Figure out the one solution - not three - that you want to see happen. There were quite a few things we could have gone after but we decided to focus on the commanders and that was a strategic decision because that, for us, would be the most vulnerable point and the most effective one that could immediately change.

We really want to send the message that commanders need to understand and be accountable. We saw that with the Catholic Church. No one cared when they went after the priests, but when they focused on the bishops then things began to change. And we see that analogy working with the military.

Make sure it is not too diverse or spread out so people don't know where to go or what to do. So keep a sharp focus. It can be ambitious but should have a small agenda.

One of the top challenges is the fact that you are dealing with survivors. Every time you deal with a documentary film subject it is fraught with obvious minefields but when you are dealing with a population that is severely traumatized and trying to recover from that trauma there is an extra level of vigilance and care and attention that has to be implemented all the time at every level.

The difficulty is the levels of secrecy we had to maintain around the project at all different times. We had to keep it a secret while making it so we could move under the radar so we could get the stories. Before it came out we had to keep it on lock down to protect the safety and security of some people who appear in the film.

You always try and make a film that is a letter that will be read and we are so glad that it is being read by the right people in the right place and is inspiring change. It is also gratifying that the survivors are finding it healing and transformative. That's been really great.

[Working with survivors] it's just a whole different level of concern and that is something that was categorically different working on this film than any other project we had done.