Where do surprises come from? If we knew, they wouldn’t be surprises. But it’s probably worth looking at the slightly less mysterious matter of Oscar upsets, as the 7,000 or so voters of the Academy of Motion Picture Arts and Sciences cast their ballots between now and next Tuesday. By and large, Academy members are a predictable bunch, especially when it comes to the Best Picture award. Almost everyone knew Slumdog Millionaire, The King’s Speech and The Artist were anointed winners in their respective years. Any reporter who didn’t have a pre-written victory lede for 12 Years A Slave just wasn’t paying attention. Spotlight and Birdman were iffier, but not unforeseeable.

This year, it seems foolhardy to bet against La La Land. A win at the BAFTAs on Sunday signaled international support for a film that had already picked up bellwether awards from the Producers Guild, Directors Guild, Hollywood Foreign Press, Broadcast Film Critics and an array of others. In all, that’s enough to tag Damien Chazelle’s musical with that most dreaded word in the Oscar campaigner’s lexicon: La La Land is the “frontrunner.”

Still, there’s that troubling slight by the Screen Actors Guild, which gave its ensemble award to Hidden Figures. And there is a scary history of Oscar upsets. Not many. But just enough to keep awards partisans on edge until the last envelope is opened.

Shuffling through some dusty clips in the Academy’s Margaret Herrick Library, we were able to spot at least a few theories about upsets and what causes them. Among the supposed culprits:

Heffalumps: Technically, those would be scary elephants, more or less, as described in A. A. Milne’s Winnie The Pooh. Famously, Annie Proulx, who wrote the story on which Brokeback Mountain was based, blamed heffalumps for that film’s shocking defeat by Crash, which won the Best Picture Oscar in 2006. More specifically, in a post-Oscar rant published in Britain’s Guardian newspaper, Proulx contended that out-of-touch awards voters were too old, wealthy, insular, and thick-skulled to feel the innate power of a gay-themed cowboy film that had already won major awards from the very groups that have now honored La La Land.  “We should have known conservative heffalump Academy voters would have rather different ideas of what was stirring contemporary culture,” huffed Proulx.

Cultural conservatism would seem not to be a problem for La La Land. It has little in the way of overt social message; and the Academy heffalumps, if they ever existed, would likely rally to its industry-friendly motifs.

In a secondary theory, Proulx suggested that “Trash—excuse me—Crash” had been unfairly helped by a last-minute flood of DVDs unleashed on the voters by its distributor, Lionsgate. But at present, there is no sign that Lionsgate’s La La Land will be overwhelmed by an Oroville-like cascade of discs from any of its competitors.

The little guy: As unlikely as it may now seem, Miramax Films in 1999 credited Hollywood proletarians for the victory of its Shakespeare In Love, which upended Steven Spielberg’s Saving Private Ryan in the Best Picture race. There was an audible gasp in the Dorothy Chandler Pavilion when Shakespeare won, Miramax spokesman Mark Gill told the Los Angeles Times, because “the power elite of Hollywood voted for Saving Private Ryan, and they were all in the room.” Thousands of below-the-line workers, insisted Gill, had rejected Spielberg’s gritty World War II epic, rallying instead to Gwyneth Paltrow and John Madden’s British-made period romance.

Go figure. A prevailing counter-theory had it that Miramax and its co-chief Harvey Weinstein actually bought the Oscar, by spending a then shocking $15 million on seasonal ads. But DreamWorks gave as good as it got in the advertising department. In fact, Jeffrey Katzenberg, one of the company’s co-founders, had to make good on a bet with Warren Beatty when one (disputed) count showed that Ryan had out-advertised Shakespeare 165 pages to 118 in a designated counting period.

Yet another theory, less sexy, said Shakespeare’s win wasn’t an upset at all. Ryan, which was released to great fanfare in July, had simply lost steam as the season wore on, and a fresher film won the hearts of voters. If true, that could be a slight caution for La La Land, which has been around since a debut at the Venice Film Festival in late August. But almost everything in the Best Picture mix has been on screens nearly as long—even Hidden Figures, a December release, showed a substantial piece of footage at the Toronto International Film Festival in September. If fatigue is a factor, most of the contenders are touched by it.

Hubris. Over-reach was written all over The Aviator in the already fading clips and press-kits collected at the Herrick library. Martin Scorsese’s Howard Hughes biopic wasn’t just a front-runner; it was the presumptive winner. It had all the elements—scope, importance, and deep industry roots. No fewer than three famous actresses were playing actresses even more famous. Cate Blanchett was Katharine Hepburn. Kate Beckinsale was Ava Gardner. Gwen Stefani was Jean Harlow. Scorsese, of course, was overdue for honors: Five times nominated as Best Director, he had never won. And Miramax, in corporate turmoil, spread what should have been an effective whisper. As Variety wrote in November of 2004, this “could be Harvey Weinstein’s final Oscar season at the company.”

Most of all, the sense of entitlement was palpable in those self-important stills of Leonardo DiCaprio in character as Hughes, with pursed lips and knit brow, as he sat in the open cockpit of his plane or peered intently at his engineering models. Among critics and reporters, comparisons to Citizen Kane were legion—everyone seemed to have forgotten that How Green Was My Valley upended Kane for the Best Picture Oscar in 1942.

In 2005, The Aviator arrived on awards night with 11 nominations,and a pocketful of pre-Oscar victories, including what should have been a tell-tale a Producers Guild win. So there was an audible gasp in the press room when the film, after picking up five Oscars, including one for Blanchett, lost the big one to Clint Eastwood’s Million Dollar Baby.

But Eastwood’s film was all heart, kind of like La La Land. So it’s hard to see the stuff of fresh upset in the dusty old clips.