Expected ERA vs Actual ERA Part II
Thursday
we looked at the pitchers from 2007 who benefited from an ERA which was
better "than deserved". This sabermetric formula is based on a statistic developed by
researchers Dwight Gill and Tad Reeve.
Expected ERA (XERA)
depicts
a pitcher’s "True ERA" based on factors within a
pitcher's control. These factors include Hits, Walks, Home Runs allowed
and K’s. When you consider the inequity with the ERA calculation,
specifically related to errors and base runners inherited/left, many
including myself consider XERA to be a more precise gauge of ability.
The formula as follows: ((.575 * H/9 ) + (.94 * HR/9 ) + (.28 * BB/9 ) -
(.01 * K/9 ) - Normalizing Factor). The normalizing factor is based on the
league (typically in the .270 and .285 range)
Pitchers with a higher ERA (2007) than Expected
Today we're focusing our attention on the Pitchers who posted a
higher ERA than deserved. From this group we're hoping to identify those
pitchers who could be a draft day bargain due to a sometimes
indiscriminate statistic (ERA).
Below is a listing of pitchers who had a higher than
expected ERA in 2007.
Naturally these are also candidates to post better ERA numbers
in 2008.
Chris Young's '08 campaign not only saw him shorted in Wins but
also ERA. Young posted an ERA of 3.12 but according to the xERA formula it
should have been closer to 2.21. Young is a great value heading into '08,
he's #9 on our board in a typical 5x5.
Dustin McGowan is a rising young stud pitcher. His GB ratio of 64%
and .88 K/I % are a great combination. Although his low BHIP% overvalued his
WHIP, his xERA was 87 points less than his actual.
Tim Lincecum was shorted 5 Wins according to our Expected Wins
indicator in '07, additionally his ERA may have been overstated by 67
points.
Wandy Rodriguez
K/I rate has improved, which is improving his runners stranded
rate. Drop in ERA expected as his ERA may have been overstated by 48
points last year.
Barry Zito
Bounceback season projected in both Wins & ERA. xERA in '07 was
48 more than deserved.
Matt Cain xWins pins him at 16 Wins in '07, instead
of 9. xERA shows his ERA expectation should have been over 40 points
lower. Undervalued!
In closing, although our research indicates
that projecting a better ERA based on the XERA formula, is more prevalent
than not. It does not have the same success factor as projecting a
downturn for pitchers who posted a lower ERA than expected (last
week's
article). Since 1992, it's been accurate in about 60% of the cases (63%
last year). Which
is decent but not overwhelming. Again just another tool to increase our
pitching projection accuracy and hopefully your 2008 roster success.
Have a great day!
-Anthony
Comments (2)
Will the XERA be put into the projections for draft purposes?
Posted by Anonymous | March 11, 2008 1:31 PM
Yes, XERA is built into my projections model. All of the pitcher projections include many of the sabermetric indicators that we discuss.
This includes Expected Wins, Balls Hit in Play %, and Runners Stranded Percentage.
Posted by Anthony Perri | March 11, 2008 4:15 PM