I think there is some good data here on how to reduce police violence. A lot of things to please libertarians here. Even though I agree with #4, I do wonder if the research cited quite filtered out cart and horse. I was glad to see that implicit bias was shot down. It is irritating that he has to take a swipe at a president who has initiated reforms rather than those who have talked about it, but these things happen in the research biz. He has a narrow focus, which is appropriate if you are trying to create changes.
For those looking at the larger, human-nature angle here, accountability seems to be key. Very biblical, really.