Fans of teams bound for the postseason freak out if that team is struggling in the last days before the playoffs start. Obviously, ending the season on a winning streak will result in confidence in a fan base. As is often the case, the emotions of fans aren’t rooted in actual fact.
To discover the truth of the situation, I took the last 19 seasons of World Series match-ups and looked at how both teams did in their final 10 games of that particular regular season. The reality is that recent history shows that whether a team is on a losing or winning streak going into the postseason has very little bearing on the ultimate goal of winning a World Series.
Last season, the San Francisco Giants won just four of their last 10 games of the regular season. They went on to not only advance to the Fall Classic, but defeat the Kansas City Royals in seven games to win the 2014 World Series. Kansas City, by the way, had finished its 2014 regular season schedule by winning six of its last 10 games.
In fact, the last three consecutive World Series champions – 2014 Giants, 2013 Boston Red Sox and 2012 Giants – all went .500 or worse over their last 10 regular season games. In all three of those instances, they defeated teams who had winning records in their last 10 regular season games. Limiting a data sample to just those seasons, the sample would say that it’s actually better to be on a cold streak to finish the season as far as winning the World Series goes.
The bigger sample of the last 19 seasons tells a fuller story. The 2014 Giants are one of nine teams over the past 19 seasons who have finished their regular season schedule with no more than five wins in their last 10 games to go on and win a World Series anyway. That’s 47 percent of this grouping of World Series champions, showing that there is a weak correlation between ending the regular season on a winning streak and winning the World Series in that same season.
As a reminder, a weak correlation does not mean that something is unlikely to happen. It means that the phenomena being compared seem to have no effect on each other.
Being scorching hot to end the regular season does seem to be a bad omen in this data sample, however, to where winning a World Series championship is concerned. Three American or National league champions (2011 Texas Rangers, 2007 Colorado Rockies, 2002 Giants) over the past 19 seasons have finished the regular season 9-1 in the last 10 games. All three lost the World Series. The six such teams in this sample who went 8-2 in their last 10 games won the World Series twice and lost the Fall Classic four times.
The story changes a little when considering simply reaching the World Series, however. Of the past 38 teams to reach the World Series over the last 19 seasons, only 14 (37 percent) of them went .500 or worse over their last 10 regular season games. The data shows a stronger correlation between finishing the regular season on a roll and winning a League Championship Series, though 63 percent isn’t really a strong correlation by most statistical standards.
Naturally, there are many more elements, some of which can’t easily be quantified, that go into whether or not a team reaches and/or wins the World Series in a particular season. What this data tells us is that for the past 19 teams who have accomplished both objectives, whether or not they finished the regular season on a roll had very little if any effect on their postseason destiny.