Documentary film has a stronger track record of impact than almost any other narrative form. When a documentary works, it combines the emotional engagement of narrative with the authority of fact, creating a perspective shift that dry journalism rarely achieves.
Super Size Me (2004) is the canonical example of documentary impact. Morgan Spurlock's month of McDonald's eating — regardless of its scientific limitations — created a cultural moment that genuinely shifted fast food marketing and nutritional disclosure practices. McDonald's discontinued the Supersize option the same year the film released. Whatever the film's methodological weaknesses, it moved the real world.
Blackfish (2013) documented the treatment of orca whales at SeaWorld and catalyzed a significant behavioral change from the attending public and the company's own investors. SeaWorld stock fell 33% in the year following the film's release on Netflix. The company eventually announced it would end theatrical orca performances.
The films that change minds most effectively share a structural quality: they present evidence that allows viewers to arrive at the conclusion themselves, rather than stating the conclusion and then arguing for it. Viewers who feel they've discovered something are more committed to the insight than viewers who feel they've been lectured to.
For documentaries with outstanding production quality combined with genuine impact: 13th (American incarceration system), Seaspiracy (ocean fishing industry), The Dig (archaeological discovery and institutional power), and Won't You Be My Neighbor? (the value of genuine kindness in public media).
Watch with critical attention: all documentaries make editorial choices. The absence of counterarguments doesn't mean they don't exist.