Workplace violence can be any act of physical violence, threats of physical violence, harassment, intimidation, or other threatening, disruptive behavior that occurs at the work site. Workplace violence can affect or involve employees, visitors, contractors, and family. A number of different actions in the work environment can trigger or cause workplace violence. A Society for Human Resource Management study shows that more than half the companies in the United States have experienced some sort of workplace violence, with verbal threats being cited by 41% of respondents as the most common form. The study also indicated that about 68% of respondents indicated they have a formal workplace violence policy. Workplace violence can be inflicted by an abusive employee, a manager, supervisor, co-worker, customer, family member, or even a stranger.