Baseball for the Thinking Fan

Login | Register | Feedback

btf_logo
You are here > Home > Baseball Newsstand > Baseball Primer Newsblog > Discussion
Baseball Primer Newsblog
— The Best News Links from the Baseball Newsstand

Thursday, February 21, 2013

Fangraphs: Larson: Evaluating 2012 Projections

The results of the 2012 forecasting competition.  Composite projections came out the best, but Jared Cross’s Steamer finished first among the independently generated ones.

David Concepcion de la Desviacion Estandar (Dan R) Posted: February 21, 2013 at 04:25 PM | 6 comment(s) Login to Bookmark
  Tags: projections

Reader Comments and Retorts

Go to end of page

Statements posted here are those of our readers and do not represent the BaseballThinkFactory. Names are provided by the poster and are not verified. We ask that posters follow our submission policy. Please report any inappropriate comments.

   1. Danny Posted: February 21, 2013 at 07:35 PM (#4373663)
Yeah, this is a bit like comparing 538/Pollster/RCP to Gallup/PPP/Marist. The former aren't possible without the latter. And I cringed a bit where he said "My personal projections (Larson) took 2nd" given that his "personal projections" are just an averaging of other projections.

Dan, how do you use Pitch F/X in your projections? IIRC, Steamer's use of velocity was credited for its strong pitcher projections the past couple years. Do you use more than velocity?
   2. Walt Davis Posted: February 21, 2013 at 08:51 PM (#4373685)
I assume the target audience for this is traditional 5x5 fantasy players since the projection systems are evaluated using those categories. A title that makes that clear would have been a good idea. If this was meant as a serious evaluation of how well these projection systems predict performance, it's not well done because it's focusing on categories that don't matter much.

I look at two main bases of comparison: the first is the Root Mean Squared Error both with and without bias. Bias is important to consider because it is easily removed from a forecast and it can mask an otherwise good forecasting approach. For example, Marcel projections show very little bias, giving them a low RMSE, but are very poor at predicting variation among players, meaning that it’s not a terribly good forecast if you’re trying to rank expectations of future performance.

Eek! The only "bias" which should be removed is if the projection systems are projecting to different offensive environments (which they often are ... would be good if all the systems just adopted a standard, e.g. the previous year's averages). But if the bias is from other source then it's crucial to retain it in any evaluation. And a low bias method is only problematic for projection if it's lower bias was just random -- if Marcel is consistently lower bias, that's a huge advantage. (I suspect it's not and it is about the different contexts being projected to. Also the author seems to be suggesting that the variance in Marcel is so large that it outweighs the bias advantage -- i.e. it has a large RMSE anyway -- which would be a legit reason it would perform poorly.)

Also please stop averaging ranks as being a useful way to rate things. It assumes that each of the categories is equally important (which in 5x5 fantasy I suppose they are but not in any context that really matters) and that the difference between a rank of 4 vs. 5 (where the actual difference could be tiny) is the same as the difference between 1 and 2 (where the difference might be substantial). Add up the projections to get projected Rbat, Rbase, etc. and go from there.
   3. David Concepcion de la Desviacion Estandar (Dan R) Posted: February 22, 2013 at 02:26 PM (#4374145)
Danny, I made that same point in my comment--my forecasts are probably say 85% intelligent (rather than rote equal-weighted) averaging of other systems, and 15% extra goodies. I do use more than just velocity, yes. Shoot me an email if you're curious about the details.
   4. Der-K is at half whelm. Posted: February 22, 2013 at 04:11 PM (#4374242)
Is this contest judging on a mix of rate and counting stats?
   5. DJS From Suplex City! Posted: February 22, 2013 at 04:45 PM (#4374276)
Yeah, it's 4x4 fantasy evaluations. ZiPS always gets reamed in the ones with counting stats, as I make no attempt to tailor the playing time projections to my prediction of playing time.
   6. AROM Posted: February 22, 2013 at 04:57 PM (#4374291)
ZiPS always gets reamed in the ones with counting stats, as I make no attempt to tailor the playing time projections to my prediction of playing time.


Mine always did too, until I mixed my rate stats with Tango's wisdom of the crowds playing time estimates. I try to answer the question "Who should play" while not caring so much about "how much will he play".

That's worked out OK for me.

You must be Registered and Logged In to post comments.

 

 

<< Back to main

BBTF Partner

Support BBTF

donate

Thanks to
Jim Wisinski
for his generous support.

Bookmarks

You must be logged in to view your Bookmarks.

Hot Topics

NewsblogOT: Soccer March 2015
(825 - 12:06pm, Apr 28)
Last: Juilin Sandar to Conkling Speedwell (Arjun)

NewsblogOTP - April 2015: Church, baseball, politics: Rahm and Chuy work to close the deal
(4256 - 12:05pm, Apr 28)
Last: Greg K

NewsblogPrimer Dugout (and link of the day) 4-28-2015
(12 - 12:05pm, Apr 28)
Last: Der-K is at half whelm.

NewsblogBill Plaschke: Angels drop the ball in dumping Josh Hamilton - LA Times
(9 - 12:04pm, Apr 28)
Last: Bring Me the Head of Alfredo Griffin (Vlad)

NewsblogBrandon McCarthy out for the year with torn UCL
(7 - 12:03pm, Apr 28)
Last: akrasian

NewsblogBBTF 2015 Shooty Memorial Softball Meet-up!
(135 - 12:01pm, Apr 28)
Last: Ray (RDP)

NewsblogOT: Monthly NBA Thread - April 2015
(1773 - 11:57am, Apr 28)
Last: Moses Taylor World Tour 2015: Switzerland

NewsblogBumgarner rejects idea of DH moving to National League, takes offense at Scherzer’s “wet newspaper” comment
(5 - 11:54am, Apr 28)
Last: Russlan is fond of Dillon Gee

NewsblogPitchers batting is dumb and the DH should be universal | HardballTalk
(382 - 11:54am, Apr 28)
Last: JAHV

NewsblogOrioles game postponed amid violence, series could be moved
(69 - 11:52am, Apr 28)
Last: David Nieporent (now, with children)

NewsblogRangers have support system in place to help Josh Hamilton; How it will work | Dallas Morning News
(1 - 11:52am, Apr 28)
Last: Pat Rapper's Delight

NewsblogOT: 2015 NHL Playoff thread
(86 - 11:51am, Apr 28)
Last: JAHV

NewsblogIs it too early to panic about Red Sox rotation? - Sports - The Boston Globe
(16 - 11:50am, Apr 28)
Last: Dale Sams

NewsblogMarlins designate Jarrod Saltalamacchia for assignment
(14 - 11:37am, Apr 28)
Last: Avoid running at all times.-S. Paige

NewsblogBaseball Past and Present: Womack: MLB salaries stayed low longer than people may think
(7 - 11:31am, Apr 28)
Last: ERROR---Jolly Old St. Nick

Page rendered in 0.2226 seconds
48 querie(s) executed