With the ZIPS projections now loaded onto the site and the player pages, I thought it’d be fun to take a look at a few examples where ZIPS and Steamer — probably my two preferred projection systems at the moment — differ this year, and whether there’s anything in particular we can learn from those differences.
First, I wanted to whittle down the population of players that I was dealing with. While I appreciate Steamer’s pluckiness, 4,136 projections for position players might be a little bit of overkill. I, for one, am not overly concerned with how Jeyckol De Leon is going to perform this year. Maybe it’s just me.
ZIPS projects a slightly more sane number of position players — 1,046, to be exact — but even that is still a little unwieldy, as a good chunk of those guys are sub-replacement level minor leaguers who aren’t going to see the Majors this year. By and large, we care mostly about the projections for players who are going to see substantial regular playing time in the big leagues this year, or at least, I do. Carson can care about all the fringe prospects he wants; I’ll leave that to him.
So, in order to get a list of projections for guys we care about, I excluded players who had never been in the majors or were projected to be below replacement level, leaving us with 601 Major League position players. That was still a little unwieldy, though, so I took the top 180 players by the average WAR of the two systems, which gave us a good selection of players that are projected to be league average or better by one of the two systems.
From there, it was a pretty simple sorting task to find some big differences, but many of them are driven by assumptions about playing time rather than big gaps in the actual projections. For instance, ZIPS lists Brett Jackson as a +2.5 WAR player, while Steamer comes in at just +0.9, which seems like a huge difference of opinion until you realize that the ZIPS number is based on 626 PA and the Steamer number is based on 274 PA. Rescale them both to 600 PA, and the gap is just 2.4/2.0, showing that the two systems are essentially in agreement on Jackson’s overall profile for 2013.
Since I care more about the differences in the projected performances than in the playing time gaps, we’ll focus on the big discrepancies in projections per 600 plate appearances (or 450 PA for catchers). Putting things on the same playing time scale will inflate the numbers of part-time players and injured guys while depressing the numbers of durable iron men, but we’ve already gotten rid of most of the part-time guys with our filtering, so that’s a trade-off I’m willing to make. Oh, and thankfully, the two systems were already on almost identical scales for these players, so there was no need to make any adjustments to the numbers as we did with the Fans projections last week.
Long introduction finished… on to the differences. We’ll start with the 14 players where Steamer projects at least +1 additional WAR per full season (600 PA non-catchers, 450 PA catchers):
Read the rest of this entry »