average.
The achievements of the 116-win 1906 Chicago Cubs are sometimes diminished by virtue of their playing in the dead ball era. The fact that they were heavily favored to crush the cross-town Hitless Wonders White Sox in the World Series but fell to them relatively meekly in six games certainly did not help the '06 Cubs' reputation. From 1906 to 1910 the Cubs made the case for being the most dominant team in National League history over any five-year period. They won four pennants in five years, averaging 107 wins per 154-game schedule; the only season they won fewer than 100 was in 1908 when they missed by one; with exceptional pitching and defense (Tinker-to-Evers-to-Chance, anyone?) they gave up the fewest runs in the league four times in those five years; and although they led the league in scoring only once, they were a close second the four others years, 1907-10. All told, the Cubs averaged 1.45 runs per game more than their game opponents over those five years, again a pale comparison to the 1936-39 Yankees.
Major league baseball has not lacked for great teams in single seasons or teams that were dominant in their league over five or more seasons since the Second World War. At the same time, however, the disparity in player-talent level has narrowed, which means the competitive gap between the dominant teams since then and the rest of the league has also narrowed; even the worst teams are not as bad relative to the rest of the league as was the case for most of the first half of the 20th century. And changes in game strategy and roster makeup, particularly increasing reliance on relief pitching leading to greater specialization in bullpens, have greatly diminished the possibility of any team dominating the scoreboard in the way the 1939 Yankees and 1906 Cubs did, let alone the extent to which those teams did over four or five years.
Of the most recent "dynastic" teams, only the 1998 Yankees, who led the league in scoring and fewest runs allowed, have approached a 2-to-1 advantage in runs per game, with their scoring differential of 309 runs amounting to 1.9 runs per game more than their game opponents. Last year, the World Series champion Red Sox outscored their game opponents by 1.2 runs per game and the National League pennant-winning Cardinals outscored theirs by 1.15 runs per game.