Baseball bumslayers

Analysts emphasize the importance of winning home games in every sport, and since home-road splits are easily accessible, glib conclusions are made that a good home record can be the ticket to the playoffs. While home dominance is important, it's not the only factor--how well do teams perform against opponents they're expected to beat?

The idea for this post came from a term coined by Jason Goff, host of The Night Show on Atlanta's 92.9 The Game. Prior to moving to Atlanta and when he still responded to my tweets he was a producer at 670 The Score in Chicago, and he coined the term "bumslayer" to describe the 2012 Chicago Bears. They began the season 7-1 by playing an underwhelming schedule and Jason called them bumslayers in that the teams they defeated weren't very good. He turned out to be correct as they were 3-5 in the second half of the season, missed the playoffs and cost coach Lovie Smith his job.

The notion intrigued me--which delivers more value, a good record at home or being a bumslayer and beating inferior teams? This table shows the data:

I gathered the data from a little-known recess of the Baseball-Reference.com Play Index called Situational Reports. For the years 2001-2013, teams were .541 in home games and .459 on the road, a difference of 82 points, a very healthy margin. However, when playing opponents with a losing record, teams were .561 vs. .439 against opponents with winning records, a difference of 122 points. Playing at home helped teams, but playing inferior opponents conferred a benefit around 50% greater than the home-field advantage.

Consider a series between the Cardinals and Marlins--regardless of whether it's played in St. Louis or Miami, St. Louis would be the prohibitive favorite, probably in every game Jose Fernandez didn't pitch. The Cardinals are the better team, which trumps any advantage the Marlins would glean by playing at home. For the Cardinals to make the playoffs, they need to defeat teams like the Marlins at a healthy rate, no matter where the game is played.

This table shows team for 2001-2013 (Washington includes the years in Montreal):

Click on column headings to sort

Arizona had a .535 record at home, .464 on the road, a 71-point difference, contrasted with a .554 record against losing teams and .443 against winning ones, a 111-point difference. Even the worst teams performed well against inferior opponents, but only three teams managed a record above .500 when playing good teams. Defeating good teams is hard, making it extremely important that inferior opponents are defeated as often as possible.

The road to the baseball postseason is paved by being a bumslayer--winning at home is important, but beating inferior teams is vital. The 2013 Royals were 10-9 against the decidedly-inferior White Sox and 2-5 against both the Angels and Yankees--if they had been 20-13 against these teams instead of 14-19 they might have made the playoffs. In the zero-sum world of professional sports, it's a clean dichotomy--teams are either bumslayers... or bums, destined to watch the World Series at home.

All data from Baseball-Reference.com

Follow Scott on Twitter at @ScottLindholm