When sizing up Ruby Dee's chances of duplicating her SAG victory at the Oscars, it's important to weigh the history of the two awards, which have only co-existed since 1994. They've agreed 8 times in 13 years, but 5 of those were in the past 5 years.
Note that the extraordinary amount of recent agreement between SAG and Oscar can be seen among nominees, too: in 2005 and 2006 the lists in the supporting-actress race were the same. This year the nominee overlap was 4 for 5, with Saoirse Ronan ("Atonement") replacing SAG contender Catherine Keener ("Into the Wild") at the Oscars.
Remember, there used to be a lot more time in between these two awards, but when the Oscars moved up on the calendar four years ago, SAG moved up, too. Now they're scrunched much closer in time. Also keep in mind that the two groups share many of the same voters. All 1,300 members of the academy's acting branch belong to SAG. There are a lot more guild members, of course (more than 100,000 total; 2,100 are on SAG's nominating committee), but they're all like-minded people. Heck, if Gallup and Harris can get an accurate take on the national opinions of 300 million Americans by polling 1,500 people, then it's logical to assume that the views of SAG and AMPAS overlap a great deal despite the gap in numbers.
Here's a look back on this SAG race since 2000:
X - "Jennifer Hudson, "Dreamgirls"
Adriana Barraza, "Babel"
Rinko Kikuchi, "Babel"
Abigail Breslin, "Little Miss Sunshine"
Cate Blanchett, "Notes on a Scandal"
NOTE: All five nominees lined up.
X - "Rachel Weisz, "The Constant Gardener"
Michelle Williams, "Brokeback Mountain"
Catherine Keener, "Capote"
Amy Adams, "Junebug"
Frances McDormand, "North Country"
NOTE: All five nominees lined up.
X - "Cate Blanchett, "The Aviator"
Sophie Okonedo, "Hotel Rwanda"
Laura Linney, "Kinsey"
Virginia Madsen, "Sideways"
Cloris Leachman, "Spanglish"
NOTE: At the Oscars, Natalie Portman ("Closer") replaced SAG nominee Cloris Leachman.
X - "Renée Zellweger, "Cold Mountain"
Holly Hunter, "Thirteen"
Patricia Clarkson, "Pieces of April"
Keisha Castle-Hughes, "Whale Rider"
Maria Bello, "The Cooler"
NOTE: At the Oscars, Castle-Hughes was nominated in the lead race and Bello wasn't nominated at all. Instead, "Marcia Gay Harden ("Mystic River") and Shohreh Aghdashloo ("House of Sand and Fog") filled out this lineup.
X - "Catherine Zeta-Jones, "Chicago"""
Queen Latifah, "Chicago""
Julianne Moore, "The Hours""
Kathy Bates, "About Schmidt"
Michelle Pfeiffer, "White Oleander"
(NOTE: Pfeiffer wasn't nominated at the Oscars. Instead, "Adaptation" star Meryl Streep took her place.)
X - "Helen Mirren, "Gosford Park"
Cate Blanchett, "Bandits"
Dakota Fanning, "I Am Sam"
Judi Dench, "The Shipping News"
Cameron Diaz, "Vanilla Sky"
NOTE: Mirren was nominated at the Oscars, but got usurped by Jennifer Connelly ("A Beautiful Mind") who was placed in the lead race by SAG nom com. The other four SAG nominees did not make the Oscar list. Instead, academy contenders were: Maggie Smith ("Gosford Park"), Kate Winslet ("Iris") and Marisa Tomei ("In the Bedroom").
X - "Judi Dench, "Chocolat"
Kate Hudson, "Almost Famous"
Frances McDormand, "Almost Famous"
Julie Walters, "Billy Elliot"
Kate Winslet, "Quills"
NOTE: Here's the notorious year where a star won at the Oscars after not being nommed by SAG — the only time that's ever happened. Yeah, we're talking Marcia Gay Harden ("Pollock"). The only SAG nominee who didn't make the Oscar list was "Quills" star Winslet.