The Oscars are supposed to reward the best films and performances of the year. But in reality, lots of other factors influence who gets their hands on a golden statuette.
Do the Oscars pick the best films? "God, no," laughs film critic Thelma Adams. "That's the simple answer."
There are plenty of winners from Academy Awards history that stand the test of time. But there are many examples where film buffs look back and think: "Really?"
One of the biggest travesties occurred in 1959 when Gigi, a sub-My Fair Lady musical, won nine Oscars.
Alfred Hitchcock's Vertigo, which one 2012 poll decided was the best film ever made, went home with nothing.
More recently, Crash (best picture, 2006) and Birdman (best picture, 2015) are now seen by many as dodgy choices - especially considering they beat bold cowboy relationship drama Brokeback Mountain and growing-up epic Boyhood respectively.
How do Oscar-winning films measure up?
If you compare the best picture Oscar winners of the past two decades with the top-ranked movies of each year, the Oscars don't usually pick the year's best films.
Metacritic, a website that gives each film a score based on reviews from film critics, is one way of determining what films did best with the experts.
According to critics, between 1996 and 2016:
- The best-rated best picture winner was 2013's 12 Years a Slave (Metacritic score = 96/100)
- The best-rated best picture nominee was 2014's Boyhood (100/100)
- The worst-rated winner was 2000's Gladiator (64/100)
- The worst-rated nominee was 2011's Extremely Loud and Incredibly Close (46/100)
So the quality of Oscar winners and nominees is variable. But are critics really any more in touch than Oscar voters with what film fans really like?
"American critics are biased," says Thelma Adams. "They are majority white and are looking at movies through a highly educated, professional class, white male lens."
But what other measures of cinematic quality could we use? Box office takings give a democratic picture of popularity, yes - but quality?
Then there are the IMDB rankings, which are based on votes by film fans.
According to IMDB (Internet Movie Database), 1994's The Shawshank Redemption is the best film ever made - but it didn't win any Oscars.
Proof, perhaps, that there's no sure-fire way of judging "the best".
What influences who wins an Oscar?
- Who's hot?
The Oscar race is about buzz and momentum.
Around 7,000 members of the Academy of Motion Picture Arts and Sciences vote, and final voting takes place just two weeks before the ceremony, so a lot rests on which names are being talked about at that time.
It's also about crowning an actor or actress whose "time" has appeared to have "come". That's partly why La La Land's Emma Stone could beat her more seasoned rivals to the best actress prize on Sunday.
"The Oscars are about Miss Right Now, as opposed to Miss Right," says Sasha Stone, who runs the Awards Daily website. "That's a Robin Williams joke, but it's a good one.
"It's about the difference between long-term committed love and a flurry of new love, and you have to capture the right moment for a film to win. It really is a momentary crush."
- Who's overdue?
Martin Scorsese didn't win an Oscar for 1976's Taxi Driver, or 1980's Raging Bull, or 1990's GoodFellas. He finally won best picture, and best director, for 2006's The Departed.
"The Departed is not by any stretch of the imagination Martin Scorsese's best movie," says Thelma Adams. "But he was in some ways overdue."
Similarly, when Leonardo DiCaprio won for The Revenant last year after four unsuccessful nominations, there was a strong feeling that it was about time.
- Who's run the best campaign?
Just like in an election, some nominees hit the campaign trail hard.
They do talk shows. They schmooze Academy members at functions. They are funny and charming at other award ceremonies.
By most people's estimations, Eddie Redmayne conducted a textbook campaign when he beat Michael Keaton to the best actor Oscar in 2015.
Then there's the darker side of campaigning. "I don't think people realise how political the Oscars are," Sasha Stone says.
"There are a lot of smear campaigns that go on, whisper campaigns. It's really competitive because money is at stake."
- Who fits the template?
Of all Academy members, 89% are white and 73% are male. And that's after the Academy's recent attempts to make its membership more diverse.
Not to suggest they're deliberately prejudiced. But it perhaps helps explain why - for example - there were no non-white acting nominees in 2015 and 2016.
Oscar voters also seem to prefer their winning women to be younger than the men. The average best actress winner is 10 years younger than the average best actor.
Women, on average, win in their mid-thirties, while men are in their mid-forties.
As for the types of films that voters go for when choosing best picture, they tend to be ones that retain both cinematic credibility and mass appeal
"If you look back, you see the winners tend to be high middlebrow," says Thelma Adams by way of explanation.
- Who plays a real person or an actor?
Every best picture winner since 2010 has fallen into one of two camps.
They have either been a real-life story about characters who battled some sort of adversity or injustice (Spotlight, 12 Years a Slave, Argo, The King's Speech).
Or else they've been about acting and the film industry (Birdman, The Artist, Argo again). La La Land, this year's hot favourite, looks likely to join the latter list.
The Academy also likes actors and actresses who transform themselves into real, complex figures. Stars have won in recent years for playing the likes of Stephen Hawking, Abraham Lincoln, Margaret Thatcher and George VI.
- Who can everyone agree on?
The films and performances that some people passionately love also tend to be those that other people hate.
According to Thelma Adams, awards are often about finding the consensus option that everyone can agree is pretty good.
Adams was in the New York Film Critics Circle for 19 years and helped decide on that organisation's awards. Their winning movie, she says, "was often the movie that you could live with".
"It has to be a movie that everybody kind of likes," she goes on. "So the movies that you're passionate about often don't make it."
Ten films that didn't win any Oscars
- It's a Wonderful Life (lost 1946 best picture Oscar to The Best Years of Our Lives)
- Singin' in the Rain (not up for 1953 best picture Oscar, which went to The Greatest Show on Earth)
- 12 Angry Men (lost 1958 best picture Oscar to The Bridge on the River Kwai)
- Vertigo (not up for 1959 best picture Oscar, which went to Gigi)
- Psycho (not up for 1961 best picture Oscar, which went to The Apartment)
- Once Upon a Time in the West (not up for 1970 best picture Oscar, which went to Midnight Cowboy)
- Taxi Driver (lost 1977 best picture Oscar to Rocky)
- The Shawshank Redemption, above (lost 1995 best picture Oscar to Forrest Gump)
- Toy Story (not up for 1996 best picture Oscar, which went to Braveheart)
- Fight Club (not up for 2000 best picture Oscar, which went to American Beauty)
Ten stars who haven't won a competitive Oscar
- Peter O'Toole, above (eight nominations)
- Richard Burton (seven)
- Glenn Close (six)
- Deborah Kerr (six)
- Thelma Ritter (six)
- Amy Adams (five)
- Albert Finney (five)
- Annette Bening (four)
- Montgomery Clift (four)
- Ed Harris (four)
When did the Oscars get it wrong?
Thelma Adams, The Observer and GoldDerby.com
Titanic (best picture, 1998): "I don't think Titanic should have won. I don't think it holds up as a script. You could cut the whole first hour. It's really ultimately a story about class and save the rich people first.
"The best movie of that year was The Sweet Hereafter, which was nominated for best director."
Sasha Stone, AwardsDaily.com
Crash (best picture, 2006): "Probably the worst example was Brokeback Mountain and Crash. I still think that stands out as one of the worst losses.
"I do think Brokeback Mountain was a much better movie and time has proven that to be the case. I don't think Crash has really stood the test of time."
Brian Truitt, USA Today
The Hurt Locker (best picture, 2010): "Kathryn Bigelow's good but not great war movie bested a host of stand-outs - Up, Precious and Avatar among them - even though it was the lowest-grossing best picture winner in recent history.
"What should have won: Inglourious Basterds, the World War II revenge fantasy that's arguably Quentin Tarantino's finest work."
Jason Wood, artistic director of film at Home, Manchester, and professor of film at Manchester Metropolitan University
Life is Beautiful (best foreign language film, 1999): "I would have to pick the award of an Oscar to Life is Beautiful in this category as the worst error of judgement.
"It is a crime against art. They should still be embarrassed. Central Station should have been the recipient."
Larushka Ivan-Zadeh, Metro
Going My Way (best picture, 1945): "The years have not been kind on this charming but schmaltzy, overlong Bing Crosby musical.
"However, it was 1944, World War Two was thundering on and, as La La Land may prove, musicals do well in dark times.
"This one was a box office smash. Should've won: Double Indemnity."
Susan Wloszczyna, RogerEbert.com and ex-USA Today
Rocky (best picture, 1977): "The uplifting, blue-collar tale of a struggling boxer provided an emotional high for audiences that worthier and far more influential nominees such as Taxi Driver, Network and All the President's Men did not.
"After the turmoil of Watergate and the Vietnam War, this is what those celebrating America's bicentennial year needed.
"You can't say Rocky wasn't a success. But those three other movies are seen as classics of their kind, while underdog sports dramas are a dime a dozen."