Dr. Peter Ejbye-Ernst defended his PhD thesis entitled Intervention in (Inter)Action: A video-based analysis of the role of third parties in interpersonal conflicts at the Universiteit van Amsterdam April 13th.
Peter's research shows that the way that people intervene is influenced by the gender of the people fighting, the severity of the situation, their own past behaviors in the situation, and if they know any of the involved parties. His findings indicate that stopping a fight is rarely an easy task but rather requires persistence and a willingness to physically involve yourself. While this project can’t tell if someone should take action or not, it does point towards what is needed if you want to be successful in trying to stop a conflict from escalating further: you have to be decisive and persistent.
His thesis can be read here