My experience so far as a parent is that there is no such thing as universally appropriate parenting technique. Every child has their own personality and responds to different things in different ways.

Still, I prefer to use techniques that don't make my children feel unhappy, for obvious reasons. First the carrot, then the stick.

People indicate the methods from that book saved their marriages. I’m not aware of any studies because I don’t have time to become an expert on this. Violence comes in many forms and diminishes peoples’ autonomy. That’s almost the definition of violence. So remove the diminishing language as a start.