Okay, Fairweather. I went and read the report. In all eleven cases for intervention to prevent violence, the outcome was the same, "insufficient evidence to determine outcome". This means they couldn't tell one way or the other for a variety of reasons ranging from lack of studies, lack of necessary records, inconsistent results, etc. This is not the same thing as "no cause and effect" as you put it. Did anyone go read that report? Personally, I think that panel was afraid to reach a conclusion for fear of the backlash that would inevitably ensue.