Selling Furniture by Selling a "Sweep" of the World Series

Those of us who live in the Boston area remember at least two things from the 2007 World Series: Jonathan Papelbon striking out the last batter on a called strike three in game 4 to win the championship - a feeling of unbridled joy and; realizing that we hadn't bought any furniture at Jordan's Furniture during their free furniture promotion if the Red Sox won it all - a feeling of unbounded regret.

This year, the furniture store is running a similar promotion - if the Red Sox win it all in a sweep - winning it all in the fewest number of games - you get your furniture free. This, of course, was provided through the wonders of insurance. One can imagine how expensive that insurance plan this year without the "Sweep" caveat in the "Monster Sweep."

The ad campaign, voiced by "Red Sox Nation President," former Sox infielder, and all around media guy Jerry Remy, suggests that "since 1989, 39% of world championships have been decided in a sweep."

Armed with some knowledge of statistical analysis and of baseball history - always a dangerous combination - I immediately recognize the flaw in this promotion: 1989 is a VERY arbitrary date in baseball history.

1989 - No playoff structure changes; an 18-series span. Peculiar. Must be something particular to this 18-series/19-year period (remember, 1994 had no world series).

Well, upon review of the history of world series winners we see what that peculiarity would be: 1989 was the first series sweep since 1976, followed by another in 1990. Also the sharp listener will realize that 39% of 18 is 7. Doesn't sound like a particularly convincing argument, or really a statistically significant one.

Over a 20-series period: 1987-2007, the same 7-series were sweeps. Had they simply used the phrase "over the last 20 world championship series, 35% were won in a sweep," I probably wouldn't have even thought twice.

There have been some significant structural changes to Major League Baseball's playoff structures over the years, so I thought we should look at this some more:

In 1995 - a new playoff structure was implemented (it was to have been used in 1994, but the strike precluded that) using three divisions and a wild card in each league. Since the addition of a "Divisional Round" of the playoffs, 41.6% of world series championships have been decided in sweeps. Then again, that's only 12 championship series. It is too early to tell, but it would seem that MLB has traded a quality world championship series for the potential of an additional 20 playoff games and increased fan interest for more teams.

In 1969 each league was split into divisions for the first time, creating a playoff for the first time. There were only 3-sweeps in the 25-series' between then and the inception of the wild card (1976, 1989, 1990) of a mere 12%, and in the 38-series' there have been 8-sweeps, or 21% decided in as few a number of games as possible.

So, what of the "pre-playoffs" world series champions?

From the inception of the World Series through 1968, the team in each league with the best record automatically advanced to the World Series. 65-World Series'. 12-sweeps. The first was in 1907 when the Chicago Cubs (of all teams) defeated the Detroit Tigers; the next year, the Tigers fared a little better winning 1 game from the defending World Series Champion Cubs. The first 3-sweeps were won by the National League. The next 6 were won by the New York Yankees, in fact the Yankees have won 8 of the 20 sweeps in World Series history.

Which leads to the next and final stat. Of the 103-World Series played, 19.4% have been won in a sweep. And just in case you're wondering, 39 series' have gone the maximum number of games (in which 7 games has been the maximum number 36 of those times)

So, Jordan's Furniture had the right idea in framing the conversation around a specific data set - over the history of baseball only 19% have been sweeps vs. about 38% of series going to the max number of games. The data set which would have most positively accentuated their point, though, would have been those World Series' that have been played under the current playoff structure: although a small sample size (and when has statistical significance ever really mattered in advertising) the proportion of sweeps in the World Series have increased in the current playoff structure - almost 42% of the time. Had they chosen the less awkward "20" World Series', their number would have decreased by only a couple of per cent to 35%. Perhaps not even an either/or - how convincing an argument would it have made to point out that sweeps have been increasing over the last 20 or 12 championship tilts?

Sadly for Sox fans and those of us who may still need furniture, none of these numbers mean the Red Sox have any greater chance to repeat as champions in a sweep.

RESOURCES:

http://www.championshiphistory.com/mlb.php

http://www.associatedcontent.com/article/701689/why_is_the_world_series_a_bestof7_series.html

http://en.wikipedia.org/wiki/Jordan's_Furniture