Here’s Where the Projections Disagree

Good news! It looks like we have our ZiPS information uploaded. What that actually means — until now, whenever you looked at the projected standings, you were seeing Steamer projections, only. Now you should be seeing 50/50 Steamer and ZiPS projections. This is the way we’ve done it for a while, evenly compromising between the two systems.

So, first, here’s the current projected winning-percentage landscape, displayed poorly and with an arbitrarily-truncated y-axis.

I can’t imagine there’s too much that takes you by surprise. Cubs good. Padres bad. Dodgers good. Brewers bad. We have some understanding of pretty much everyone, and forecasting systems never disagree that dramatically.

But they can and do disagree! So we can quickly look at that. What we have right now are blended projections. What we had at the end of last week were the Steamer projections. It requires only some simple math to isolate the ZiPS projections, and from there, we can look at the differences between what ZiPS says and what Steamer says. In this plot, I’ve subtracted Steamer win% from ZiPS win%. The teams on the left are favored by ZiPS. The teams on the right are favored by Steamer.

I’ve done nothing here to examine the Why. That would be something for a larger article. But, Blue Jays fans might’ve noticed a bump in the projected standings today. That’s because ZiPS likes them about five wins better than Steamer does. Ditto the Orioles and, partially, the Mets. You also see the Cubs get a bump, with Steamer being a little higher on the Dodgers. But Steamer has the biggest positive disagreement in the directions of both the Royals and Yankees, who Steamer likes more by four and a half wins. Interesting! Again, I’ve done no further research. This whole thing took 10 minutes from start to finish.

This doesn’t mean ZiPS is more right, nor does it mean Steamer is more right. There’s a reason we fold them both in with equal weights. This is just to help explain why you might’ve seen some shifts in the standings. ZiPS has got opinions, see. It’s not just Steamer re-packaged.





Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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arun7989
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arun7989

I wonder if ZIPS weights for team presidents. Randy Levine should be worth roughly negative 4.5 wins.