Oscar Predictions: Best Adapted Screenplay

It's time again for the Oscars. It's been a long Awards season as always. Guilds, Globes, BAFTAs, and critics have all made their picks  and I'm here to figure out what it all means. Yes, it's time again for my multi-part Oscar predictions.
I'm going to go through each category, tell you who has been nominated and won for what, give a context for what that means, and order the nominees from most to least likely to win on Oscar night. That doesn't mean I'll be right, but it does mean I'll be informed. Wish me luck.

Previously:
Nomination Reaction
Documentary, Animated, and Live-Action Short
Documentary Feature
Animated Feature 
Foreign Film
Visual Effects
Sound Mixing and Sound Editing
Makeup & Hairstyling 
Costume Design
Score and Song
Production Design
Cinematography
Film Editing
Adapted Screenplay
Original Screenplay
Supporting Actress
Supporting Actor
Lead Actress
Lead Actor
Director
Best Picture

Glossary:
BAFTA - British Academy of Film and Television Arts Awards
Golden Globe - Presented by the Hollywood Foreign Press Association  Award
WGA - Writers Guild of America Award

They sure don't make it easy to call the screenplay categories. Thanks to split categories, guild rules, and release date issues, it's amazing that there are any trends for the awards. The Adapted Screenplay award has three groups that I can consult for predictions.
The BAFTA award is the least useful. It's matched the Oscar winner only six times in the last 20 years. It's at least nominated the winner for the last 15 years though, so that's encouraging. The Golden Globes are marginally more useful most years. Not this year though. This is the first time in over two decades that the winner of the Golden Globe wasn't even nominated by the Academy. The only useful fact I can pull from that then is that 15 of the last 20 Oscar winners for adapted screenplay were at least nominated for a Golden Globe. The WGA is potentially the best indicator, if not for all the screenplays that are ineligible for an Oscar thanks to stricter rules. I could only get back 5 years, because tracking down which movies were ineligible in a given year became too much effort. In those five years, the WGA is 4/5 calling the Oscar winner. The one exception is in 2013 when 12 Years a Slave wasn't eligible for a WGA.

The Big Short
BAFTA - Adapted Screenplay - Winner
Golden Globes - Screenplay - Nominee
WGA - Adapted Screenplay - Winner
All this goes to say that The Big Short is close to a lock. I didn't care for the movie, but I have to say, the screenplay is a marvel in fitting as much information in as possible. It probably needs this win too for me to believe there's enough support for it to win the Oscar for Best Picture.

Room
BAFTA - Adapted Screenplay - Nominee
Golden Globes - Screenplay - Nominee
WGA - Ineligible
I'll assume that if it was eligible, the Room screenplay would've gotten a WGA nomination too, making it the only other movie in the field with three nominations. Room already scored a surprise nomination for the director. Perhaps support in the Academy is even deeper.

Carol
BAFTA - Adapted Screenplay - Nominee
WGA - Adapted Screenplay - Nominee
This really needed a win from the BAFTA or WGA for me to think it had a legit shot at winning.

Brooklyn
BAFTA - Adapted Screenplay - Nominee
WGA - Ineligible
The WGA ineligibility makes it a bit of a wildcard. Room looks far more intriguing from that angle though.

The Martian
WGA - Adapted Screenplay - Nominee
Absolutely deserves the nomination. This would be the highest grossing screenplay winner in either category since Return of the King in 2003.