Study Finds Misconduct Spreads Among Police Officers Like Contagion

According to new research, reassigning police officers with a history of misconduct makes it more likely that their new peers will also misbehave.

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Behaviors—both good and bad—can spread between peers in any environment, including the police force. Image Credit: kali9, iStock

Nearly five years after fatally shooting 17-year-old Laquan McDonald in October 2014, former Chicago police officer Jason Van Dyke is now serving a seven-year prison sentence on a conviction of second-degree murder.

But firing 16 bullets at a black teenager holding a knife was likely far from Van Dyke’s first offense. Since he began policing in 2001, at least 25 separate complaints have been filed against Van Dyke by civilians and fellow officers, most involving excessive force. Prior to the most recent charges, none of these allegations resulted in disciplinary action, leaving Van Dyke in the employ of the Chicago Police Department until he was stripped of the position during indictments.

Van Dyke’s case is extreme. But his trajectory wasn’t anomalous. Rather than being fired, officers accused of stealing, lying, mistreating civilians, or otherwise abusing their power are often allowed to retain their roles as public servants, with some rerouted into new positions in the force as a reprimand for bad behavior.

Now, new research published today in the journal Nature Human Behavior suggests that retaining misbehaving officers in police organizations might have far worse consequences than leaving accusations unaddressed: It could actually propagatemisconduct itself.

Even the well-intended shuffle of reassignment, often doled out in attempt to stem the transgressions of offending officers, could be having the exact opposite effect, spreading misdeeds from individuals to their peers like a behavioral contagion.

“I’m really happy to see this study, because it’s very hard to do research on this topic,” says Carol Archbold, a criminologist studying police accountability at North Dakota State University who was not involved in the study. “This shows that it’s important to have accountability in place to track and identify these officers. If you don’t correct the problematic behavior, you’re just moving the problem.”

These findings confirm what’s been hinted at by prior research, including work that has focused on police misconduct in the United States. Most older studies, however, relied on data collected from surveys and interviews of police officers, making it tough to tell if patterns of misconduct were a result of the ripple effect of peer-to-peer influence, or if individuals simply choose to associate with peers with similar inclinations.

The new study, however, took an unprecedented approach. To construct an effective timeline of officers’ actions, behavioral economists Edika Quispe-Torreblanca and Neil Stewart leveraged four years of records from the London Metropolitan Police Service, analyzing data from 35,000 individual police personnel between 2011 and 2014. As officers moved from appointment to appointment, the researchers tabulated allegations of misconduct levied against them and their coworkers (a common proxy for misconduct in these types of studies). Unlike its predecessors, the study could pinpoint instances in which the track records of a misbehaving officer’s new peers took a downturn after that person came onto the scene—changes that hinted strongly at cause and effect.

“The [authors] were able to get rid of many of the issues that other research faces,” says Ojmarrh Mitchell, a criminologist at the University of South Florida who authored a commentary on the new study. “[These results] indicate a causal relationship, and that’s a remarkable finding.”

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Studies have shown that a small fraction of police officers are responsible for a disproportionate number of acts of misconduct. Image Credit: ChiccoDodiFC, iStock

The new study found that, as officers with records of misconduct transitioned between working groups within the police force, they consistently increased the likelihood that those around them would be accused of bad behavior.

This wasn’t very surprising, Stewart says. But no one had ever put an exact number to how strong these effects were—and even he and Quispe-Torreblanca were taken aback by its magnitude: For every 10 percent increase in the proportion of a police officer’s peers with a history of misconduct (for instance, adding one allegedly misbehaving member to a group of 10), that officer’s chances of engaging in misdeeds in the next three months rose by nearly 8 percent.

“Given how frequently police officers are transferred to different units in response to bad behavior, this contagion effect is really important,” Mitchell says.

The effect is also likely not restricted to wayfaring officers in transition: Though more difficult to measure, bad behavior probably also disseminates within existing groups, Stewart says.

What’s not yet clear, however, is the root of the infectious nature of police misconduct. But this is far from the first study to find that our peers hold serious sway over our actions under a variety of circumstances. “I don’t think this is a police problem as much as a human being problem,” Stewart says.

And humans tend to look to the people around them for guidance on how to behave. “We are a social species, and fitting in with a group is just a very powerful part of our nature,” says Linda Treviño, an expert in organizational behavior and ethics at Pennsylvania State University who was not involved in the study. “If everyone in a social context is doing things in a particular way, ethical or unethical, most people will follow their lead.”

Addressing the issue will likely require interventions on multiple fronts, Mitchell says. One solution might include improving methods of identifying and disciplining (and not reassigning) a small faction of particularly problematic officers in the force who are responsible for a disproportionately large share of police misconduct—and might be repeatedly seeding bad behavior in others. In spite of evidence that bad behavior often concentrates in a minority of corrupt cops, few officers are disciplined or fired in the aftermath of misconduct. Even among those who are terminated, some quickly end up rehired in other jurisdictions, potentially widening their reach.

“Bad officers stick around for much longer than they should,” Mitchell says. “Removal needs to be easier than it has been.”

But the larger issue at hand might be cultural, Treviño says. If police organizations as a whole remain tolerant of misconduct, these issues are unlikely to get resolved anytime soon. “Managers need to look at the entire system that is creating the social environment that supports the bad behavior,” she says. “It’s about the context you create…if there’s leadership that says, ‘We have values, this is the way we behave, this is what the expectations are,’ if a toxic person comes along, they’ll get spit out.”

Part of this overhaul might require rethinking the infamous “code of silence” that prevails among law enforcement officers, many of whom have been accused of turning a blind eye to crooked behavior amongst colleagues in the field in an effort to preserve camaraderie. Those violating the code have suffered serious repercussions, including, perhaps most infamously, Frank Serpico, who was ostracized and abandoned by his fellow police officers after whistleblowing on the NYPD’s rampant corruption in 1971.

“Police executives need to foster an environment that encourages officers to say something if they see something,” Archbold says. “It really begins and ends with encouraging officers to report…and making officers feel supported by peers and supervisors if they do.”

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Many officers maintain clean records. But for those who misbehave, there aren’t always consequences. Between 1975 and 1996, for instance, less than 2 percent of NYPD officers were terminated for misconduct. Image Credit: Travel Wild, iStock

Simply building and maintaining archives like the one analyzed in the new study, however, could increase accountability, Archbold says. Though similar compilations haven’t traditionally been common in the United States, a nationwide effort by the USA TODAY Network recently identified more than 85,000 law enforcement officerswho have been investigated or disciplined for acts of misconduct over the last decade—a “treasure trove” of data that could yield powerful follow-up research in the future, she adds.

On a smaller scale, early intervention systems that enable organizations to monitor problematic behavior could flag officers who might benefit from immediate retraining, counseling, and supervision, Archbold says. “The spread [of misconduct] can be stopped if it’s tracked, and if something’s done about it.”

In the meantime, it’s worth keeping in mind how many working members of the police force maintain clean records, Stewart says. The contagiousness of behavior remains a two-way street. There’s nothing to say that ethical attitudes aren’t transmitted between peers, too—or even that negative effects are irreversible. In their analysis, the researchers also found that when the number of deviant officers in a cohort went down, so did the chances of its remaining members engaging in misconduct.

In other words, an antidote does exist—one that’s capable of tempering the malady, even as it spreads.

“Peer effects work both ways,” Treviño says. “A strong, ethical social environment is a very powerful positive tool.”


KATHERINE J. WU, “Study Finds Misconduct Spreads Among Police Officers Like Contagion”,


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