In playoffs, one-game momentum a myth
Whenever an MLB team trailing in a postseason series pulls out a big win, we say the series’ momentum has swung.
It makes obvious fodder for discussion for anyone following postseason baseball, from the casual fan at the water cooler to the seasoned analyst on television. I’ve certainly been guilty of it myself, and anyone could dig up countless examples of this author stating that playoff wins such as the New York Yankees’ series-evening victory in Boston might represent some greater change in the course of the series.
One issue: The notion of “momentum” inside a short MLB postseason series does not exist, or at least seems impossible to identify with any evidence beyond the anecdotal. The truth more likely lies with the old baseball adage, attributed to longtime manager Earl Weaver, that momentum is as good as the next day’s starting pitcher.
I looked back at every postseason series from 2012 through 2017 to see if I could find any indication that momentum is a real thing. I tallied the number of times a team that won any game in a series won the next game in the series.
I essentially totaled the won-loss record of teams coming off a postseason win. The first game of any series, here, establishes the momentum, but does not reflect whether momentum helped a team. So in the instance of a four-game sweep of a seven-game series, the team with momentum went 3-0. In a series like last year’s Chicago Cubs-Washington Nationals NLDS, in which the Cubs won Games 1, 3 and 5, the team with “momentum” went 0-4.
I used 2012 as an endpoint for a couple of reasons. That was the first year of the current postseason format, in which two wild-card teams per league play for entry into the proper playoffs. I did not incorporate the results of wild-card games.
From 2012 to 2017, there were 204 total MLB postseason games across 42 playoff series. Since Games 1 did not count for this exercise, that leaves exactly 162 games in which one club had momentum within a series. And teams coming off a win in the series were 80-82 in the following games.
Momentum, as we define nothing.
The team with momentum inside a postseason series wins the next game only about half the time, and this really shouldn’t be a surprise.
The odds on any individual baseball game between two good teams are pretty much a coin toss.
Mathematician Leonard Mlodinow’s well-reasoned claim is that it would require a best-of-269-game series to prove one MLB team capable of beating another one 55% of the time.
Even if postseason teams do get some boost from winning the previous night’s game, it’s not enough to overwhelm the randomness that dominates baseball, and so it’s not enough to reliably impact the next day’s final score.
Maybe using final game results does no justice to swings of momentum inside the games themselves, and maybe the it, means Yanks’ win against the Red Sox in Game 2 indicates a continuation of the momentum New York achieved by beating up on the Boston bullpen in the late innings of its Game 1 loss.
In 2004, Yankees fans were confident that their team would be moving on to the World Series when Mariano Rivera came in to close out the Red Sox. But the Sox tied the score against Rivera in the ninth.
Boston won that game and its next seven postseason games to take the World Series on a seemingly undeniable wave of momentum.
I’m not out to convince anyone that the 2004 Red Sox did not miraculously change the course of their postseason with that comeback in Game 4.
Viewed as a series of coin tosses, that one would mark three consecutive tails followed by eight consecutive heads — an eye-opening sequence, though not an impossible one.
But the value of momentum as we so often define it — in the case of the Atlanta Braves’ win against the Los Angeles Dodgers in Game 3 for example — is undoubtedly overstated. Baseball’s just not that straightforward.
The Dodgers wrapped up the series in Game 4.