Baseball for the Thinking Fan

Login | Register | Feedback

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 eats all pumpkin everything 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


Thanks to
Vegas Watch
for his generous support.


You must be logged in to view your Bookmarks.

Hot Topics

NewsblogTommy Hutton out as Miami Marlins TV analyst after 19 years | Miami Herald
(19 - 8:40pm, Nov 25)
Last: Super Creepy Derek Lowe (GGC)

NewsblogReport: MLB in 'advanced negotiations' to play games in London
(40 - 8:39pm, Nov 25)
Last: Greg K

(774 - 8:39pm, Nov 25)
Last: Orange Julius Is a Synonym for Evil

NewsblogComcast takes shot at Yankees in dispute as cable operator says not many folks watching the games on YES
(1 - 8:27pm, Nov 25)
Last: ReggieThomasLives

NewsblogStarting pitchers should throw fewer innings |
(44 - 8:23pm, Nov 25)
Last: PreservedFish

NewsblogOT: Monthly NBA Thread - November 2015
(1190 - 8:13pm, Nov 25)
Last: Athletic Supporter is trying to remember your name

NewsblogOakland A's acquire Jed Lowrie from Houston Astros for RHP Brendan McCurry
(3 - 8:01pm, Nov 25)
Last: Joyful Calculus Instructor

NewsblogAlex Avila lands with Chicago White Sox
(4 - 7:43pm, Nov 25)
Last: Greg K

NewsblogFree-agent starters Red Sox may try to sign |
(30 - 6:46pm, Nov 25)
Last: PreservedFish

NewsblogOne way to help improve the Red Sox pitching in 2016: Keep Jackie Bradley
(5 - 6:46pm, Nov 25)
Last: tfbg9

NewsblogRed Sox prospect Yoan Moncada is more muscle than man | For The Win
(23 - 6:36pm, Nov 25)
Last: SY Ruined School Lunches!

NewsblogPrimer Dugout (and link of the day) 11-25-2015
(36 - 5:17pm, Nov 25)
Last: just plain joe

NewsblogOffseason plotting for Cubs and White Sox picks up steam at GM meetings - Chicago Tribune
(11 - 5:15pm, Nov 25)
Last: SouthSideRyan

NewsblogMuñoz’s path to the Phillies doesn't often happen
(6 - 4:31pm, Nov 25)
Last: Zach

NewsblogWin a Free Copy of THT 2016! | FanGraphs Baseball
(4 - 3:42pm, Nov 25)
Last: Super Creepy Derek Lowe (GGC)

Page rendered in 0.3096 seconds
47 querie(s) executed