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May 8, 2012

BP Announcements

Rest-of-Season PECOTA Now Available

by Colin Wyers

We are happy to announce that rest-of-season PECOTA projections are now available and will be updated daily going forward.

As a reminder, PECOTA projections are restricted to subscribers. We will not be updating all PECOTA products; right now, updated PECOTAs will be available from:

The methodology is fundamentally the same as it was last year:

We are not rerunning the entire PECOTA process on a daily basis. First off, that would simply be impractical; by the time we got done the next day’s stats would already be waiting for us. Secondly, it would be the wrong tool for the job. Much of the computational horsepower behind PECOTA is spent figuring out how a player will change with age. The effects of age between now and late August are minimal enough to be ignored, and the aging process used to figure a player’s aging between seasons would be very ill-suited to help us capture them anyway.

Instead, we are taking a player’s season-to-date numbers and, in effect, “regressing” them toward the pre-season PECOTA forecast. The weighting is determined by two things: (1) a player’s playing time so far this season and (2) the reliability of a player’s preseason forecast. The more a player plays this season, the more the rest-of-season forecast can move, but at the same time, the forecast for a rookie is more likely to move than that of an established veteran.

We are also doing in-season translation of minor-league stats this season, and those minor-league translations are being incorporated into the rest-of-season projections (albeit with less emphasis than on the major-league stats).

In addition to updating the forecasts with season-to-date stats, we are now baselining the forecasts against the 2012 season to date, so the projections across the board may have moved some as well to reflect the difference between the 2011 offensive environment and the 2012 offensive environment. This will be part of the daily update, so the PFM data will be baselined against current seasonal averages from this point forth.

Colin Wyers is an author of Baseball Prospectus. 
Click here to see Colin's other articles. You can contact Colin by clicking here

9 comments have been left for this article. (Click to hide comments)

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tfierst

Sweet! Great addition!

May 08, 2012 07:03 AM
rating: 0
 
BStephen

And Somehoe PECOTA Still Believes In Nick Markakis :)

May 08, 2012 08:46 AM
rating: 0
 
McLovins

how does it incorporate changes in estimated playing time? Say for example someone like Mike Trout. Let's say before the season Pecota projected 250 AB's for Mike Trout. Is there a change in that estimated playing time now that it looks like it will be more like 500 AB's? Thanks.

May 08, 2012 11:18 AM
rating: 1
 
BP staff member Colin Wyers
BP staff

Rest of season playing time is a function of the depth charts, not the preseason projection for playing time.

May 08, 2012 13:11 PM
 
tfierst

So PFM is now spitting out rest of season numbers?

May 08, 2012 14:08 PM
rating: 0
 
andrewwinters

I just sent an email about this but I was just curious - why do the projections not include games played for hitters?

May 08, 2012 18:58 PM
rating: 0
 
Hoff

Colin is this feeding into the Playoff odds through expected wins column yet? And why not release, like you have before, versions of the playoff odds that variously weight the in season performance. Right now they seem way too heavily influenced by preseason expectations.

May 10, 2012 06:35 AM
rating: 0
 
BBlackwell

Did I read shortly after Pecota's release that player comps were coming to Pecota pages or am I making that up?

May 23, 2012 20:52 PM
rating: 0
 
andrewwinters

The "rest of season" saves projections are out whack. To illustrate, only 10 pitchers in the history of baseball have 50 or more saves in a single season. Yet your rest of season projections as of today (7/4) show 10 pitchers this season who will save 50 or more (Papelbon, Nathan, Johnson, Rodney, Putz, Soriano, Casilla, Kimbrel, Perez, and Hanrahan). You are also predicting two pitchers to actually break the single season saves record of 62 (Johnson and Rodney each with a total of 64 -- 24 on the season so far and 40 more predicted).

Are the saves projections intended to be for the entire year while all the other statistics are for the rest of season?

Jul 04, 2012 07:44 AM
rating: 0
 
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Premium Article Future Shock: Monday M... (05/07)
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BP Announcements: Is s... (03/28)
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