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RPA and OBP not calculated correctly

Posted: Tue Mar 08, 2011 12:22 pm
by edippel
We have tabulated scores for two games now, but it seems the RPA is correct for some players, but not all. For example we have one batter with 5 ABs and 2 runs. The stat sheet calculates his RPA as 0.500. Shouldn't it be 0.400? Another example is we have a player who has scored no runs at all, but has an RPA of 0.500. Is this a bug or am I not figuring this right?

Re: RPA and OBP not calculated correctly

Posted: Tue Mar 08, 2011 1:25 pm
by PetroGuy
RPA is calculated as hits + walks - homeruns divided by plate appearances or:

(H + BB - HR) / PA

FTM - I noticed the hover text on RPA on my team website shows "Runs per At Bat". That is a little misleading.

Re: RPA and OBP not calculated correctly

Posted: Tue Mar 08, 2011 1:54 pm
by FTMSupport
We actually are using "Runs Per At Bat (actually Per Appearance)" for RPA. The equation is:

(Runs + RBI - HR) / PA

There are other equations for RPA as well (like "Run Production Average" which can put weights on singles, doubles, triple, home runs, etc), but iScore is using the simple Runs Per At Bat.

This shows the number of runs generated by a batter per time they come to the plate. They get credit for any run the score, or any run the drive in. One plate appearance with a Grand Slam would be 4.0. Being a leadoff batter with nobody on base, the best you could ever do is a 1.0 if you got on base and/or scored every single time (no RBI potential).

We will likely be adding a way to view many additional statistics this season as well.

For the original poster, it sounds like maybe there was a walk or some other way of getting on base that would count as a plate appearance but not an At Bat, and the runner scored that time making it 3 runs scored in 6 Plate Appearances (or some other combination of Plate Appearances + RBI's + Runs Scored that makes a .500 avg).

Re: RPA and OBP not calculated correctly

Posted: Tue Mar 08, 2011 5:17 pm
by PetroGuy
Dang it, I meant RBI and not BB. Brain malfunction.

(I still think the hover text should read "Runs per Plate Appearance" though).

Re: RPA and OBP not calculated correctly

Posted: Tue Mar 08, 2011 5:27 pm
by FTMSupport
You are right... we will change that hover text now. Thanks.