Frank Delicious wrote:also on a Projections note, I looked up Longoria's stats on Fangraphs and see that James is the only one predicting him to get over 100 RBIs, over 30 homers and has really upped his SLG and ISO (although his projection is close to Evan's 08 season). Do you think James is overvaluing Longoria's power or Chone and others are undervaluing it? I kinda see James view here and think Longoria is going to improve or at least maintain last year's power levels.
A good projection system will more often than not seem to undervalue a fair amount of players, particularly young ones without a lot of major league time, because they're really projecting a range of outcomes of which the one line they give you is the mean. The problem with James' projections in the past, I don't know if he has changed the system at all recently, is that they tend to overall be pretty optimistic. They tend to reflect a positive scenario for the upcoming season for most players when the reality is that some players will break out or have flukish good years while others will regress or decline. A projection system's goal isn't really to get an individual player right, it's to get all of MLB fairly accurately in aggregate. In Longoria's case CHONE, Marcel (a projection system which basically just weights the last three years of a player's performance to make the projection and tends to be at least close to the much more complex systems in accuracy), and ZiPS all have him roughly repeating last year in BA/OBP/SLG so James is simply betting on his power taking a jump while the other systems are more conservative about it. My favorite example of the way projection systems should be looked at, it really illustrates how they tend to work: http://www.battersbox.ca/article.php?st ... 5035119999
It's interesting that neither PECOTA or Marcel predicts anyone will hit 40 home runs this season.
It just seems that PECOTA is too conservative across the board - almost too much regression.
Marcel's also got Teixiera at 29 HRs. And, Marcel's regression towards the mean is exactly perfect.
Look at all the guys forecasted for 28 to 30 HRs: Beltre, Sheffield, Delgado, Teixeira, Andruw, Soriano, Tejada, HElton, Berkman, Konerko, Palmeiro, Burnitz, Beltran.
Half of those guys will hit more than 29 HR, and half will hit less. But, you, me, and everyone else has no idea who will hit 30 or 35 HR. Bad luck, good luck, injuries, whatever... everything plays a role in this.
Marcel's best guess is that those 13 hitters will average 29 HRs.
If you wanted Marcel to forecast number of HR without attaching names to it, that'd be alot easier, and the range would be wider.
Think of these forecasts as over/unders.
Look at my comments, 3 posts (and 1 year) earlier. Ok, so I decided to find out what those 13 guys I listed did. Here they are:
6 guys with more than 30, and 7 less than 28. Average? 29.5.
For this on the fence on forecasting systems, I hope this little exercise makes it clearer.
People were complaining that PECOTA and Marcel were too conservative because they didn't project enough home runs for the big power guys. In the end the systems were "wrong" about most of the guys, they hit a lot more or a lot fewer home runs than projected, but overall it was actually an accurate estimate. Longoria may well have that power jump James predicts but chances are good that someone else that James predicts for a power jump that the other systems were conservative on too will fall off some this season.