Regarding persuasion, it's best to use an audience's pre-existing beliefs.
This is opposed to the idea of altering their beliefs, or trying to convince people of a new belief.
Of course, this idea isn't 100%.
But many studies in the field of perception management reveal that the manipulation of people's pre-existing beliefs will achieve greater results in regards to mass persuasion.
What does this have to do
with documentary filmmaking?
Well, documentaries are based on the real world.
There's a presumption of reality occurring with the frame of the narrative.
What happens in front of the camera exists in the same reality as we do (unlike fiction).
This makes the ideas, facts, and philosophies of a documentary tactile to every viewer who watches them.
Meaning, they can put these ideas to work or incorporate them into their own general knowledge of the world.
Documentaries deal in factual records or reports.
And, often, they have an agenda.
You will likely have an agenda while making your movie.
So having the most cutting-edge methods of information dissemination and arrangement will help your movie have an edge over others of a similar subject.
In the Information Age,
the ability to manage your movie's perception
will be vital.
So if you're trying to persuade an audience of something new, start off by USING what they already believe in.
For example, Dinesh D'Souza in his film "2016: Obama's America" - he uses a certain audience's deeply held fear about President Obama to gain attention toward the movie.
I mean, how rare is it that a documentary gets played in theaters in the first place?
So Mr. D'Souza used those pre-existing beliefs to hype the film.
Then, he amplified and steered these pre-existing beliefs toward his own unique conclusion.
This is perception management.
Likewise, on the other side of the political spectrum, Michael Moore in his film "Bowling for Columbine" uses a certain audience's deeply held beliefs about gun control to hype his own agenda.
The movie is filled with stereotypes of gun-loving Southern nuts, and cool-headed liberal intellectuals denouncing gun culture.
All of these ideas are very familiar, and already existing, within the audience of the movie.
Yet, Mr. Moore amplifies and steers these beliefs toward his own unique conclusions.
So for the greatest reward: Instead of the more complex process of trying to alter pre-existing beliefs by presenting false evidence, try steering people's already existing beliefs toward your own agenda.