PITCHING STAT FORMULA MISTAKE
Posted: Tue Jun 18, 2013 10:16 am
I do stats for teams at the high school level. I was recently going through how iScore calculates every single stat because I wanted to create my own stat sheet on Microsoft Excel. I would figure out how iScore calculated a particular stat and then research the same formula on many different sites, including MLB's website to make sure iScore's formula was correct. There was one stat so far where I may have found an issue. For pitchers, there is a run average and an earned run average, commonly known as RA and ERA. ERA is calculated as total number of earned runs divided by innings pitching multiplied by 9, the 9 representing the fact that baseball is a 9 inning game. In my case, my stats have that ERA and an ERA where the 9 is a 7 instead because games are 7 innings at the high school level. In fact, all my stats are calculated for 7 inning games. Now on to RA... Run average is almost identical to ERA. The difference is that the total number of earned and unearned runs are used in the formula instead of just earned runs. With that being said, below are example numbers of how they should be done and iScore calculates them. You should see that iScores way is incorrect.
Total Innings Pitched = 50
Total Unearned Runs = 15
Total Earned Runs = 10
Total Allowed Runs = 25
CORRECT WAY
9 inning bases ERA = 10 divided by 50 equals 0.2, 0.2 multiplied by 9 equals a 1.8 ERA
9 inning bases RA = 25 divided by 50 equals 0.5, 0.5 multiplied by 9 equals a 4.5 RA
I-SCORE WAY
9 inning bases ERA = 10 divided by 50 equals 0.2, 0.2 multiplied by 9 equals a 1.8 ERA
9 inning bases RA = 25 divided by 50 equals 0.5, giving you an RA of 0.5 (THIS PART IS WRONG)
What iScore does for the RA is cuts out the part where you have to multiply by 9, or 7 in my case. Unless a pitcher never gives up an unearned run, it's impossible for a pitchers RA to be lower than his ERA. You hear all the time about a pitcher having a great ERA but a bad record because of too many walks or defensive errors. Example: a pitcher could give up 5 runs in 9 innings, but only 1 of them were earned. He might get the loss or no decision but had a great ERA in that particular game.
Total Innings Pitched = 50
Total Unearned Runs = 15
Total Earned Runs = 10
Total Allowed Runs = 25
CORRECT WAY
9 inning bases ERA = 10 divided by 50 equals 0.2, 0.2 multiplied by 9 equals a 1.8 ERA
9 inning bases RA = 25 divided by 50 equals 0.5, 0.5 multiplied by 9 equals a 4.5 RA
I-SCORE WAY
9 inning bases ERA = 10 divided by 50 equals 0.2, 0.2 multiplied by 9 equals a 1.8 ERA
9 inning bases RA = 25 divided by 50 equals 0.5, giving you an RA of 0.5 (THIS PART IS WRONG)
What iScore does for the RA is cuts out the part where you have to multiply by 9, or 7 in my case. Unless a pitcher never gives up an unearned run, it's impossible for a pitchers RA to be lower than his ERA. You hear all the time about a pitcher having a great ERA but a bad record because of too many walks or defensive errors. Example: a pitcher could give up 5 runs in 9 innings, but only 1 of them were earned. He might get the loss or no decision but had a great ERA in that particular game.