Documentary writer Mark Monroe has developed such Oscar-winning films as ICARUS and THE COVE. He walks through how he uses test screenings to understand an audience's experience of a film and how to then make adjustments to deliver the strongest story.
As a filmmaker, you are emotionally attached to your story. An audience doesn’t have your same experience of making the film, so you need their fresh perspective to see where the story gets confusing, where energy drops, or elements of the storytelling aren’t working.
Every creative decision improves or hurts your film. Once you send an audience down a path, they stay there until you change the direction. You always want to know when and why your audience disengages with your film.
As the filmmaker, you are building the world and the rules of the world for an audience. These boundaries must be clear so an audience tracks the story in the way you intend.
Test screenings negate opinion. Although the director and creative team will all have opinions, you need the unbiased data from an audience to make informed creative decisions.
Your lived experience of making the film is not what will impact an audience. Your role as a filmmaker is to distill and structure the emotional journey of the story and characters, and put that on the screen, so a broad audience can be invested.