A lot of the information in the report isn’t new, even if it remains newsworthy. Among other things, the findings are a blunt reminder that female-driven blockbusters like “The Hunger Games” and African-American dramas like “Selma” remain exceptions in a largely homogeneous field. Art may be a mirror of life, but it is often a badly distorted one in mainstream American cinema.

Image Lena Headey in “300: Rise of an Empire.” Credit... Warner Bros. Pictures

And, while women may be about half of the population — and for years have bought half the movie tickets — they remain a persistent minority on screen. The same is true of certain races and ethnicities, despite the utopianism of movies like the “Fast & Furious” series. The report found that 4.9 percent of all speaking or named characters in the 100 top-grossing movies of 2014 were “Hispanic/Latino.” As the report points out, this low number is at odds with off-screen demographics: Latinos were 17.1 percent of the population in 2013. And in 2014, they were also 25 percent of what the industry calls frequent moviegoers.

The “Inequality” report comes at a time of increasing criticism about the industry’s on-screen and off-screen practices, giving further empirical support to what has become a steady stream of righteous complaint. In May, the American Civil Liberties Union sent letters to state and federal agencies seeking an investigation of the hiring practices of the major Hollywood studios, networks and talent agencies. That same month, Senator Barbara Boxer, Democrat of California, and four other female senators sent a letter to the major studios asking them to respond to an earlier Annenberg/University of Southern California study that found that only 4.1 percent of top-grossing films over the last decade had female directors.

Image Scarlett Johansson in “Captain America: The Winter Soldier.” Credit... Marvel Studios and Walt Disney Pictures

The “Inequality” report is part of a growing wealth of data about the industry’s practices that are, study by study, making the case for change. Dr. Smith also helped write that earlier study and was one of the principal researchers — along with Marc Choueiti and Katherine Pieper — on a widely publicized multiyear study done with the Sundance Institute and Women in Film on the crisis facing female directors. For the “Inequality” study, they were joined by a team that swelled to an estimated 70 to 80 people; most of the team members are undergraduate students. Dr. Smith said on Friday that it was one of her students who had inspired her to start looking at the representation of lesbian, gay, bisexual and transgender characters, which is in keeping with studies that show that young Americans tend to be liberal in their political and social views. (She declined to name the student, citing privacy concerns.)