wOBA to WAR Conversion Spreadsheet

Update 2 11/10/09 - 4:20 MST - In column B of the spreadsheet there was some extra calculations that added 2 extra runs to all calculations.  I think they were an artifact from once wanting to add WAA.  They have been removed and the spreadsheet is corrected.

Update 11/10/09 - 4:00 MST - An error was found in the spreadsheet.  I will post a corrected version later tonight once I get a chance to make the correction.  Sorry for this inconvenience. -Jeff

Last Friday, Justin ran an article on free agent first basemen with their 2009 wOBAs. Justin and I determined that it needed a baseline wOBA for reference. The overall league averages can't be used because each position has its own run adjustment depending on its difficultly. For example, 2B is much harder to play than 1B, so if Chase Utley and Ryan Howard have the same wOBA, Chase's value is worth more since he is playing a more difficult position. Fangraphs has a great explanation of the process for each value in the WAR calculation.

I created a spreadsheet that has the projected RAA, RAR and WAR for each position assuming a certain wOBA.  

For the spreadsheet I made the following assumptions:

  1. The player plays an entire season thereby getting the entire positional adjustment and has 700 plate appearances
  2. Player is a league average defender. If defense is needed, use a multi-year average of UZR from Fangraphs. 
  3. The values for "League Average wOBA," "conversion of wOBA to runs, PA per year," "Run to Wins Conversion" and positional adjustments are set to the current league scoring conditions.  The spreadsheet can be downloaded and these values can be manipulated as each user sees fit.
  4. No assumptions are made for league adjustments (AL being more difficult than NL) in the calculations.

Here are the wOBA values for each position needed to get league average and replacement level production:


Average Level Replacement Level
All Players 0.327 0.289
C 0.310 0.273
SS 0.32 0.28
2B/3B/CF 0.326 0.289
RF/LF 0.342 0.305
1B 0.350 0.313
DH 0.366 0.329

Examples for using the spreadsheet.

Example 1. Justin's look at 1B Free Agents

Here is the graphic Justin posted Friday:

Faf2010-1b-woba_medium

Values are in the graphic, but no reference for meaning. Instead, if we look at the preceding table, we can see that a 1B needs to hit .350 for league average production. There are only 5 free agent first basemen that meet this criteria (LaRoche, Mientkiewicz, Branyan, Johnson, and Delgado). Also we can find that 6 players contribute at below replacement level when batting (Garciaparra, Cairo, Millar, Tracy, Betemit and Aurilia).

Example 2 - The Royals are considering having Jose Guillen be the permanent DH next season. What does his wOBA need to be to contribute positive WAR for the Royals?

This answer is actually pretty simple. He needs to bat a wOBA of 0.329 since there is no defensive adjustment to add. Currently, Bill James, the only person out with projected wOBA, has Jose projected to hit a wOBA of 0.321. Jose's production isn't enough to get DH replacement level production.  Then by going back to the spreadsheet, it can be seen that if he gets 700 at bats he will have a -0.5 WAR.  The Royals should be looking for another DH if they are hoping to have at least replacement level contribution from the DH spot.

I hope that you find this spreadsheet useful, and let me know if you need any further explanation.

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