Pre-draft tiers (via clustering on 59 expert rankings)

Quarter Backs:

My model for tiering QB's is simple.  I take the average rankings of 59 experts provided by fantasypros, plot them in one-dimenstional space, and apply a gaussian mixture model clustering algorithm to discover the natural tiers.  This is what you get:
qb1The first thing I noticed was the substantial drop off after Tony Romo, who is the #12 QB.  This partially why people are advocating delaying your QB pick this year -- because in a 12 man league, even if you have the worst starting QB in your league (Romo), you're not that far behind.
If you are in a 14+ person or 2 QB league, you might want to think twice before passing on Romo for Eli Manning or Roethlisberger. Let's zoom in and take a closer look at the top 12.
qb3The grey bars are the standard deviations for each player.  You could call Stafford a better pick than RG3 or Kaepernick, sure. But given how close they are, I would argue that there is enough variance between QB7-QB12 that if you don't get Ryan or better, it may be wiser to fill out the rest of your team first, knowing that you can still start Romo.
Here is my QB tier list.  I've underlined tiers with significant drop offs.
Tier 1: Aaron Rodgers, Drew Brees
Tier 2: Peyton Manning, Cam Newton
Tier 3: Tom Brady, Matt Ryan
Tier 4: Matthew Stafford, Colin Kaepernick, Robert Griffin III, Andrew Luck, Russell Wilson, Tony Romo
Tier 5: Eli Manning
Tier 6: Ben Roethlisberger, Andy Dalton
Tier 7: Jay Cutler, Josh Freeman, Joe Flacco, Philip Rivers
Tier 8: Michael Vick, Sam Bradford, Carson Palmer, Matt Schaub, Ryan Tannehill
Tier 9: Alex Smith
, Jake Locker, Brandon Weeden, E.J. Manuel, Christian Ponder, Matt Flynn, Geno Smith, Nick Foles, Chad Henne

Wide Receivers:

Let's apply the same thing to WR's.  I've updated both my WR and RB tier lists with this model, which I like better because it doesn't depend on the number of teams in your league.  I'll save this discussion for another time, but models that do that (such as value based drafting) are quite sensitive to the depth of the league and you should be careful if your league is not the same depth .
wr100 copyYou can see some visible drop offs here: Thomas-Fitzgerald, Jackson-Colston, Smith-Shorts. Smith is WR25, so there are just enough wideouts to go around for everyone's first and second slots. If you're in a 10 man league, half the teams will have all 3 WR's better than Smith. Let's look closer at the top 25:wr1-25 copyYet another confirmation of the "Calvin Johnson is his own tier" theory.  The Fitzgerald drop off is understandable as there are lots of question around his talent with his new QB. So is the Colson drop off, as he's never been in true WR1 territory with Jimmy Graham around.  Jackson is conveniently ranked at WR12, so take note if anyone manages to grab two wide outs at his tier or better.
It is interesting to see that the algorithm found Amendola and Welker together -- both similar style receivers with new teams, so there is no way to tell which will be better. Math works!wr26-53 copyThe middle tiers are interesting.  If you don't manage to grab Boldin or Lance Moore (who are WR38 and WR39), you're in for a long ride with Oakland's Denarius Moore.
percy-maclin copywr53-84 copy
As you can see, Percy Harvin and Jeremy Maclin are off the charts right now, understandably.  But even if we remove them, WR54 and higher is a noisy mess.  Qualitative arguments and inside scoops are probably better here for picking sleepers.  I refer you to the actual experts on this matter.
Here is the WR tier list:
Tier 1: Calvin Johnson
Tier 2: A.J. Green, Dez Bryant, Brandon Marshall, Julio Jones, Demaryius Thomas
Tier 3: Larry Fitzgerald, Roddy White, Andre Johnson, Randall Cobb, Victor Cruz, Vincent Jackson
Tier 4: Marques Colston, Jordy Nelson
Tier 5: Dwayne Bowe, Reggie Wayne, Hakeem Nicks
Tier 6: Danny Amendola, Wes Welker
Tier 7: Torrey Smith, Eric Decker, Antonio Brown, Pierre Garcon, Mike Wallace, Steve Smith
Tier 8: Cecil Shorts, James Jones, Steve Johnson, Greg Jennings
Tier 9: Danario Alexander, DeSean Jackson, Mike Williams, Miles Austin, Ty Hilton
Tier 10: Josh Gordon, Tavon Austin, Kenny Britt
Tier 11: Anquan Boldin, Lance Moore
Tier 12: Denarius Moore, Sidney Rice
Tier 13: Emmanuel Sanders, Kendall Wright, Justin Blackmon, Michael Floyd
Tier 14: Chris Givens, Alshon Jeffery, DeAndre Hopkins, Brian Hartline, Golden Tate
Tier 15: Vincent Brown, Ryan Broyles, Aaron Dobson
Tier 16: Darrius Heyward-Bey, Rueben Randle, Malcom Floyd, Cordarrelle Patterson, Greg Little, Brandon LaFell, Santonio Holmes
Tier 17: Andre Roberts, Rod Streater, Mohamed Sanu, Jeremy Kerley, Julian Edelman, Brandon Lloyd
Tier 18: Brian Quick, Jacoby Jones, Robert Woods, Nate Burleson, A.J. Jenkins, Stephen Hill, Joseph Morgan, Jon Baldwin
Tier 19: Keenan Allen, Santana Moss, Riley Cooper
Tier 20: Markus Wheaton, Nate Washington, Davone Bess, Donnie Avery, Michael Crabtree

Running Backs:

Here's the vertical plot of running backs:
rb-top50 copyAs you can see, you're probably going to want two RB's above Davis Wilson, who is RB21 on the list. That means in a 12 team league, 3 teams will have to settle for Bell or worse.
rb-1-21 copyThe first substantial gap come before Matt Forte.  This isn't surprising as Forte is the highest RB1 that loses significant fantasy points to his backup.
Take note of the drop offs after Morris (RB10), Jackson (RB12) and MJD (RB15).  This begs the question, at which point should you go RB-RB with your top two picks? Obviously there is no correct answer as you need to consider other positions as well.  A big factor will be if Richardson/Morris or better falls.  Another factor is if you can get Demarius Thomas or better in the second round, since there are only 6 tier 2+ wide outs.
Around RB17-RB21 (Reggie Bush to David Wilson), you can see the variance begins to grow. Certainly don't feel bad about taking Miller over Murray or Wilson over McFadden if you've have bad experiences with them in the past.rb-22-36 copyThe distance spanning Bell to Green-Ellis (RB22 to RB32) is large.  See the vertical plot if you don't believe me. That means there's going to be significant differences in each teams RB3. The sooner you can get yours the better.
For deeper leagues, you can use the this late rank RB chart to help you: rb-37-64 copy
Tier 1: Adrian Peterson
Tier 2: Doug Martin, Arian Foster, Jamaal Charles
Tier 3: C.J. Spiller, Marshawn Lynch, Ray Rice, LeSean McCoy, Trent Richardson
Tier 4: Alfred Morris
Tier 5: Matt Forte, Steven Jackson
Tier 6: Stevan Ridley, Chris Johnson, Maurice Jones-Drew
Tier 7: Frank Gore, Reggie Bush, DeMarco Murray, Lamar Miller, Darren McFadden, David Wilson
Tier 8: Le'Veon Bell, Darren Sproles
Tier 9: Christopher Ivory, Montee Ball
Tier 10: Ryan Mathews, Ahmad Bradshaw
Tier 11: Eddie Lacy, Rashard Mendenhall, Giovani Bernard, Shane Vereen
Tier 12: Andre Brown, BenJarvus Green-Ellis
Tier 13: Mark Ingram, DeAngelo Williams, Jonathan Stewart
Tier 14: Bernard Pierce, Bryce Brown, Fred Jackson, Daryl Richardson, Vick Ballard, Ben Tate, Isaiah Pead
Tier 15: Ronnie Hillman, Johnathan Franklin, Pierre Thomas, Mikel Leshoure, Danny Woodhead
Tier 16: Zac Stacy, Jacquizz Rodgers, Shonn Greene, Ryan Williams
Tier 17: Michael Bush, Knowshon Moreno
Tier 18: Marcel Reece, Mike Goodson, Bilal Powell, Joseph Randle, LaMichael James, Joique Bell
Tier 19: Daniel Thomas, Robert Turbin, Kendall Hunter, Jonathan Dwyer

Tight Ends:

For tight ends, most of what is here is already known.te-top30 copyGraham occupies tier 1 by a wide margin... no surprises.  The top 5 tight ends (Graham, Gronk, Witten, Gonzalez, Davis) are probably worth fighting for.  If you don't manage to get Rudolph (TE7) or better, I would recommend postponing your TE pick until much later.te-1-24 copy
Tier 1: Jimmy Graham
Tier 2: Rob Gronkowski, Jason Witten, Tony Gonzalez, Vernon Davis
Tier 3: Greg Olsen, Kyle Rudolph
Tier 4: Owen Daniels, Jared Cook, Antonio Gates, Martellus Bennett, Jermichael Finley, Brandon Myers
Tier 5: Brandon Pettigrew, Jermaine Gresham, Fred Davis, Jordan Cameron
Tier 6: Robert Housler, Ed Dickson, Dustin Keller
Tier 7: Heath Miller, Dwayne Allen, Tyler Eifert, Coby Fleener
Don't forget to follow me on twitter to catch my PPR list, and I'll also tweet my week-to-week tier lists as they become available.