Post-season winning percetange for the home team
Posted by Andy on October 9, 2009
I got curious about how big the edge is for post-season teams playing at home. This is actually pretty easy to research with the PI.
In post-season history through 2008, home teams have won 668 playoff games. I found that by doing a Pitching Game Finder search, limiting to playoff games, limiting to home team, and limiting to wins. At the bottom of the results page is the total number of such games. Doing the same for losses shows 560 such games. So there you have it--home teams in the playoffs are 668-560, which is a winning percentage of .548.
Let's compare that to the regular season. The PI covers only 1954 to present, and through 2008 the home team has won 58,958 games. Meanwhile they have lost 50,335. (I got these numbers also with Pitching Game Finders, just going on regular season games instead of post-season.) That's a winning percentage of .539.
So in the playoffs, historically, the home team has had a slightly bigger edge than they have during the regular season.
In the wild card era (1995 up to games through 2008) home teams in the playoffs are 243-207, a .540 winning percentage. In the regular season over that same span, home teams are 17,918-15,343, a .539 winning percentage.
It seems that the extra edge home teams once enjoyed in the post-season has been eradicated in the wild card era. It's interesting to wonder why this is the case.
Historically, the schedule was more balanced meaning that all teams played a similar schedule. That's different today, where teams play many more games within their own division, meaning that more balanced divisions tend to see more even records (think about the NL Central in recent years) whereas divisions with a couple of crummy teams tend to produce teams with lots of wins (think about the AL East, where bad Baltimore and, until recently, Tampa Bay teams allowed the Yankees and Red Sox to rack up great records.) This means that in the past, teams with a better record probably really were better, whereas these days the unbalanced scheule means a 95-win team may not be as good as an 85-win team.
So historically in the playoffs the teams with home-field advantage tended to be truly better teams whereas these days it's a little more random.
October 9th, 2009 at 8:43 am
Isn't it a recent thing that the better team got home field advantage? I thought the WS and later the LCS just rotated leagues and divisions for who was the home team. So I don't think this is the correct explanation.
October 9th, 2009 at 8:52 am
I'm not really trying to explain it--I'm just trying to say that today, you can't really judge which playoff team is better based only on record. I don't have the data, but I'm willing to bet if we seeded post-season teams (#1 has best regular season record, #2 has second best, etc) that #1 and #2 seeds used to win a lot more, and nowadays #3, #4 and even lower win more often than they used to.
October 9th, 2009 at 12:22 pm
You can get all-time home winning percentages using the Game Log Reports. http://www.baseball-reference.com/games/ Since 1901, the all-time home winning % is 54.2. From 1901-1953 it was 54.5.
October 9th, 2009 at 1:26 pm
I saw that teams in the alds go 14-14 after winning the 1st game, but in the nlds, they are 25-3.
1. why is there such a diference?
2. do you think these stats could hold true this year?
3. is there the same diference in the LCS?
4. is an AL team more likely to win a world series after losing the 1st game than an NL team who lost the 1st game?
October 9th, 2009 at 1:33 pm
Hmm that's interesting. Your questions #3 and #4 can be researched, of course. I don't know the answer to #1 though, and #2 would be pure speculation.
I mean--Boston certainly still has a decent shot of beating Angels despite dropping Game 1, whereas I think the Twins have little shot of beating the Yankees after losing Game 1. This has mainly to do with each team's regular-season record. For all their glory, the Twins are still just an 87-win team up against a 103-win team. So we could see 1-1 in the AL among teams who won the first game.
But I don't have any theories as to why there would be such a discrepancy between the leagues. There might be a discrepancy in home field advantage between leagues, but it couldn't possibly be large enough to explain the difference in series outcomes.