And the winner is... not necessarily the best film of the year

In an effort to boost dwindling TV audiences for the Academy Awards, the number of films nominated for Best Picture has doubled from five to 10. This means more box-office hit movies are in the final line-up, following controversies including the question of how the very popular Batman – The Dark Knight missed out on a nomination in 2008.

A system of preferential voting will replace the old first-past-the -post method used since the 1940s. A change had to come, otherwise, with a field of 10 contenders, a film with only 11 per cent of the vote could win the coveted Oscar statuette. The argument is the same one we hear used against our current UK parliamentary voting system.

So now the 6,000 members of the Academy indicate preferences and, if no film wins an outright 50 per cent, then the film with fewest votes is eliminated, and its votes are allocated to movies ranked in second place. The process is repeated until a winner emerges.

Pundits disagree on the effect the new system will have. Avatar and The Hurt Locker are favourites, but some think Quentin Tarantino's Inglourious Basterds could win many second choice votes and cause an upset.

Nomination talk, who wears what dress and how good the presenter's jokes were at the Oscars are all in their way good for the industry, and there will always be post-awards chat among film fans about whether the "right" film was chosen, says Sheldon Hall, senior lecturer in film studies at Sheffield Hallam University.

"Best film" is very much a subjective notion, he says, and film fans do love to debate what the award "best picture" is actually rewarding. Take the race in 2003, when The Lord of the Rings: The Return of the King won, beating off competition from Master and Commander, Mystic River, Seabiscuit and Lost in Translation.

"I'd have preferred one of the others to win, but this was a clear case of a movie rather than a person winning for lifetime achievement, ie it won for the whole three-part saga. The Rings films bored me to tears, but I can see why it won. (As with Avatar this year) technical achievement plus commercial success and sheer logistical challenge make three powerful arguments."

In Dr Hall's view the best picture gong for Titanic in 1997 was for the worst film among that year's nominees. This year the might of Avatar and its massive technical accomplishment, in James Cameron's first narrative film since Titanic, is likely to be rewarded for the sheer difficulty and wizardry involved in making it. "In all fairness, I can't think of a year in which a really rotten movie won, although I thought Crash in 2005 was the worst choice of recent years. But usually winners are defensible in some way, and they always serve as a useful benchmark of what the industry really admires at any given moment. In other words, the winners tell us what film most voters would like to have made themselves."

We shouldn't underestimate how much money matters, though, says Dr Hall. "Avatar, which simultaneously opened in 50 countries and grossed $1bn dollars within a month, doesn't manage that by only appealing to 16-year-old male computer geeks. It has the widest possible appeal across men and women of all ages, including some who perhaps don't regularly go to the cinema. And it will, like Titanic, stay in cinemas for four or five months. For Academy voters, part of the measure of artistic merit is entertaining the biggest possible audience with a well-crafted film."

It sounds as though the voting may well err in the direction of Avatar, then – although the drama of an upset can be icing on the cake for anyone who stays up half the night. Sadly for the other very worthy contenders - The Hurt Locker, An Education, Inglourious Basterds and Up In The Air among them – it's not such a good year to be a nominee.

But then the Academy Awards are littered with glorious also-rans. Look at 1939 (officially Hollywood's "greatest year") Gone With The Wind carried off the best picture prize, yet its rivals, The Wizard of Oz, Dark Victory, Stagecoach, Wuthering Heights and Goodbye Mr Chips, were all exceptional films, too.

n Sheldon Hall's book Epics, Spectacles and Blockbusters – A Hollywood History, co-written with Steve Neale and published by Wayne State University Press, will be available in the UK from the end of April.

WHO SHOULD HAVE WON...

1942: The Magnificent Ambersons instead of Mrs Miniver

1948: The Red Shoes instead of Hamlet

1952: The Quiet Man instead of The Greatest Show on Earth

1969: Hello Dolly! instead of Midnight Cowboy

1971: The Last Picture Show instead of The French Connection