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How Do Ultimate Base Runs and Equivalent Base Running Runs Compare?

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Today, Fangraphs added Mitchel Lichtman's Ultimate Base Runs (UBR) to their site. Baseball Prospectus also has a base running statistic that tracks base runners since 1950, called Equivalent Base Running Runs (EQBRR). Each of these statistics attempt to measure the impact a player has on the basepaths, in order to gain a better perspective of the player as a whole. The data for UBR go back to 2002, so let's look at each of these stats for players from 2002-2011.

*Colin Wyers brought to my attention that UBR excludes SB/CS, while EQBRR includes this data. Since this is the case, I have subtracted EQSBR from the EQBRR data.

 

There are 1,776 players with base running statistics on both Fangraphs and Baseball Prospectus. These are their stories.

 

Ubreqbrr_medium
Click to make the picture readable

 

UBR and EQBRR are pretty similar on most players. The average difference between players is 0.012 runs. The average run value for UBR is 0.037. The average for EQBRR is 0.025.

But most interesting -  where are the big differences?

 

 

Players that UBR rates much higher than EQBRR:

 

Ubrlikes_medium

 

 

Players that UBR rates much lower than EQBRR:

 

Eqbrrlikes_medium

There are 125 players with the exact same run value (my apologies for not listing them all). All of these players have a run value between -2 and 2.

 

Ubreqbrrspread_medium
Click to make the picture readable 
 

 

Both EQBRR and UBR have a similar spread. EQBRR has a few outliers that UBR does not have. It also looks like UBR flattens out more in the -2 to -5 range than EQBRR does.

 

There are quite a lot of similarities, which is comforting. EQBRR has a few more outliers and slightly lower values on average.