I agree with the Workplace Bullying Institute that mediation is not a tool that works well, if at all, in bullying type of problems. Why? Because there is either an implicit or explicit power differential. That is either the aggressor is using emotional abuse or structural power to overtake the target. Those conditions don’t disappear when a mediator arrives. Mediation implies that both parties are wrong and there is something to settle between the two parties. But workplace aggression isn’t about misunderstandings or mutual blame or settling a financial dispute. Workplace aggression is a complex combination of psychological factors, structural conditions, and power differences. A good executive coach who is skilled at handling aggression among people can sort through the circumstances and offer solutions. Be sure the coach is sophisticated enough to make referrals for psychological counseling, where needed, is able to uncover the structural problems (corporate culture and mores, quality of supervision, degree of accountability on both performance and behavior, team functionality, etc.) and then propose strategies to fix them.
Workplace aggression is more than a simple mis-understanding, and more complicated than a simple power differential.
Here’s more info and insights into workplace conflict, aggression and bullying and whether or not mediation helps: Workplace Bullying Institute