Optimistic Projections.

UPDATE: The table in the article has been updated with actual 2011 wOBAs for each player, along with actual 2011 PAs. An aggregate line has been added with the combined projected and actual wOBAs weighted by actual 2011 PAs. Also, in light of Mike's response below regarding the handling of intentional walks in their projections, it is possible the RotoChamp wOBA values are artifically-inflated, so the difference between the average Roto projection and the actual might not be meaningful.

While looking through the projections posted at FanGraphs, I noticed that some of the RotoChamp projections seem a bit optimistic. For example, Jim Thome is projected with a .419 wOBA. Thome had a good year last year, putting up a .437 wOBA over 340 PA, but he's also 40 years old, and even with a potential HOF career behind him, his career wOBA is only .407.

This looks like a simple case of under-regressing 2010 performance and not enough weight given to past performance. However, other optimistic projections fall out of this pattern. For example, Albert Pujols is projected with a .449 wOBA, higher even than his career .434 mark despite Albert now being on the wrong side of 30 (it appears the wOBA projections may not remove IBB, so Albert's career wOBA with his IBBs counted as nIBBs would be .444; closer to his projection, but still lower). Albert's 2010 performance, however, does not seem to be driving the high projection; he hit only .420 last year.

Does RotoChamp see something important in projections like these, or is the optimism misplaced? I find 20 different players listed in both the Marcel and RotoChamp projections who are projected at least .030 points wOBA higher by RotoChamp than Marcel. They are:

Name Age Rel Marcel RotoChamp diff 2011 PA
2011 wOBA
Jim Thome 41 0.81 0.360 0.419 0.059 324 0.362
Dan Johnson 32 0.4 0.327 0.381 0.054 91 0.181
Jose Bautista 31 0.84 0.362 0.408 0.046 655 0.441
Brandon Allen 25 0.38 0.321 0.367 0.046 195 0.286
Ramon Castro 35 0.6 0.319 0.361 0.042 75 0.332
Magglio Ordonez 37 0.83 0.345 0.386 0.041 357 0.283
Ryan Hanigan 31 0.69 0.329 0.370 0.041 304 0.320
Chipper Jones 39 0.83 0.353 0.393 0.04 512 0.345
Jorge Posada 40 0.79 0.341 0.381 0.04 387 0.309
Matt Diaz 33 0.74 0.330 0.367 0.037 268 0.280
Andruw Jones 34 0.75 0.323 0.360 0.037 222 0.371
Albert Pujols 31 0.87 0.414 0.449 0.035 651 0.385
David Ortiz 36 0.85 0.347 0.382 0.035 605 0.405
Jason Giambi 40 0.78 0.326 0.359 0.033 152 0.407
Matt Treanor 35 0.64 0.279 0.312 0.033 242 0.291
Miguel Cabrera 28 0.87 0.390 0.422 0.032 688 0.436
Chase Utley 33 0.86 0.370 0.401 0.031 454 0.344
Aubrey Huff 35 0.87 0.345 0.376 0.031 579 0.294
Jed Lowrie 27 0.65 0.336 0.367 0.031 341 0.297
Manny Ramirez 39 0.81 0.371 0.401 0.03 17 0.052






TOTAL PA

weighted average
0.354 0.392
7119 0.353

This does not include prospects who have not appeared in the Majors, such as Brandon Belt, who RotoChamp likes a lot (.385 projected wOBA). Technically, Marcel projects these players with a league average wOBA, so they could be included, but whether or not RotoChamp's prospect insights add value is a separate issue than what I am looking at here. Other than Brandon Allen, these players all have fairly established Major League track records with plenty of data for a projection system to work with, and RotoChamp is still seeing them very differently from Marcel.

The test here is simple. At the end of the year, will Marcel's or RotoChamp's estimates for these 20 players be better? Additionally, will this group signicantly outperform its Marcel projections, even if they still end up closer to Marcel than RotoChamp? After all, RotoChamp could be finding something that Marcel is underselling in these players and still be over-weighting that insight to end up with overly optimistic projections.

Most of the players on the list are in their 30s or 40s (all except Miguel Cabrera, Jed Lowrie, and Brandon Allen). Their average age is 34. Many, like Thome, Jose Bautista, and Andruw Jones are coming off big 2010 seasons, while some, like Albert and Manny Ramirez, are big names projected for bigger numbers than their 2010s would indicate.

1 comments:

spydog said...

Thanks for doing analysis on our projections (RotoChamp). We didn't provide FanGraphs with IBB or wOBA data, so the wOBA projections on their site might not be accurate. I'm not sure how they are calculating wOBA for us.

I would throw out any comparison for guys like Dan Johnson who have low reliability scores in Marcel.

This is our first year doing projections and we may or may not be regressing for age enough.

Magglio is an interesting case. His xBA (by our calcs) was .335 last year versus a .303 actual BA. Since we ignore BA in our projections and use xBA, we will be more optimistic for him than other systems.

I haven't looked at everybody, but I know Bautista and Dan Johnson have both been 'unlucky', and that is why they will be seen more optimistically in RotoChamp than other systems.

Marcel will probably beat our system if you look at cumulative stats over the entire pool, but our system should be stronger in providing relative value for fantasy purposes. This is because our projections are optimistic across the board in terms of projected ABs and IPs.

Thanks,
Mike - RotoChamp

Post a Comment

Note: Only a member of this blog may post a comment.