Introducing ROB – Runs on Base

 

 

Yep, I’m going to introduce yet another stat into the Mop Up Duty glossary. Speaking of a glossary, expect one explaining our usually phrases and stat descriptions later next week.

 

Ok, so you have the stat BOB (modified contact rate, Bat on Ball %), so what exactly is the ROB stat? Well, right off the bat (ha ha), the ROB (Runs on Base) is far from perfect, so if you wish to dispute it’s validity, than by all means say so in the comment section.

 

 

 

The equation for the ROB is as follows;

(Hits + Walks + HBP) – HR
(Runs – HR)

 

The reasoning and explanation is as follows. I’m looking to see which players score most often (and least often) when they are on base safely. To get this, we add up all of the occasions that a player ends a plate appearance standing safely on a base. Adding up his hits, walks, and hit by pitch shows us how many times he’s standing safely on a base, excluding fielders choices. (I cannot find a fielders choice statistic, but if you have one, please let me know where to find it in the comments section.) After adding up those stats, we subtract home runs, as the player scores himself on the play. Then we subtract his total runs minus home runs to get the final total. The total will represent the number of times on base per run scored. Obviously, the lower the ratio is the better, as you would rather have a player that scores once every three times that he is on base (3.0), than a player that scores once every five and a half times (5.5). A two+ point difference may not seem like too big of a deal at first, but then you have to consider how many times a player is on base per season. Most likely my explanation is a bit confusing, so I’ll use the example of Brian Giles in 2006.

 

(Hits (159) + Walks (104) + HBP (5)) – HR (14)
/
Runs (87) – HR (14)

 

= 254 / 73 = 3.48 times on base per run scored

 

As I’ve previously stated, this equation is far from perfect. It doesn’t take into account fielders choices. It also leaves out advancements from stolen bases, where a player hits in the batting order, and the ability of his teammates to knock him in.

 

Yet when the numbers are run, we end up seeing a pretty obvious trend between the players with speed (shown mostly through stolen base attempts) and those without. Here are the top and bottom 15 in ROB during the 2006 season, with a minimum of 300 plate appearances.
 

Top 15

 

 

Bottom 15

 

 

 

The majority of the leaders group posses plus speed, and high spot in their batting orders, ensuring more runs. But I was surprised with the power numbers of the group, as four players within this group hit more than 20 home runs. The bottom group consisted almost exclusively slow runners, high power players, and a handful of catchers. A large number of the non-catchers on the list hit in the middle portion of their team’s respective batting orders. But, as you can see, this group possessed almost no stolen bases, and little speed overall. The bottom 15 group can also create a few questions as to the overall importance of OBP for slow runners. Three members of the bottom group had OBP % over .380. Yet none of them scored over 50 non HR runs (Howard: 104Runs-58HR = 46, Rameriz=44 Thomas=38). Only two players in the top group had OBP% of over .370, but they scored far more ROB runs (Beltran: 127Runs-41HR=86, Sizemore=106). 

 

Is a player’s position in the batting order the sole explanation to these numbers? Or does a player’s speed have something to do with the amount of runs he scores while on base? Is it a mixture?

Matthias Koster

VIsit Matthias Koster's website