The City Council of Berkeley, California, is currently considering a request by the city's police department to allow officers to carry and use Tasers, a practice adopted by more than 12,000 police departments across the country in recent years that has quickly made the electronic weapon a source of controversy.
The council asked Stanford Law School's Criminal Justice Center to study the effectiveness and safety of Tasers and other "electronic control weapons" ahead of their decision, resulting in a report released this week that questions many of the claims that have bolstered the popularity of such shock devices in recent years, including their ability to minimize the use of lethal force by officers.
The Bureau of Justice Statistics reports that as of 2013, the last year for which data is publicly available, 81 percent of local police departments in the US used electronic control weapons. Meanwhile, a study by Amnesty International found that more than 500 Taser-related deaths occurred in the United States between 2001 and 2012.
Stanford's Criminal Justice Center analyzed more than 150 studies that have been conducted on the use of such weapons, and determined that many of the claims about their safety and ability to reduce confrontations were not as clear-cut as has been widely accepted or portrayed.
Among the Stanford report's major findings were that the weapons have been found to be safe when used in the right circumstances but that they are most frequently used outside of those parameters, including when subjects are under the influence of drugs or alcohol or have mental or physical handicaps. The authors also found that while Tasers do generally reduce injuries to officers, it is unclear whether the same can be said for suspects. They noted that minor Taser injuries — in which the skin is pierced with barbs that have to be medically removed — are frequently omitted when compiling data.
In all, the researchers concluded that many studies on the use of these devices have been limited, and found no clear evidence that their use reduces lethal force.
"Our own conclusion is that, while the literature suggests that [electronic control weapons] may have benefits, these benefits are easily overstated," the authors write. "Moreover, realizing those potential benefits — such as reducing the rate of injuries to officers and possibly suspects — may require accepting the possibility that vulnerable populations are more likely to be exposed to the painful effects of [electronic control weapons]."
Akiva Freidlin, one of the report's co-authors, said that Berkeley officials asked the team to help analyze the evidence they could find to determine whether Tasers really were effective and safe. The report does not make specific recommendations for the city, but it amounts to a cautious warning about their adoption.
"The way I would sum up the conclusion now is that there are so many gray areas," he remarked. "I kind of see it as there's nothing in the research that's going to make it an obvious yes or no, but the way we read that the research has been done really undercuts or complicates the case in favor of adopting them."
Freidlin explained that many of the claims about Tasers and other devices reducing or replacing use of force incidents and reducing injuries to suspects had become "common wisdom" because of an echo chamber effect in which the claims were continually touted among different law enforcement groups, and because it is hard to find good data on their use when it requires obtaining thousands of reports from many different jurisdictions.
The research team's realization that many studies omitted minor injuries from their reports was particularly enlightening, he added.
"So, okay, that doesn't mean people are dying left and right from these — though that happens, particularly when it intersects with populations who get in confrontations with police officers, like those using drugs and alcohol and with mental and physical issues," Freidlin said. "But what we're saying after looking at all this is that the claim that this reduces risk to suspects is hand-waving away what to most people would be considered some kind of injury."
Taser International, the company that manufactures the weapon, did not respond to requests for comment. It has previously pointed to a 2011 Department of Justice study on the safety of Tasers in which "an expert panel of medical professionals concludes that the use of conducted energy devices by police officers on healthy adults does not present a high risk of death or serious injury."
Freidlin and his fellow researchers largely relied on that study in their report. He said that the key phrase is "healthy adults," pointing out that the study found no high risk of injury or death in "healthy, non-stressed, non-intoxicated" individuals — which aren't typically the people on which police use their Tasers. The Stanford report refers to a comprehensive review published in 2011 which found that "the majority of subjects exposed to a Taser were under the influence of alcohol or illicit drugs or had psychiatric comorbidities."
"We don't maintain that there's a tremendous risk of death in most cases—probably even in the vast majority of cases," he said. "But researchers cannot ethically study the impact of ECWs on those individuals for whom the risks are highest and least understood. "
In light of this, the Stanford researchers believe it's important that the DOJ study not be reduced to a simple affirmation of proof that weapons like Tasers are safe.
"Any careful weighing of the costs and benefits of [electronic control weapon] use must to take that risk or uncertainty into account," Friedlin said.
Berkeley Police Chief Michael Meehan is asking the council to grant his department permission to use Tasers despite the misgivings of the report's authors.
"The combined body of evidence and decades-long experience leads me to believe that the availability of [electronic control weapons] is in the best interests of our employees and our community," Meehan said. "I would not say this if I did not think it was in the best interests of both."
The council has not yet voted on the matter.
Follow Colleen Curry on Twitter: @currycolleen