LOS ANGELES — You watched the wrenching documentary. You posted your outrage on Twitter. But are you good for more than a few easy keystrokes of hashtag activism?

Participant Media and some powerful partners need to know.

For the last year Participant, an activist entertainment company that delivers movies with a message, has been quietly working with the Bill & Melinda Gates Foundation, the Knight Foundation and the University of Southern California’s Annenberg School for Communication and Journalism to answer a question vexing those who would use media to change the world.

That is, what actually gets people moving? Do grant-supported media projects incite change, or are they simply an expensive way of preaching to the choir?

Ultimately, the answers may help determine which projects get financed, which formats are favored and how stories are structured. That could be true for so-called double bottom line companies like Participant, which seek to profit (or at least break even) while creating social change, and also for nonprofits like the Gates Foundation, which increasingly rely on entertainment-style media (like the education documentary “Waiting for ‘Superman’ ”) to drive an agenda.