Looking at baseball projection systems

ZiPS projections for the 2010 season can be found, free of charge, here .

Sample prediction: According to ZiPS, Prince Fielder, who drove in a career-high 141 runs last year, will drive in 142 this season.

PECOTA

This is Baseball Prospectus' proprietary engine (subscription required), and the man behind the curtain is Nate Silver of Fivethirtyeight.com, the Web site that analyzes polling and political data. PECOTA (Player Empirical Comparison and Optimization Test Algorithm), like most other systems, forecasts production and playing time by using a player's performance history and by examining players deemed to be similar. Also, PECOTA uses what's called "phenotypic attributes," a category that includes things like a player's height and weight. PECOTA takes all these data and the resulting player forecasts and also makes predictions on the team level.

Sample prediction: PECOTA says the playoff teams in 2010 will be the Phillies, Cardinals, Rockies, Braves, Red Sox, Rangers and Yankees. Why just seven teams? PECOTA foresees a three-way tie for first in the AL Central ...

Marcel

Tom Tango's Marcel system is as simple as these things get. It's so named (after the monkey on "Friends") because it requires nothing more than a monkey's grasp of the system (not quite true, but the point is made). Tango describes this system thusly: "It uses three years of MLB data, with the most recent data weighted heavier. It regresses towards the mean. And it has an age factor." You can download the Marcel spreadsheet for 2010 here .

Sample prediction: Marcel tabs David Wright for 19 home runs in 2010.

Bill James

The master of the statistical movement is still cranking out projections. Actually, he's doing hitter projections (based on past performance, age, home park, and expected playing time), and Baseball Info Solutions (BIS) is doing pitcher projections on James' behalf. To arrive at their numbers, BIS uses eight years of data (when possible, of course) with a particular focus on the last three. As well, they project innings based on how the pitcher was being deployed late in the most recent season. You can find the Bill James projections at Fangraphs.com.

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