ReliefStat The Home of Relief Run Average

 

What happens if multiple pitchers inherit the same base runner in a single inning?
An inherited runner that scores can only be charged to the pitcher who is on the mound when that base runner scores. If that runner scored while the second relief pitcher was on the mound, the second relief pitcher will have an R.R.A.® above 0 for that appearance, while the first relief pitcher will have an R.R.A.® equal to 0.00 for that appearance (assuming no other inherited base runners scored).

How do you calculate R.R.A.® over multiple games?
To find a pitcher's R.R.A.® over multiple of games, for example a season, you need to find his mean R.R.A.® for that season.... Find the sum of all R.R.A.s® from that season, and divide it by the number of appearances with inherited runners over the course of that season.

Where does the multiplier constant of 1.55 come from?
The multiplier constant is used to make R.R.A. comparable to ERA. Based on the data set we evaluated, we concluded the that before using the multiplier, the median R.R.A. is 2.89, while the median ERA is 4.48. Dividing 4.48/2.89 we derived the multiplier 1.550 (rounded off to the nearest thousandth).

Where do the base factors come from?
The base factors are calculated from the ratios of inherited runners that have scored from each of the bases over the course of 20 years of regular season games. The percentage of inherited runners from each base is as follows: 1st Base: 20.47%, 2nd Base: 35.08%, 3rd Base: 52.00%. To make calculating R.R.A.® simple we set the 3rd base factor (R3) to 1.00. To be statistically accurate, the 2nd base and 1st base factors must reflect the precisely how much easier it is to prevent those runners from scoring (and therefore how much more the pitcher should be punished), therefore R2= (.5200/.3508) = 1.48 and R1 = (.5200/.2047) = 2.54.

 

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