In January 2015, a surgeon at Brigham and Women’s Hospital in Boston was shot and killed at work by the son of a deceased patient. Even though the event received substantial media coverage, reporters did not highlight the fact that although the murder of a health care worker is rare, episodes of workplace violence against medical providers happen daily across the country.

Although the majority of these incidents of workplace violence are verbal, many others constitute assault, battery, domestic violence, stalking, or sexual harassment.1
This review focuses on our current knowledge about workplace violence in various health care settings, including the prevalence across professions, potential risk factors, and the use of metal detectors in preventing violence. It also highlights the difficulty researchers have encountered in developing experimental models and the need for further evidence-based research.
Health care workplace violence is an underreported, ubiquitous, and persistent problem that has been tolerated and largely ignored. According to the Joint Commission, a major accrediting body for health care organizations, institutions that were once considered to be safe havens are now confronting “steadily increasing rates of crime, including violent crimes such as assault, rape, and homicide.”2 Even though the health care sector is statistically among the industries most subject to violence in the United States (aside from law enforcement),3 researchers have yet to discover statistically significant, universally applicable methods of risk reduction. To date, most research has been directed at quantifying the problem and attempting to profile perpetrators and their victims. The few studies that have focused on interventions to reduce violence have highlighted the unlikelihood of finding a simple, one-size-fits-all solution to prevent this violence.
Experts have classified workplace violence into four types on the basis of the relationship between the perpetrator and the workplace itself (Table 1TABLE 1Types of Workplace Violence.). Most common to the health care setting is a situation in which the perpetrator has a legitimate relationship with the business and becomes violent while being served by the business (categorized as a type II assault).4,5 The highest number of such assaults in U.S. workplaces each year are directed against health care workers.1 These episodes are characterized by either verbal or physical assaults perpetrated by patients and visitors against providers. Although other types of workplace violence certainly deserve attention, in a 2014 survey on hospital crime, type II workplace violence accounted for 75% of aggravated assaults and 93% of all assaults against employees.6
Among episodes of fatal violence against employed adults, nearly 25% occur at their place of employment.3 Between 2011 and 2013, the number of workplace assaults averaged approximately 24,000 annually, with nearly 75% occurring in health care settings.7 Data from the Bureau of Labor Statistics show that health care workers are nearly four times as likely to require time away from work as a result of violence as they are because of other types of injury.8
However, inconsistencies in the existing data can make interpretation of the findings quite difficult. The Bureau of Labor Statistics and the National Institute for Occupational Safety and Health are among several federal agencies devoted to the collection of statistics on workplace violence, and their results are disparate. The results of academic studies also vary considerably. In addition, inconsistency in defining categories of violence (e.g., verbal assault, threats, physical assault, and battery) compromise reliability among studies.9-13 One review showed that no two studies have used the same instrument to measure workplace violence in the emergency department,13 and nearly every study method was based on voluntary retrospective surveys, an approach that risks both selection bias and recall bias. Furthermore, data from the federal Bureau of Labor Statistics may be grossly inaccurate,14,15 as shown by one study in which investigators found that the actual number of reportable injuries was as much as three times the number in the federal survey.16 Since the Bureau of Labor Statistics does not record verbal incidents, the prevalence of workplace violence cannot be reliably gauged on the basis of data from the agency.17 Despite these limitations, the statistics on the prevalence of workplace violence in the health care setting remain alarming.
Most studies on workplace violence have been designed to quantify the problem, and few have described research on experimental methods to prevent such violence. The most recent critical review of the literature in 2000 identified 137 studies that described strategies to reduce workplace violence. Of these studies, 41 suggested specific interventions, but none provided empirical data showing whether or how such strategies worked. Only 9 studies, all of which were health care–related, reported data on interventions. Even so, the conclusion of the 9-study review was that each of the studies used weak methods, had inconclusive results, and used flawed experimental designs.18 A review of nursing literature had similar conclusions: all the studies showed that after training, nurses had increased confidence and knowledge about risk factors, but no change was seen in the incidence of violence perpetrated by patients. There is a lack of high-quality research, and existing training does not appear to reduce rates of workplace violence.