Boston Red Sox: Where does the 2018 rank all time in team history?

BOSTON, MA - OCTOBER 31: Red Sox Mookie Betts hoists the World Series Trophy on the Rolling Rally Parade in Boston on Oct. 31, 2018. (Photo by Stan Grossfeld/The Boston Globe via Getty Images)
BOSTON, MA - OCTOBER 31: Red Sox Mookie Betts hoists the World Series Trophy on the Rolling Rally Parade in Boston on Oct. 31, 2018. (Photo by Stan Grossfeld/The Boston Globe via Getty Images) /

The 2018 Boston Red Sox team was very good, but were they the best in team history? A mathematical analysis

Since the Boston Red Sox clinched their World Series victory over the Los Angeles Dodgers Sunday night, the baseball world has been consumed by a single question: Is this the best Red Sox team in franchise history?

Opinions have flown more or less constantly on the MLB Network, at, on ESPN, on, in USA Today, and even in the U.S. version of the British Manchester Guardian’s website. Within just the past few days, all have published pieces speculating on the 2018 Sox’ ranking among the great Boston teams, with a particular emphasis on the post-2000 era.

The problem with all their various conclusions is that they have been subjective; that is, they’ve presented somebody’s opinion. And opinions, as we’ve all been taught, are like certain body parts that shall go unspecified here for reasons of decorum.

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What is need is an objective methodology that can be used to order the various great Red Sox teams. The results presented below use such a methodology. Rather than being based on perceptions, it’s based on an utterly objective measure: the standard deviation of run differential over the course of each full season.

Run differential is used because outscoring opponents is what baseball is all about, and run differential measures that ability. Standard deviation is used because it normalizes all the elusive stylistic changes that otherwise make cross-era comparisons so problematic.

For purpose of reference, a score of one standard deviation above the seasonal average means that a team’s scoring margin was better than approximately two-thirds of all teams encompassed in the rating. At two standard deviations, we are talking about a team likely to be produced two or three times in 100. Approach 3 standard deviations and we’re solidly inside “1 in a 100” levels of exceptionality.

The Red Sox began playing ball in 1901, meaning the franchise has been around for 118 seasons. The following list of the top 10 Boston Red Sox teams is culled from the standard deviation scores of all 118. That means it considers not just the World Series champions, not just the pennant winners, but even those Red Sox teams that failed to qualify for post-season play at all. Indeed, one of the 11 teams in the top 10 – there was a flat tie for 10th place – did not play a single post-season game.

The rating does appear  to verify one bias that has held more or less consistently through all of the recent spate of subjective orderings of the great Boston teams: a consensus that the champions since 2004 have been uniformly superior to all of the franchise’s previous entries. The top three teams on the list below all are among Boston’s four World Series champions of the past 15 years. Beyond that, all four are among the all-time top 10.

Here’s the list.

Season                    Record    Place       Post-season                     St. Dev.

  1. 2007               96-66     1st           Won World Series            2.22
  2. 2013               97-65     1st           Won World Series            1.97
  3. 2018             108-54     1st           Won World Series          1.81
  4. 2016               93-69     1st           Lost ALDS                           1.79
  5. 2008               95-67     2nd          Lost ALCS                           1.60
  6. 2004               98-64     2nd          Won World Series            1.55
  7. 1912             105-47     1st           Won World Series            1.53
  8. 1903               91-47     1st           Won World Series            1.49
  9. 1946             104-50     1st           Lost World Series             1.46

T-10 2002               93-69     2nd          Did not qualify                   1.42

T-10 2009               95-67     2nd          Lost ALDS                            1.42

So although it won the most games, the 2018 version is not objectively the best Red Sox team ever– that honor belongs to the 2007 World Series champs — but it’s solidly in the conversation. Perhaps surprisingly, the 2004 Sox — probably favored by many since it was the first in 86 seasons to actually win the World Series — rank only sixth, behind a couple teams that did not even play in the World Series.

A few words about the 2002 team that did not reach post-season play. In fairness, it did finish second in the AL East to a very good Yankee team, and lost its wild card spot only because the Oakland A’s won 103 games and the Angels won 99.

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For the record, here’s how Boston’s other World Series teams throughout history rated:

  • 1915: 0.85
  • 1916: 0.50
  • 1918: 1.28
  • 1967: 1.23
  • 1975: 0.79
  • 1986: 1.33