As of this writing, the Houston Astros and the St. Louis Cardinals are preparing to meet in best-of-7 MLB/NBA/NHL playoff series 955 (the 2005 "National League Championship Series"). One year ago, these same two teams did battle in series 937 (the 2004 "National League Championship Series"), with St. Louis emerging victorious after the full seven games of a scintillating series. Naturally, St. Louis seeks to repeat their victory of last year, while Houston seeks to avenge last year's defeat. This Houston-St. Louis rematch gives rise to a question: When two MLB/NBA/NHL teams have met in consecutive-year best-of-7 playoff series, what outcome is more likely -- a repeat, or an avenging?

It happens that, in the history of MLB best-of-7 playoff series from 1905 through 2004, twelve times have the same two teams met in consecutive years. On six occasions did the first-year winner win in the second year. On six occasions did the second-year winner avenge its first-year loss.

The repeaters:

Atlanta Braves (defeated the Pittsburgh Pirates in the 1991 and 1992 MLB Semifinals ["National League Championship Series"]).

Chicago Cubs (defeated the Detroit Tigers in the 1907 and 1908 MLB Finals ["World Series"]).

New York Yankees (defeated the New York Giants in the 1936 and 1937 MLB Finals; defeated the Brooklyn Dodgers in the 1952 and 1953 MLB Finals; defeated the Los Angeles Dodgers in the 1977 and 1978 MLB Finals; defeated the Seattle Mariners in the 2000 and 2001 MLB Semifinals ["American League Championship Series"]).

The avengers:

Boston Red Sox (defeated the New York Yankees in the 2004 MLB Semifinals ["American League Championship Series"] after losing to them in the 2003 ALCS).

New York Yankees (defeated the New York Giants in the 1923 MLB Finals after losing to them in the 1922 MLB Finals; defeated the St. Louis Cardinals in the 1943 MLB Finals after losing to them in 1942; defeated the Brooklyn Dodgers in the 1956 MLB Finals after losing to them in 1955; defeated the Milwaukee Braves in the 1958 MLB Finals after losing in 1957).

St. Louis Cardinals (defeated the Philadelphia Athletics in the 1931 MLB Finals after losing to them in the 1930 MLB Finals).

Thus, St. Louis for series 955 finds favorable precedents in the 1992 Atlanta Braves, in the 1908 Chicago Cubs, and in the New York Yankees of 1937, 1953, 1978, and 2001. Houston finds favorable precedents in the 2004 Boston Red Sox, in the New York Yankees of 1923, 1943, 1956, and 1958, and in -- ironically -- the 1931 St. Louis Cardinals.

The other leagues:

Given the less-rigid playoff structures of the NBA and the NHL, it comes as no surprise to find far more consecutive-year best-of-7 playoff series rematches in those leagues. As noted above, the first-year MLB winner in best-of-7 playoff series had only a 6-6 (.500) rematch record. In the NBA, first-year winners had a 40-34 (.540) rematch record. In the NHL, first-year winners had a 68-44 (.607) rematch record. Through October 2005, there have thus far been three three-peats by an NBA team in best-of-7 playoff series in consecutive years against the same opponent: The Los Angeles Lakers defeated the Chicago Bulls in 1971, 1972, and 1973; the Philadelphia 76ers eliminated the Milwaukee Bucks in 1981, 1982, and 1983; the Detroit Pistons ousted the Chicago Bulls in 1988, 1989, and 1990. In the NHL, there have been nine such three-peats (Toronto over Detroit 1947-49; Detroit over Toronto 1954-56; Philadelphia over Toronto 1975-77; Montreal over Boston 1977-79; N.Y. Islanders over N.Y. Rangers 1981-83; Boston over Montreal 1990-92; Edmonton over Los Angeles 1990-92; Detroit over St. Louis 1996-98; and Toronto over Ottawa 2000-02. Also in the NHL, the Montreal Canadiens defeated the Boston Bruins in best-of-7 playoff series in 1952, 1953, 1954, and 1955, while the Dallas Stars achieved a similar four-peat over the Edmonton Oilers in 1998, 1999, 2000, and 2001. The MLB Houston Astros in 2005 thus have another incentive to avenge their 2004 loss to St. Louis: To avoid the possibility of becoming the first MLB team to suffer a three-peat best-of-7 series defeat to the same team in 2006.

11 October 2005