Behind the numbers (cont.)
Posted: Monday February 19, 2007 3:40PM; Updated: Monday February 19, 2007 3:43PM
It's worth noting that ZiPS does not attempt to project playing time and of the four projection systems, it has the most players with 995 batters and 989 pitchers, many of whom have yet to play in the majors. So with at least a decent idea of the workings behind each projection system and their differences, let's take a look at how similar they are by comparing how they project OPS and ERA for individual players. Using the Marcels as a baseline since it's the simplest system of the four, if we look at batters with at least 300 at-bats in projected playing time, and pitchers with at least 100 innings in projected playing time, we'll see that the four systems are quite similar.
Despite their similarities as a whole, there are a number of differences in the four systems if you look at any specific players. Here are the 10 batters the systems are in the least agreement with in terms of OPS:
It's interesting to see Ryan Howard atop the list. Everyone expects him to be very good, but there's certainly some question about how great he'll actually be. At least CHONE and ZiPS seem to think Carlos Delgado is in for a rather steep decline next year, while the other two think he'll keep chugging along at his .900+ OPS.
But the problem with comparing OPS across projection systems, especially for the fantasy baseball players out there, is that it that it takes the systems out of their own context, which is why it might be more helpful to rank the players by OPS and see how their rankings compare. Once again, here are the 10 players the systems are in disagreement about in terms of ranking by OPS.
A few of the same names show up on this list like Dan Uggla, Andre Ethier, Luis Gonzalez, Esteban German, and Chris Duncan, but you'll notice it devoid of Howard. Despite the systems not agreeing on his actual OPS, they all agree that he'll have one of the top OPSes in all of baseball:
Moving on to the pitchers and their projected ERA, you'll remember that overall there was a bit more disagreement between the systems for pitchers and ERA than there was with batters and OPS. Pitchers are quite a bit more unpredictable than batters. So let's see where the systems are in disagreement:
A few names stand out to me here, mainly Rich Hill and Curt Schilling. The Handbook takes the low road on both of them, with the Marcels not being quite so optimistic. With only one year of major-league playing time for Hill, there's going to be some heavy regression for the Marcel projection. The Handbook is also quite smitten with Clay Hensley. I can only image it has something to do with him playing in PETCO park and his extreme groundball tendencies. Let's take a look at where the projections are in agreement:
It's interesting to see such agreement on Bronson Arroyo considering he's had exactly one year with an ERA under 4.00. Obviously, C.C. Sabathia and Carlos Zambrano have had a much better long-term track record and it shows in both their projected ERA. It's also fun to see that everyone agrees Kirk Saarloos and Gil Meche are nothing to write home about. But where are Johan Santana and Roger Clemens? Let's take a look at one last list that shows which player each projection system is in agreement on in terms of ranking by ERA:
So whatever projection system you're inclined to use, regardless if it's actually better or worse than either of these four, it's probably similar as a whole yet with its own nuances. A second opinion never hurts, and if you head over to FanGraphs, you'll find four other opinions at your disposal.