Barbie was an undeniable hit, raking in $US1.45 billion ($2.03 billion) at the worldwide box office.

Avatar: The Way of Water grossed more than $US2.3 billion ($2.85 billion) globally and is the third highest-grossing film in history.

These films have something in common.

Women played a role in co-writing the films and, in the case of Barbie, directing.

A new analysis, Women in Directing and Screenwriting: The Capital Allocation Puzzle in Commercial Film, has found movies with a female screenwriter returned higher median profits than male-only productions.

The Frontiers in Communication study covered 30 years of film, including theatrical and non-theatrical releases.

"Films with a woman screenwriter but no woman director had 34 per cent higher median profits than films with only men in those roles, despite similar budgets," said Anja Huwiler, the study's author and a researcher at Johannes Gutenberg University Mainz.

 "Yet 39 of the 44 films in the top 1 per cent of production budgets were male-only productions, and none involved a woman director."

Films written but not directed by women with budgets comparable to male-only productions generated the highest median profit.

Movies written but not directed by women also generated a higher return on investment.

Films in which women had both screenwriting and directing roles achieved a similar return on investment to male-only films when operating on half the budget.

While films written by women made more money, movies with higher budgets were male-dominated.

"The extreme uncertainty of film financing can make familiar people and established ways of working feel safer, especially when decision-makers are risk- or loss-averse," said Ms Huwiler.

"This can reinforce the status quo even when the financial evidence points elsewhere."

The report also found that the share of films crediting at least one woman as a director or screenwriter was growing at a sluggish pace.

After the #MeToo movement in 2017, women's participation rose, but the study found no lasting acceleration in the rate of growth.

Men hold privileged position 'not earned'

Senior lecturer in screenwriting at the University of Melbourne Radha O'Meara said the findings of the report were in line with what she sees in the Australian screen industry, despite the international focus.

"Gender discrimination in the Australian screen industry is often couched in the language of financial risk, and this report confirms that men screenwriters and directors are actually the greater financial risk," Dr O'Meara told ABC News.

"Sexism is alive and well in the Australian screen industry, sometimes blatant, often veiled or subtle."

Dr O'Meara said the data shows that men hold a privileged position in the screen industry that they have not earned.

"The films they write and direct are less commercially successful than those created by women.

"Men are allowed to fail in their creative pursuits — write or direct a film that flops — and are given another chance to prove themselves.

"Women who create a project that flops are condemned and ostracised.

"This is a clear double standard."

Dr O'Meara said government screen agencies could do much more to pursue fairness and stamp out discrimination but are often too closely aligned with the industry to push back on faulty logic.

"Government screen agencies seem quick to celebrate a minor improvement rather than work to address the glacial pace of change.

"This data shows that, even in purely commercial terms, creative women should be sought out and given more chances to create stories and develop careers in the screen industry."