4.40 / (.38 / .5) = 4.4 / .76 = 5.79

4.40 / (.47 / .5) = 4.4 / .94 = 4.68

So it looks like they messed up the starting pitcher replacement level calculation.

]]>The goal here is a proper ordering of players. While these effects may be small, you want a consistent estimator that properly orders players by their effects on run prevention.

]]>Run prevention is divided up between starters, relievers, and defenders, based on their retrospective amount of responsibility. The results of slicing .395 those three ways is .380 for starters and .470 for relievers.

]]>And, that’s actually somewhat besides the point. Regardless of what factors the park actually impacts, the win value of a run changes with the environment. In a park where you only have to score three runs to win, a 5.00 FIP is much less valuable than it is in a park where you have to score six runs to win.

If we were projecting future performance, component park factors would be necessary. For retrospective valuation, it isn’t.

]]>If a ballpark suppresses or inflates offense by x%, why would you adjust the FIP by that same percentage?

If I understand FIP correctly, only one of the variables can be affected by park conditions. Does FIP scale appropriately with park conditions such that you can make this calculation? Or should you do something in the order of “since Safeco Field suppresses offense by x%, you adjust the FIP by x over y% since there are park conditions that do not factor into HR?”

Thanks again for the great work!

]]>