| Value Over Replacement Player (VORP) is a | | | | the replacement players statistics should fall below |
| sabermetric statistic made popular Baseball | | | | the real league average. For most positions the |
| Prospectus. Essentially what VORP does is | | | | replacements players statistics are assumed to be |
| compare the value a batter or pitcher contributes | | | | 80% of average. However, for thin positions like |
| to his team verses the contributions of an | | | | the catcher position the replacement players |
| average player at the same position. This average | | | | numbers are further scaled down using a % of |
| player is referred to as the replacement player. | | | | league average factor of 75%. |
| Why is VORP better than using standard | | | | BATTER VORP = Players Runs** - [((Leagues |
| traditional rankings which are based on | | | | Avg Runs / out )* (# of player outs**)) * % of |
| accumulated statistics? When looking at the | | | | league average] |
| Yahoo rating you will miss out on a player that | | | | A simple way to think about VORP for pitchers is |
| has hit a recent hot streak. Furthermore, the | | | | the number of runs that pitcher prevents as |
| VORP calculation takes into account position | | | | opposed to a random pitcher taken off the |
| scarcity as well as home field effects. For | | | | waiver wire. Interesting to note is that rather |
| example, a player with a lot of home runs playing | | | | than use ERA the creators of VORP have |
| in Yankee stadium this year will have a slightly | | | | decided to measure a pitchers contribution by |
| discounted rating since the average player is | | | | how many runs are allowed while he is on the hill |
| hitting an above average amount of home runs at | | | | (Avg Runs) regardless of who is at fault. Another |
| the new Yankee stadium. | | | | thing to note for the PITCHER VORP calculation is |
| Another way of defining VORP for batters is the | | | | that starting pitchers and relief pitchers are |
| number of runs a player contributes vs a | | | | treated differently. This is to account for the fact |
| replacement player off the waiver wire. VORP for | | | | that most relief pitchers will have a significantly |
| batters can be calculated using the formula below. | | | | lower Runs Average than a starting pitcher. Also, |
| Essentially the number of runs a player has | | | | similar to BATTER VORP the calculation of a |
| generated (normalized for ballpark factors) is | | | | pitchers Runs Average per nine innings must be |
| subtracted from how many runs the player would | | | | normalized to account for ballpark effects. |
| have generated if he was an average | | | | VORP = ((Repl. Level - RAvg)/9)*Innings Pitched |
| replacement player. However, in order to allow for | | | | For starting pitchers, Repl. Level = 1.37 * League |
| realistic player to player comparisons it is | | | | RA - 0.66 |
| necessary to normalize a players statistics for | | | | For relief pitchers, Repl. Level = 1.70 * League RA |
| ballpark effects before calculating VORP. | | | | - 2.27 |
| Obviously, it is harder to hit in pitchers parks like | | | | In summary VORP is a useful statistic for |
| San Diego and San Francisco than in hitters | | | | comparing players and can also be used to |
| ballparks such as Coors Field and the new Yankee | | | | evaluate trades. The great thing is that by |
| stadium. The last part of the equation also | | | | normalizing for ballpark effects and position |
| requires clarification. After calculating how many | | | | scarcity the metric is a good measurement to |
| runs would be generated by the average | | | | compare players across multiple positions. To find |
| replacement player, the number is scaled by a | | | | out more about VORP as well up to date player |
| factor called % of league average. Since the level | | | | VORP calculations check out the Baseball |
| of talent in the major leagues is far from a | | | | Prospectus. |
| normal distribution, the assumption is made that | | | | |