Thursday, February 21, 2008
My approach to player valuationPosted by Derek Carty at 7:59am
I've gotten tons of questions throughout the off-season asking me how I value players for my own fantasy baseball drafts and auctions. By value, I don't mean how I project players, but rather how I decide whether a .300/20/80/80/15 catcher or a 15/3.40/1.15/175 starting pitcher is the better selection. The valuation method I use isn't overly complicated once you understand the concepts, but I believe it is very effective. There are three primary steps:
- Standings Gain Points (SGPs) — Standings Gain Points were developed by Alex Patton in the 1980s. In order to win a fantasy baseball league, you must accumulate more points across a variety of categories than everyone else. That is the goal of every single person playing in a rotisserie-style league. So wouldn't it make sense to value players based on how many points they can gain for you in the various categories? Standings Gain Points do just that.
Standings Gain Points convert a player's contribution in each category into the number of points those stats will allow you to gain in the standings. Adding up a player's contribution in each category gives you his full SGP value.
- Replacement Level Theory — Replacement level theory used for fantasy baseball is very similar to Value Over Replacement Player (VORP), a statistic with practical baseball applications that was developed by Keith Woolner in 2001. Replacement level theory allows us to adjust for position scarcity.
To use replacement level theory for fantasy purposes, you first figure out how many players will be selected at each position. If you're league has 12 owners and starts two catchers, there would be 24 catchers selected. The 24th catcher becomes your replacement level catcher, and his SGP value becomes the baseline for catchers. You subtract this number from every other catcher's SGP value. You repeat the process for each position, and the end result is a list of players spanning every position that are now directly comparable to each other.
- Marginal SGPs — Marginal SGPs were introduced by Art McGee in his excellent book How to Value Players for Rotisserie Baseball. If you're playing in a draft setting (as opposed to an auction), it can be ignored. If you're playing in an auction league, though, this is a very important adjustment.
Raw SGPs don't account for the fact that going into every auction, every owner has (essentially) already spent a portion of his budget. Even if you were to wait until everyone else had filled their rosters, you would still need to spend $1 to fill each roster spot. If you're playing in a 12-team league with 23-man rosters, that's a guaranteed $276 that will be spent.
For that $1, every owner will get, roughly, the exact same SGPs. Even if you don't buy any players for $1, it is still built into the value of every other player. Every player will get you those baseline SGPs, and the good players will then accumulate more on top. Because all owners are equal in this regard, no value is gained from that $1. Marginal SGPs determines the dollar value of players while accounting for this fact.
These ideas are all expanded upon in Art McGee's book How to Value Players for Rotisserie Baseball. If you're interested in seeing the calculations behind each of these steps, I would highly recommend picking it up. I wanted to touch on the ideas here, though, as I'll be referring to some of them leading up to draft day. Now that we have, the next order of business is to talk about my strategy concerning closers. For that, read my next article "Draft Strategy: Closers are overrated."
Derek Carty, 23, has also been published by NBC's Rotoworld, Sports Illustrated, FOX Sports, and USA Today. This season, he'll be contributing to FanDuel and will be linking to all of his work at DerekCarty.com. In his three years competing in expert leagues, he has won 2 titles with 4 top three finishes, including a LABR NL title in 2009, making him the youngest person to ever win a major expert league title. Derek is a proud graduate of the MLB Scouting Bureau's Scout Development Program and is a firm believer in the importance of combining stats and scouting. He welcomes questions via e-mail, Facebook, or Twitter.