Despite equal representation of male and female filmmakers at this year's Sundance Film Festival, a new study shows there has been little change in the number of women working as directors and producers at the independent-film showcase over the past decade.

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But women still fare better behind the camera in independent film than in studio productions.

The Sundance Institute and Women in Film commissioned the study last year and announced the results Monday in Park City, Utah.

Researchers at the University of Southern California's Annenberg School for Communication and Journalism examined gender disparity in American narrative and documentary films shown at Sundance from 2002 to 2012.

Study director Stacy L. Smith and her team assessed the gender of more than 11,000 directors, writers, producers, cinematographers and editors of the 820 narrative and documentary films shown over this period and found that women represent less than one-third of those filmmakers.

"There has been no sustained or meaningful change across the last 11 years in the percentage of directors or producers at the Sundance Film Festival," Smith said.

There are more women working in documentary films than narrative films, but Smith said the research finds that "as commerce moves in, females move out".

The study found that female directors comprise a norm of 22.2 percent of narrative competition films and 14.5 percent of premieres and other non-competition films at Sundance over the past 11 years. During the same period, female directors made up only 4.4 percent of the top-grossing Hollywood films, a ratio of more than 15 male directors for every female. Of those women, though, more than 40 percent had come through the filmmaking programs of the Sundance Institute.

Women and men participate in the institute's programs in almost equal number, Smith said.

Female filmmakers find more equal representation in the documentary sphere, comprising nearly half of those represented at Sundance from 2002 to 2012.

Finally, the study found that films directed by women employ greater numbers of women behind the camera than those made by men.

The Sundance Institute and Women in Film aim to use the results of this study to create mentoring and support programs to increase the number of women working behind the camera in American filmmaking.