I'm curious as to how people arrive at their forecasts, and hopefully you guys are some approximation of a representative sample. As far as I can tell, there are two ways:
(A) Project what you consider to be the most likely season
(B) Project what you consider to be the weighted average of all possible seasons
0 recs | 37 comments
Without enough mathematics knowledge
Nor, really, the interest in spending large amounts of time on my projections, I pick what seems to me to be the most likely season (which may really be my internal weighting of several possibilities). I sort of treat the whole exercise as “reach into a hat with X number of seasons (with the more likely seasons being represented more often) on it, and pull out one,” then submit what I “pull out (of my ass, obviously)”
Sportszilla - December 2, 2009
I really wonder what Tony Blengino's predictions look like.
I just guessed. I really didn’t put a great deal of thought into mine, because I am really bad at math.
mark sobba - December 2, 2009
I tend to do some averaging, with emphasis on seasons that just occured.
I usually find myself to be a little harsh on players, usually not projecting growth. I’d rather have them exceed my expectations. Probably negates my math a bit.
MT Olson - December 2, 2009
I'm pretty sure these predictions
better reflect the “median” production than the average production. Most of the error is probably associated with not factoring injuries and the possibility of massive collapse which cause people to overpredict playing time which inflates player value. Otherwise I bet they are probably pretty reasonable. I’d hope the rate stats are accurate at least.
Edgar for Pres - December 2, 2009
I wouldn't classify that so much as error as I would viewing the purpose of the projections in different ways.
Aaron Campeau - December 2, 2009
Maybe I am misunderstanding this but I don't see how you can do A without B
Poochie - December 2, 2009
A gives no consideration to unlikely events like catastrophic injury or rapid decline
Jeff Sullivan - December 2, 2009
Unless it's Bedard
Jeff Sullivan - December 2, 2009
It is not prudent to project unlikely things
Poochie - December 2, 2009
I project what I think the ~50th percentile will look like, which I would see as the most likely outcome.
That is also, in a way, the weighted average no?
abender20 - December 2, 2009
Unless your prediction curve is asymmetric, I suppose.
abender20 - December 2, 2009
I think pretty much all prediction curves ought to be asymmetric
It’s a lot easier to be more bad than more good.
Jeff Sullivan - December 2, 2009
Yes
None of these should be bell curves
Graham MacAree - December 2, 2009
Unless you're replacement level
vivaelpujols - December 2, 2009
Disagree
Curve is going to be skewed in favour of positive WAR for replacement level players, I think. Just because if they do badly they’re going to get pulled fast.
Graham MacAree - December 2, 2009
You're right
I was more responding to Jeff’s statement above.
vivaelpujols - December 2, 2009
I don't have a good feel for that, I guess.
For Franklin, I’d put his 90th percentile wOBA at something like .375 and his 10th at .295 or something and so I’d tell you ~.335 as a most likely. Not a bell curve, but probably still something like a 5/4/3 hovering around .335 and the rest can go to hell. To me, the asymmetry lies in the tails and it’s enough of an abstraction anyway that I don’t worry about it.
abender20 - December 2, 2009
I'm not very math savvy so I try to stay conservative and input numbers that don't look ridiculous (one way or the other)
Poochie - December 2, 2009
I think about the range and likelihood of outcomes, but that basically just does what you do.
abender20 - December 2, 2009
I don't do these projections because I routinely predict a player's 0.000001%th percentile and assume they'll spontaneously combust in the batter's box
Graham MacAree - December 2, 2009
Only Delmon Young has managed to do this.
abender20 - December 2, 2009
I love how Utley is being projected by the fans to have the highest WAR
I think if you are looking for fan bias, there it sits
Poochie - December 2, 2009
I'm confused
You don’t think Utley will have the highest, or close to the highest WAR, or are you being sarcastic.
vivaelpujols - December 2, 2009
No I think it will be unlikely that he will be better than Pujols or a few others
I just think he’s “the guy” for people of the Fangraphs and it is leaking into the projections
Poochie - December 2, 2009
It's probably compensation for the jackass BBWAA
You know, like the reason everyone hates Jeter.
vivaelpujols - December 2, 2009
Pujols WAR is going to take a small hit
Due to league factors when the Cards trade him to the AL next year as the team is going down in flames.
CMC_Stags - December 2, 2009
Pujols'
CMC_Stags - December 2, 2009
I don't know why you would project that
Poochie - December 2, 2009
I think that doing a weighted average would be the best way to go
But I wouldn’t want to go through all of that work to get something marginally better than the median projection.
Anyway, I love that FanGraphs displays the WAR projections at the bottom of the page – makes things a lot easier.
vivaelpujols - December 2, 2009
Maybe it would be easier
to suggest people predict most likely outcomes. Then have a few questions to build an idea of how to correct for the range of distributions. A simple system might be good enough such as:
How likely is the player to be on the 15 day DL?
How likely is the player to be on the 60 day DL?
How likely is the player to be at least 25% worse than what you project?
How likely is the player to be at least 25% better than what you project?
Just off the top of my head, it might be easier for people to project this way. It would also make sure we can account for everything correctly.
Edgar for Pres - December 2, 2009
The whole idea of projecting is to project the most likely outcome
Poochie - December 2, 2009
No its to project the average outcome
Edgar for Pres - December 2, 2009
Ok it depends what you are trying to project
If you are trying to predict team wins then you do average.
If you are trying to predict player value you use average.
If you want to guess the player’s performance you use most likely.
Edgar for Pres - December 2, 2009
I like that you used "predict" for the things that mirror your view of the purpose of these projections
and “guess” for the thing that doesn’t.
Aaron Campeau - December 2, 2009
I really couldn't come up with a reason you wanted to use the average outcome
The only thing I could imagine would be if you were around with your friends trying to predict/guess how many HR a player would have.
I guess it was an unintentional slip. I admit not the most professional rebuttal.
Edgar for Pres - December 2, 2009
Fan projections are not PECOTA
Poochie - December 2, 2009
Accidentally voted for B, but yeah, A.
gregrabble - December 2, 2009
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