The Red Sox won Game 5 of the World Series last night behind another stellar performance from Jon Lester and a balanced offense, with seven players reaching base and three having multi-hit games, plus no player having more than one run or RBI. They’re now one win away from a World Series title with two chances to get it, and they have homefield advantage as the Series moves back to Boston. So they should have this series just about wrapped up, right?
Not so fast. Just as we did when the Series went to St. Louis, let’s examine the history of the Fall Classic and see how World Series winners did in the past (assuming a 3-2 series).
The World Series at 3-2, Historically
Game 5 Win%
Game 6 Win%
Average Series Length
|World Series Winner||31-27||0.534||43-15||0.741||6.61 games|
Just as we saw with Game 2, the winner of the Series doesn’t tend to have a significant tendency to win Game 5. But Game 6 is hugely decisive, mostly because it’s a potential clinching game; the World Series winner has a high likelihood of winning Game 6 because the team that wins Game 6 often wins the World Series, so this is a case of reverse causation that ultimately tells us very little.
However, it does give us a chance to peg the Red Sox’ odds. We already know the Red Sox won Game 5, and 12 of the 25 teams that won Game 5 to take a 3-2 series lead also took Game 6. That gives the Red Sox a 48% chance to clinch tomorrow night, a bit lower than one might initially expect. All it really suggests, though, is that any given team has about a 50% chance of winning a World Series game because momentum is largely nonexistent, something we’ve known for quite some time.
Once things get to a Game 7, with the Series tied, just 19 of 35 championships went to the Game 5 winner. That’s a winning percentage of 54.3%, about we would expect, since the Series came down to a best-of-1 and that should be split evenly as well.
But the catch is Boston doesn’t have to win twice, just once. Taking the 52% chance to lose Game 6 and the 45.7% chance of losing Game 7, the Red Sox have just a 21.9% chance of losing both games and thus the Series, obviously leaving an 78.1% probability they end up hoisting a trophy. Not entirely overwhelming odds for the Cardinals, but close, and not something you’d include in your pregame motivational speech.
Making things worse is the fact that the Cardinals have to go on the road and win twice. Of the 20 teams who won both Games 6 and 7 regardless of Game 5, only seven of them did it on the road, meaning if the Red Sox had lost last night and thus were down 3-2 and coming home, they’d still have a decent chance of winning based purely on the fact that they’re at home. There’s a bit of good news in that St. Louis has a history of doing this, as two of their World Championships came after being down 3-2 on the road. Then again, they happened in 1926 and 1934, so the modern relevance is perhaps a bit lost. Finally, of the World Series that went seven games, the last nine have all gone to the team with home field advantage, as have seven of the last 10 that went six games.
It’s safe to say, then, that the Red Sox have a greater than 80% chance of winning the World Series at this point, considering that 78.1% figure is ignorant of home-field advantage and teams that come back from being down 3-2 tend to do so at home, which the Cardinals are not.