Question: is there a particular number that is most useful in evaluating fantasy WR prospects?
Argument: Three-year season yardage total (or average)
Elite Wide Receivers are so wonderful in fantasy football because they are so reliable. WRs are much less injury-prone than RBs, and the elite WRs are much less prone to great swings in their statistics from year to year. Look at the career numbers of players like Jerry Rice, Cris Carter, Tim Brown, Marvin Harrison, or Torry Holt, or Chad Ochocinco. Look at the career numbers of current WRs still playing at a high level, like Randy Moss, Larry Fitzgerald, or Reggie Wayne. When you look at these players, you see a whole string of seasons with high production in yardage and touchdowns.
Of course that doesn't mean those elite WRs can't be prone to a down year (especially when success at the position is dependent on so many other factors). It also doesn't mean there aren't great WRs that take big year-to-year swings. But in fantasy football, I'm looking for consistency and reliability. And that's why I'm looking for those elite WRs that do produce the high numbers year in, year out.
That's why my #1 fantasy statistic for evaluating wide receivers is their total receiving yards for the past three seasons (to translate it into familiar single-season terms, I go ahead and average it out). I think this number will reliably show me what WRs are in their statistical primes. I think it will tell me who can be counted on for quality production from year to year. Sure, it's going to eliminate some players whose productivity hasn't stretched over three seasons, but that's fine; I don't want to spend a lot on flavor-of-the-month WRs when I could be drafting predictably reliable WRs (were you happy if you drafted Calvin Johnson for 2009 based on his breakout 2008 numbers?).
Based on this statistic, here is my list of the elite fantasy WR prospects for 2010: every WR who has averaged 1,200+ yards over the past three seasons. And of course this number can also determine the next tier of productive WRs: averaging 1,100+ or 1,000+ over three seasons is a sign of a productive fantasy WR.
1. Andre Johnson: 1,332
2. Larry Fitzgerald: 1,311
3. Reggie Wayne: 1,306
4. Randy Moss: 1,255
5. Roddy White: 1,246
6. Brandon Marshall: 1,237
7. Wes Welker: 1,229
Counterargument: There ain't no Santa Claus, and there ain't no magic number, either.
Your three-year-average system excludes breakout performers of the past two seasons (Sidney Rice, Vincent Jackson, NYG Steve Smith). Wide Receiver is a very team-dependent position, and your system doesn't account team circumstances, like a new QB (Larry Fitzgerald, CAR Steve Smith) or a new team (Anquan Boldin, Brandon Marshall). It doesn't account for WRs that get a lot of yards but not a lot of TDs (Wes Welker). It doesn't account for a WR who had one year of injuries, or one down year, or a year with backup/rookie/lousy QB. It doesn't account for aging WRs on the decline. Fantasy WR is an eclectic position: there are stud #1 WRs on run-first teams, there are productive #2 WRs on pass-first teams, there are possession receivers, there are deep threat receivers, there are small guys and big guys, there are guys that run a lot after the catch, etc., etc., etc.
Furthermore, what great insight does your list provide? You've basically made a list of WRs that everybody recognizes to be elite fantasy WRs (with the exception of Welker, who doesn't get TDs). At best, your system eliminates WRs that might get a lot of hype but that you deem unworthy of an expensive pick. I would argue, however, that it eliminates a lot of quality WRs that will be producing good fantasy numbers, and whom you might get cheaper than Andre freaking Johnson.
I do think there are certain singular statistics than can help you evaluate some positions (I'm partial to yards from scrimmage per game to evaluate RBs, but only from the previous season). But attempting to evaluate WRs based on a single statistic is bound to fail.