In his book, The Baseball Economist, J.C. Bradbury attempts to find out whether then Atlanta Braves' pitching coach Leo Mazzone really did improve pitchers. He dubbed it The Mazzone Effect, and concluded that Mazzone essentially helped to shave an average of a half run off of each pitcher's ERA.
Last year we saw James Shields lose 0.99 points off of his ERA. Coincidentally 2007 was also Shields' first season under Jim Hickey. At the same time Scott Kazmir saw his ERA rise by 0.24 points and Edwin Jackson's rose 0.31 points. Here's a look at the full progressions and regressions from the Mike Butcher year to the Hickey season by starting pitchers who threw more than 50 innings both seasons or relievers who threw more than 30.
Obviously that's quite suggestive that Shields is an isolated case, or simply an intelligent pitcher coming into his own. While that causes encouragement when you hear that Matt Garza is constantly chattering with Shields during workouts, it provokes a raised brow towards pitching coach Jim Hickey, specifically when Xaiver Hernandez - who is highly perceived as a good coach - sits in AAA Durham.
One, including myself, would argue that the talent he worked with in his first year was hardly the fair to judge him off of, particularly when Hickey is praised for his work in Houston. Which raises the question: did Hickey have any effect on the pitchers there, either positively or negatively?
By assuming that the half of 2004 he spent there didn't do too much good or bad let's see the three year trend for pitchers who fit either the reliever or starter criteria, removing Andy Pettitte and Roger Clemens of course and including Brandon Backe since he fell two innings shy, but more samples were needed.
We aren't truly able to get a feel for just how much of an impact Hickey made on pitchers without digging into the minor leagues, and then you have the question of competition level, defense, and everything else. The one thing we can do however is become optimistic about Hickey, and perhaps Shields, work with Garza. Consider just how closely Garza and Oswalt's pitchf/x cards read.
Obviously mentality and other intangibles come into play, so even that's not a sure thing, but with James Shields helping out other young pitchers and with recorded success with Chad Orvella and Andrew Sonnanstine Garza presumably seeking James Shields out early on is, to say the least, encouraging.