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Why Picking Your Projection System Matters
Posted By Chad Young On January 8, 2013 @ 8:15 am In Projections,Uncategorized | 28 Comments
Prior to each baseball season, usually in January or February, I put together a massive spreadsheet that rates players in every format I play in. Placing a value on a given player is actually not that hard, assuming you have a decent projection of what that player will do over the course of the next season. Valuing “Albert Pujols” may not always be easy, but if I tell you I have a 1B who will put up 31 HR with a .285/.359/.516 line, that is something you can probably work with.
The issue is that depending on what system you pick, you could end up with some very different values.
Just as an example, I picked five players at random from the ZiPS projections released to date and compared their total points in an ottoneu league in three different projection systems: ZiPS, CAIRO, and Bill James Projections. A table of the results are below:
A couple things should jump out at you. First, the Bill James projections are roughly 150 points higher, on average, than the other two, and this is despite being LOWER for Aybar. James projects more than 300 more points from Pujols than does ZiPS. Last year, 319.5 fewer points would have moved me from 1st to 3rd in the FanGraphs Staff League.
Next, ZiPS and CAIRO are within 78 points of each other for all five players, and within 50 points of each other for three of the five. James is only within 50 points of the other two in one case – a 31.5 point gap between James and CAIRO on Aybar.
The fact is, if you are using Bill James Projections as your primary method of valuing players, you are likely expecting bigger numbers from your players than other owners. Those projections have one player over 1300 pts (Miguel Cabrera), three more over 1200 (Pujols, Mike Trout, Prince Fielder), and 13 more over 1000. CAIRO, by contrast, has no one even over 1200 and only six players (Cabrera, Joey Votto, Trout, Ryan Braun, Fielder, and robinson Cano) over 1000. That’s a big difference.
And it isn’t just hitters. Nineteen starting pitchers are projected to crack 1000 pts by the Bill James Projections; CAIRO has only 11. As a result, a pitcher who posts 200 IP, 200 H, 20 HR, 50 BB, 5 HBP, and 200 K, thereby scoring 949 points, would be the 19th ranked pitcher in CAIRO’s world and the 31st ranked pitcher in Bill James’s.
So, there are a couple things to keep in mind and a suggestion:
1) When you are talking to another owner and saying you expect 35 HR or 1,000 pts or whatever out of a given hitter, and he only projects 25 HR or 800 points, keep in mind the difference may have more to do with a projection system than anything else. One of you may be using ZiPS while the other uses Bill James.
2) Even if you agree on the stats, that does’t mean you agree on value. As with the 200 IP SP described above, one of you could be talking about a top-20 starter while the other is looking at a mid-tier guy.
And the suggestion:
Use multiple systems. I take the time each year to put together a mixed projection using a number of systems, but if you aren’t going to do that (and I don’t blame you for not wanting to do that), I recommend looking at multiple projection systems and building your own opinions based not simply on believing that ZiPS or CAIRO or James or anyone else is best, but on recognizing that each system will have its strengths and its flaws.
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