Note: The following
was retrieved from the Internet
Archive Wayback Machine after it disappeared from its previous home
at http://www.baseballstuff.com/mccracken/dipsexpl.html.
It's Voros McCracken's work, not mine, but he has granted me permission
to display it here to keep it in circulation. — Jay Jaffe |

This is the full explanation on how to calculate the new version of DIPS.

- You will need the following stats:
- Batters Faced (BFP) - If you don't have it, it can be estimated by BFP=(((IP*3)-SO)*.966)+Hits+Walks+Strikeouts.
- Home Runs Allowed (HR)
- Total Walks Allowed (BB)
- Intentional Walks Allowed (IBB)
- Strikeouts (SO)
- Hit Batsmen (HP)

- You will also need the following information:
- Whether the pitcher is a Knuckleball pitcher
- What hand the pitcher throws with.

- You will probably want to park-adjust the above stats however you want to do so. There are many different theories on the best way to do this. It is important that this is done before the following calculations are done. Otherwise things will get screwed up.
- First Step is to multiply BFP by .0074. This will give you the DIPS number of intentional walks allowed (dIBB).
- Next, divide HP by BFP-IBB. Call this $HP. Then multiply $HP by BFP-dIBB. This number gives you the DIPS number of Hit Batsmen (dHP).
- Divide BB-IBB by BFP-IBB-HP, and call this number $BB. Then multiply $BB by BFP-dIBB-dHP. Take this number and add dIBB. This number is now the DIPS number of total walks allowed (dBB).
- Divide SO by BFP-HP-BB and call this number $SO.
*Remember this number for later*. Multiply $SO by BFP-dBB-dHP. This will give you the DIPS number of strikeouts (dSO). - Divide HR by BFP-HP-BB-SO and call this number $HR.
*Remember this number for later*. Multiply $HR by BFP-dBB-dHP-dSO. This will give you the DIPS number of Home Runs (dHR). - Now we'll estimate hite per balls in play ($H):
- Take the number .304396 and subtract .01083
*if*the pitcher is strictly a Knuckleball pitcher. If not keep the .304396 number. - Take the result from the last step and add .002321 if the pitcher is left handed, if not keep the number from the above step.
- Take the $SO figure from way above and multiply it by .04782. Subtract this number from the number from the last step.
- Take the $HR figure from way above and multiply it by .08095. Subtract this number from the number from the last step. Whatever number you now have is your $H figure.

- Take the number .304396 and subtract .01083
- Multiply $H by BFP-dHR-dBB-dSO-dHP. Add this number to dHR. This number is the DIPS total of Hits Allowed (dH).
- Take BFP-dBB-dHP-dSO-dH and multiply that number by 1.048. Add dSO to that number. Take that number and divide by 3. This is the DIPS total of Innings Pitched (dIP).
- Sum the following products: (dH-dHR)*.49674; dHR*1.294375; (dBB-dIBB)*.3325; dIBB*.0864336; dSO*(-.084691); dHP*.3077; (BFP-dHP-dBB-dSO-dH)*(-.082927). The sum of all of these is the DIPS total of earned runs (dER).
- Calculate ERA as you normally would. (dER*9)/dIP. This is the DIPS ERA (dERA).
- From here you can use the numbers as you see fit. Treat them as you would "normal" pitching stats.

I hope this was helpful. If any of this was unclear, please e-mail me and I will help you out.

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voros@baseballprimer.com

January 17, 2002