"Clearly, the norm in Hollywood is to exclude girls and women from the screen," the authors wrote. "It is also to misrepresent them."
The analysis of 30,835 characters reveals an "epidemic of invisibility," Smith said. All but three in last year's marquee roles were white. None older than 45 held a lead part. No lesbian, bisexual or transgender figures were prominently featured.
Most female characters showed up in domestic roles, the type society labels traditionally feminine. Nearly a third wore "sexy attire," compared to 8 per cent of men. Twenty-six per cent flashed skin, while nine per cent of men did the same.
Not to say there's anything wrong with being a stay-at-home mum or a teacher or a nurse or someone who likes to show off their body, Smith said. But she said it's important to convey to the little girls watching that women, of all ages, do far more.
These trends persist because Hollywood executives think attracting a male audience will bring box office success, researchers said. Hollywood executives, as well as the creative types behind the movies, they note, are mostly white men.
In 2014, men occupied most jobs behind the cameras, according to the report. Only two women directed across the top 100 films. They made up 11.2 per cent of writers and 18.9 per cent of producers. The representation shrinks drastically for women of color. Since 2007, only three black women directed across the top 700 films.
The films that did employ female writers featured more women of all ages in the cast, playing more prominent roles, the USC authors noted. And previous research shows movies with more women, developed beyond one-dimensional caricatures, are generally popular among viewers.
A recent FiveThirtyEight analysis of 1,615 films found those that pass the Bechdel Test (films with at least two named women who talk to each other about something other than men) tend to have lower budgets but hold their own at the box office. "Despite a commonly held belief among producers," wrote data journalist Walt Hickey, who led the project, "there is little statistical evidence to support the idea that movies featuring women do worse than films that don't."
These movies also receive more positive reviews, an average of 1.8 more Metacritic points by professional reviewers and 0.12 fewer stars by IMDb reviewers, according to Brian Keegan, a research fellow in computational social science at Northeastern University.
The Hunger Games: Mockingjay - Part 1, which grossed more than $500 million worldwide in its first two weeks, is further evidence. "That should shatter the assumption that girls will watch stories about boys," Smith said, "but boys won't watch stories about girls."