So heading into the Oscars, I found
this article from last year (before all the awards ceremonies took place), measuring the correlation between SAG wins and Oscar wins.
Up to and including the 2017 awards...
- Half of the best ensemble winners go on to win best picture. So there's no telling who'll win best picture from SAG. The Producer's Guild is usually a better predictor (8 out of 10 winning the Oscar), which would indicate Green Book winning best picture this year
- For over a decade, best actor has been the same at both, with the exception of 2017 (when Denzel won the SAG and Casey Affleck the Oscar). So it seems Rami is the clear frontrunner here.
- Of the previous decade, 7 of the 10 SAG winners had won best actress at the Oscars. So Glenn is definitely the frontrunner now, though it's not a clear runaway.
- Other than 2 years (2012 and 2015), the past decade has seen the SAG winner for supporting actor go on to win Oscar gold. So looks like Mahershala will be getting a second Oscar.
- The last decade has had perfect correlation between supporting actress, with the only twist being Kate Winslet winning supporting actress at the SAG and going on to win best actress for the same film at the Oscars (that's the year Penelope Cruz won at the Oscars for supporting actress). This one will definitely not match this year, as Emily Blunt is not nominated for an Oscar.