xERA different numbers

[adichiara]

On the player profile pages xERA is referenced but it is not the same number that comes up in the file. I have the 2003 pitching file open now and I noticed is is significantly different than the xERA that are referenced on the site. For example, on the site is says Eaton's 2003 xERA is 3.62, but in the file it says it was 3.90. This is for every player on, I assume, every year.

Like I just looked at Nate Robertson's xERA from 2004, on his player database page it is refered to that he had a 4.91 ERA (which is correct) and a 3.52 xERA while it states his xERA was 4.87 on the 2004 player file.

What's with this difference, its extremely hard to use the files as a reference when none of the stats are the same.

[OttotheSwatto]

xERA Playerlink monthly splits vs yearend

Another xERA variance is in regard to 2006 yearend vs monthly splits.
In trying to make a decision regarding Paul Maholm, I see his 2006 yearend xERA is 5.18.
However all of his 2006 monthly splits are below this number- most significantly
apr 4.53 may 3.62 june 3.82 july 3.63 aug 3.73 sept 3.27

This doesn't seem to make mathematical sense
Have I missed an explanation regarding these numbers.

Otto

[RAY@HQ]

adichiara - not sure this is the issue in your case, but the xERA formula has evolved quite a bit over the last few years. The 2004 xERA formula was very different than the one we're using now. And I'm not sure we go back and change the 2004 year-end file to reflect the 2006 formula... you can imagine how that could easily turn into a continuous loop. Again, not sure that's the issue, but just reading your msg that's the first thing that comes to mind.

Otto - Maholm's YTD xERA was/is 3.78. The 5.18 is the projected xERA, which is meaningless at this point (since he's got 0 projected innings).

[Lefty]

Ray, you lost me a bit. Shouldn't the season end projected xERA, exactly because it has no projected innings, equal the actual xERA. Sounds like a fluke/flaw in the projection model.

[OttotheSwatto]

Thanks Ray for the quick reply.
I was thrown off a bit as I was looking at the bottom line of the yearly stats as the final stats. I can see now where the correct yearend xERA is(and Maholm is looking much better than I initially thought!). As Lefty says however it is a bit confusing.
thanks again,
Otto

[RAY@HQ]

Yes, all the projected numbers should be zeroed out at this point. But they'll be back soon enough when we post 2007 projections!