It’s become an annual tradition for Rock and Roll Hall of Fame expert Charles Crossley, Jr. to provide a detailed breakdown of the nominees. Here is his look at the artists on the 2012 ballot (reposted here with permission from his message board):

For reference, the nominees on this year’s ballot, from which the 2012 inductees will be selected by the R&RHoF voters (mostly current inductees and pop critics), are:
Beastie Boys
The Cure
Donovan
Eric B. & Rakim
Guns 'N Roses
Heart
Joan Jett & the Blackhearts
Freddie King
Laura Nyro
Red Hot Chili Peppers
Rufus
The Small Faces/The Faces
Spinners
Donna Summer
War

People over the years have claimed that the nominee ballot is calculated to meet certain criteria, such as there has to be dead people (or no dead people), there was to be so many of a certain race, there has to be so many of a certain gender. . .  So, let's break up these nominees and examine them based on all these different criteria, and see what the truth is.

First, by subgenre:

1 blues act
1 folk rock/psychedelic act
1 funk act
1 funk rock act
1 funk metal act
1 goth rock/alternative act
2 hard rock acts
1 hard rock/folk rock act
1 psychedelic/pub rock act
2 rap acts
1 R&B/soul act
1 singer/songwriter act

Next, by members.  Asterisks (*) indicate members specifically named in the press release.  Question marks (?) wonder if these members will be added because they did not appear on what is regarded as an "important" recording or have made only minor contributions to the act’s main recordings.  All others appeared on an important recording but weren't named on the press release.  Any members not listed either have not recorded with the act or have recorded on minor recordings past the act’s heyday.

Based on the membership of this year’s nominees, there are a total of 112 people who could possibly be inducted.  Based on who was included in past inductions, most of them won’t.

Beastie Boys - 3 (*Mike D, *MCA, *Ad-Rock)

The Cure - 12 (*Robert Smith, Michael Dempsey, *Lol Tolhurst, *Simon Gallup, Matthieu Hartley, Andy Anderson, Phil Thornalley, *Porl Thompson, *Boris Williams, *Roger O’Donnell, Perry Bamonte, Jason Cooper)

Donovan - (*himself)

Eric B. & Rakim – 2 (*Eric B., *Rakim)

Guns 'N Roses - 18 (*Axl Rose, *Slash, *Izzy Stradlin, *Duff McKagan, *Steven Adler, Dizzy Reed, Matt Sorum, Gilby Clarke, Buckethead, John Freese, Paul Tobias, Robin Finck, Bryan Mantia, Tommy Stinson, Chris Pitman, Richard Fortus, Bumblefoot, Frank Ferrer)

Heart - 10 (*Ann Wilson, *Nancy Wilson, *Roger Fisher, *Steve Fossen, *Michael DeRosier, *Howard Leese, Mark Andes, Dennis Carmassi, Fernando Saunders (?), Denny Fongheiser (?))

Joan Jett & The Blackhearts - 6 (*Joan Jett, Ricky Byrd, Gary Ryan, Lee Crystal, Kasim Sulton, Thommy Price)

Freddie King (*himself)

Laura Nyro (*herself)

Red Hot Chili Peppers - 15 (*Anthony Kleidis, *Hillel Slovak, *Flea, *Jack Irons, Jack Sherman, Cliff Martinez, Blackbyrd McKnight (?), D.H. Peligro (?), *John Frusciante, *Chad Smith, Zander Schloss (?), Arik Marshall, Jesse Tobias (?), Dave Navarro, Josh Klinghoffer)

Rufus With Chaka Khan - 14 (Kevin Murphy, Al Ciner, Dennis Belfield, Lee Graziano (?), Paulette McWilliams (?), Ron Stockert, *Chaka Khan, Tony Maiden, Nate Morgan, Bobby Watson, Andre Fischer, Hawk Wolinski, Moon Calhoun, J.R. Robinson)

The Small Faces/The Faces - 7 (*Steve Marriott, *Ronnie Lane, *Ian McLagan, *Kenney Jones, *Rod Stewart, *Ron Wood, Tetsu Yamauchi (?))

The Spinners - 9 (*Bobbie Smith, *Pervis Jackson, *Henry Fambrough, *Billy Henderson, George Dixon, Edgar "Chico" Edwards, G.C. Cameron, *Phillip Wynne, John Edwards)

Donna Summer (*herself)

War - 12 (*Lonnie Jordan, *Howard Scott, *Charles Miller, *B.B. Dickerson, *Harold Brown, *Papa Dee Allen, *Lee Oskar, *Eric Burdon, Alice Tweed Smyth aka Tweed Smith (?), Luther Rabb (?), Pat Rizzo (?), Ronnie Hammon (?))

Next, by previous inductions. Clyde McPhatter was the first person to be inducted more than once into the Rock & Roll Hall of Fame, as a soloist and as a member of the first incarnation of the Drifters. So, when someone is inducted more than once, we say he has joined the Clyde McPhatter Club. So, notice the name in bold above? Poised to join the Clyde McPhatter Club this year is:

Rod Stewart of the Faces, previously inducted solo (94).
Ron Wood of the Faces, previously inducted with the Rolling Stones (89).
Eric Burdon of War, previously inducted with the Animals (94).

Next, by race, depending on who is and who is not inducted:

White: 6
Beastie Boys, The Cure, Donovan, Heart, Joan Jett & the Blackhearts, Laura Nyro

Black: 4
Eric B. & Rakim, Freddie King, Donna Summer, The Spinners

Mixed: possibly 5
Guns ‘N Roses, Red Hot Chili Peppers*, Rufus, The Small Faces/The Faces**, War

*This depends on whether Cliff Martinez, Blackbyrd McKnight, Paul Tobias or Dave Navarro are inducted with the Red Hot Chili Peppers.  Otherwise, this act would count towards white.
**This depends on whether Tetsu Yamauchi is inducted with the Faces, which isn’t likely.  Otherwise, this act would count towards white.

Next, by gender, depending on which members are inducted:

Male: 104

Female: 8

It seems, despite what has been written to the contrary, there is no appreciable increase in the actual number of females that could be inducted this year over the last few years.

Next, by nationality based on place of birth:

Seven I cannot identify where they're from, but all seven are probably from the United States (Dennis Belfield of Rufus, Steve Fossen of Heart, Ronnie Hammon of War, Pat Rizzo of War, Gary Ryan of the Blackhearts, Alice Tweed Smyth from War, and Ron Stockert of Rufus)
One from Australia (Flea of the Red Hot Chili Peppers).
One from Denmark (Lee Oskar of War).
One born in France, raised in England (Boris Williams of the Cure).
One from Israel (Hillel Slovak of the Red Hot Chili Peppers).
One from Japan (Tetsu Yamauchi of the Faces).
One from Mexico (Paul Tobias of the Red Hot Chili Peppers).
One born in Southern Rhodesia (present day Zimbabwe), raised in England (Michael Dempsey of the Cure).
Nineteen from the United Kingdom (18 from England, 1 from Scotland).
The rest were from the United States of America:
20 from California, 1 from Delaware, 2 from Florida, 1 from Georgia, 6 from Illinois, 4 from Indiana, 1 from Iowa, 1 from Kansas, 2 from Louisiana, 1 from Massachusetts, 6 from Michigan, 3 from Minnesota, 1 from Mississippi, 5 from Missouri, 14 from New York, 2 from Ohio, 1 from Oklahoma, 2 from Pennsylvania, 1 from Tennessee, 1 from Texas, 4 from Washington

Next, by the number of top 40 hits on the Billboard 100:

Beastie Boys - 3
The Cure - 3
Donovan- 12
Eric B. & Rakim - 0
Guns 'N Roses - 9
Heart - 20
Joan Jett & the Blackhearts – 8 (including “Light Of Day” by the Barbusters)
Freddie King - 1
Laura Nyro - 0
Red Hot Chili Peppers - 9
Rufus - 10
The Small Faces/The Faces – 3 (1 as the Small Faces, 2 as the Faces)
The Spinners - 17
Donna Summer - 20
War - 12

Next, by dead members, depending on who is inducted.  Currently, there are 11:

Freddie King
Laura Nyro
Hillel Slovak of the Red Hot Chili Peppers
Steve Marriott of the Small Faces
Ronnie Lane of the Small Faces and the Faces
Pervis Jackson of the Spinners
Billy Henderson of the Spinners
Phillipé Wynne of the Spinners
Papa Dee Allen of War
Charles Miller of War
Luther Rabb of War

Next, by number of years eligible, with first national release.  An act is eligible 25 years after its first national release:

Beastie Boys 
First national release: 1982’s "Polly Wog Stew" ep
First year eligible: 2007
Number of years eligible: 5

The Cure 
First national release: 1978’s "Killing An Arab" single
First year eligible: 2004
Number of years eligible: 8

Donovan
First national release: 1965’s "Catch The Wind" album
First year eligible: 1990
Number of years eligible: 22

Eric B. & Rakim
First national release: 1986’s "Eric B. Is President" single 
First year eligible: 2011
Number of years eligible: 1

Guns 'N Roses 
First national release: 1986’s "Live ?!*@ Like A Suicide" ep
First year eligible: 2011
Number of years eligible: 1

Heart 
First national release: 1975’s "Dreamboat Annie" album 
First year eligible: 2000
Number of years eligible: 12

Joan Jett & the Blackhearts
First national release:  1981’s "I Love Rock-N-Roll" album
Excludes 1980’s Bad Reputation which was credited solely to Joan Jett.
First year eligible:  2006
Number of years eligible: 6

Freddie King
First national release: 1960’s "You've Got To Love Her With Feeling" single
Excludes 1957’s "Country Boy" single, which was a regional release
First year eligible:  1985
Number of years eligible: 27

Laura Nyro
First national release: 1967’s "More Than A New Discovery" album
First year eligible:  1992
Number of years eligible: 20

Red Hot Chili Peppers
First national release:  1984’s "Red Hot Chili Peppers" album
First year eligible:  2009
Number of years eligible: 3

Rufus With Chaka Khan 
First national release:  1974’s “Rags To Rufus” album
Excludes 1973’s "Rufus"  album, which was credited solely to Rufus even though Chaka Khan was present
First year eligible:  1999
Number of years eligible:  13

The Small Faces/The Faces
First national release:  1965’s "What'cha Gonna Do About It" single
First year eligible:  1990
Number of years eligible: 22
For the record, the first national release for The Faces was 1969’s "Flying” single

The Spinners
First national release:  1961’s "That's What Girls Are Made For" single
First year eligible:  1986
Number of years eligible:  26

Donna Summer 
First national release: 1971’s "Sally Go 'Round The Roses" single
First year eligible:  1996
Number of years eligible:  16

War
First national release:  1970 - "Eric Burdon Declares War" album
First year eligible:  1995
Number of years eligible:  17

Next, number of times nominated, including years nominated:

Beastie Boys – 3 (2007, 2010, 2011)
The Cure – 1 (2011)
Donovan – 2 (2010, 2011)
Eric B. & Rakim – 1 (2011)
Guns 'N Roses – 1 (2011)
Heart – 1 (2011)
Joan Jett & the Blackhearts 1 – (2011)
Freddie King – 1 (2011)
Laura Nyro – 3 (2009, 2010, 2011)
Red Hot Chili Peppers – 2 (2009, 2011)
Rufus – 1 (2011)
The Small Faces/The Faces – 1 (2011)
Spinners – 1 (2011)
Donna Summer - 4 (2007, 2009, 2010, 2011)
War – 2 (2008, 2011)

There are six previously nominated acts this year, while the other nine have been nominated for their first time. The nominators favored acts that have never been nominated over those who have.  Going by the inductees from the last six years, so do the voters.   

Thanks Charles, for all the work you put in to compile the information above. You can read more from Charles Crossley, Jr. on his Rock Hall forum and follow him on Twitter.