"Long before it's in the papers"
January 27, 2015


Study finds police body-cameras can prevent violence

Dec. 26, 2014
Courtesy of the University of Cambridge
and World Science staff

Body cam­er­as on po­lice of­fi­cers may re­duce abu­sive be­hav­ior both by and against of­fi­cers, a study has found.

Re­search­ers from the Uni­vers­ity of Cam­bridge in the U.K. pub­lished the re­sults of an ex­pe­ri­ment they con­ducted on the cameras’ ef­fects in Ri­al­to, Ca­lif. in 2012. The year-long study found that use of force by cam­er­a-wearing po­lice fell by 59 per­cent and re­ports against of­fi­cers dropped by 87 per­cent against the pre­vi­ous year’s fig­ures.

A body-worn police camera. Re­search­ers from the Uni­vers­ity of Cam­bridge in the U.K. pub­lished the re­sults of an ex­pe­ri­ment they con­ducted on polic­ing with body-worn-cam­er­as in Ri­al­to, Ca­lif. in 2012. (Image courtesy  voa.gov)

While the tech­nol­o­gy helps cap­ture ev­i­dence for po­ten­tial use in court, its great­est ben­e­fit may be pre­vent­ing es­cala­t­ion to vi­o­lence in the first place, the in­ves­ti­ga­tors said—in short, peo­ple tend to be­have when they know they’re on cam­era.

How­ev­er, the re­search team cau­tion that the Ri­al­to ex­pe­ri­ment is only a first step, and that more needs to be known about the im­pact of body-worn cam­er­as be­fore po­lice de­part­ments are pres­sured in­to adopt­ing the tech­nol­o­gy.

Vi­tal ques­tions re­main, they ex­plained, about how rou­tine pro­vi­sion of dig­it­al vi­deo as ev­i­dence will af­fect pros­e­cu­tion ex­pecta­t­ions, and the stor­age tech­nol­o­gy and poli­cies that the im­mense amounts of new da­ta will re­quire. Pres­ident Obama re­cently prom­ised to spend $75 mil­lion of fed­er­al funds on body-worn-vi­deo to ad­dress per­sist­ent protests over po­lice kill­ing un­armed black men.

Some ques­tion the mer­it of cam­era tech­nol­o­gy giv­en that the of­fic­er re­spon­si­ble for kill­ing Er­ic Gar­ner—a 43-year-old black man suf­fo­cat­ed dur­ing ar­rest for sell­ing un­taxed cigarettes—was ac­quit­ted by a grand ju­ry even though a by­stand­er filmed the al­terca­t­ion on a cell phone. Foot­age showed an il­le­gal ‘choke­hold’ placed on Gar­ner who re­peat­edly states: “I can’t breathe.” (A med­i­cal ex­am­in­er ruled the death a homi­cide).

For the Cam­bridge re­search­ers, the Ri­al­to re­sults show that body-worn-cam­er­as can re­duce the need for such ev­i­dence by pre­vent­ing ex­ces­sive force in the first place.

“In the trag­ic case of Er­ic Gar­ner, po­lice weren’t aware of the cam­era and did­n’t have to tell the sus­pect that he, and there­fore they, were be­ing filmed,” said Bar­ak Ar­i­el of Cam­bridge’s In­sti­tute of Crim­i­nol­o­gy, who con­ducted the ex­pe­ri­ment with Cam­bridge col­league Al­ex Suth­er­land and Ri­al­to po­lice chief Tony Far­rar.

“With in­sti­tu­tion­al body-worn-cam­era use, an of­fic­er is obliged to is­sue a warn­ing from the start that an en­coun­ter is be­ing filmed, im­pacting the psy­che of all in­volved by con­vey­ing a straight­for­ward, prag­mat­ic mes­sage: we are all be­ing watched, vid­e­otaped and ex­pected to fol­low the rules,” he said.

The idea be­hind body-worn-vid­e­o, in which small high-definition cam­er­as are strapped to a po­lice of­fi­cers’ tor­so or hat, is that eve­ry step of eve­ry po­lice-public in­ter­ac­tion—from the mun­dane to those in­volv­ing deadly force—gets recorded to cap­ture the clos­est ap­proxima­t­ion of ac­tu­al events for ev­i­dence pur­poses, with only case-relevant da­ta be­ing stored.

In Ri­al­to, po­lice shifts over the course of a year were ran­domly as­signed to be ei­ther with or without camera, with video covering over 50,000 hours of in­ter­ac­tions. Ar­i­el and col­leagues are repli­cat­ing the Ri­al­to ex­pe­ri­ment with over 30 forc­es across the world, and early signs match the Ri­al­to suc­cess, Ariel said.

Bod­y-worn cam­er­as seem very cost-ef­fec­tive: anal­y­sis from Ri­al­to showed eve­ry dol­lar spent on the tech­nol­o­gy saved about four dol­lars on com­plaints litiga­t­ions, the re­search­ers added. But with tech­nol­o­gy be­com­ing cheaper, the sheer vol­umes of da­ta stor­age could be­come crip­pling.

“User li­censes, stor­age space, ‘se­cur­ity costs’, main­te­nance and sys­tem up­grades can po­ten­tially trans­late in­to bil­lions of dol­lars world­wide,” Ar­i­el said.

And, if body-worn cam­er­as be­come the norm, what might the cost be when vi­deo ev­i­dence is­n’t avail­a­ble? “His­toric­ally, court­room tes­ti­monies of re­sponse of­fi­cers have car­ried tre­men­dous weight, but prev­a­lence of vi­deo might lead to re­luc­tance to pros­e­cute when there is no ev­i­dence from body-worn-cam­er­as to cor­rob­o­rate the tes­ti­mo­ny of an of­fic­er, or even a vic­tim,” said Ar­i­el.

The study is pub­lished in the Jour­nal of Quanti­tative Crim­i­nol­o­gy.

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Body cameras on police officers may reduce abusive behavior both by and against officers, a study has found. Researchers from the University of Cambridge in the U.K. published the results of an experiment they conducted on policing with body-worn-cameras in Rialto, Calif. in 2012. The year-long study found that use of force by camera-wearing officers fell by 59% and reports against officers dropped by 87% against the previous year’s figures. While the technology helps capture evidence for potential use in court, its greatest benefit may be preventing escalation to violence in the first place, the investigators said—in short, people tend to behave when they know they’re on camera. However, the research team caution that the Rialto experiment is only a first step, and that more needs to be known about the impact of body-worn cameras before police departments are pressured into adopting the technology. Vital questions remain, they explained, about how routine provision of digital video as evidence will affect prosecution expectations, and the storage technology and policies that the immense amounts of new data will require. President Obama recently promised to spend $75 million of federal funds on body-worn-video to address persistent protests over police killing unarmed black men. Some question the merit of camera technology given that the officer responsible for killing Eric Garner—a 43-year-old black man suffocated during arrest for selling untaxed cigarettes—was acquitted by a grand jury even though a bystander filmed the altercation on a cell phone, with footage showing an illegal ‘chokehold’ administered on Garner who repeatedly states: “I can’t breathe.” (A medical examiner ruled the death a homicide). For the Cambridge researchers, the Rialto results show that body-worn-cameras can reduce the need for such evidence by preventing excessive use-of-force in the first place. “In the tragic case of Eric Garner, police weren’t aware of the camera and didn’t have to tell the suspect that he, and therefore they, were being filmed,” said Barak Ariel of Cambridge’s Institute of Criminology, who conducted the experiment with Cambridge colleague Alex Sutherland and Rialto police chief Tony Farrar. “With institutionalized body-worn-camera use, an officer is obliged to issue a warning from the start that an encounter is being filmed, impacting the psyche of all involved by conveying a straightforward, pragmatic message: we are all being watched, videotaped and expected to follow the rules,” he said. The idea behind body-worn-video, in which small high-definition cameras are strapped to a police officers’ torso or hat, is that every step of every police-public interaction—from the mundane to those involving deadly force—gets recorded to capture the closest approximation of actual events for evidence purposes, with only case-relevant data being stored. In Rialto, an experimental model was defined in which all police shifts over the course of a year were randomly assigned to be either experimental (with camera) or control (without camera), encompassing over 50,000 hours of police-public interactions. Ariel and colleagues are replicating the Rialto experiment with over 30 forces across the world. Early signs match the Rialto success, they said. Body-worn cameras appear to be highly cost-effective: analysis from Rialto showed every dollar spent on the technology saved about four dollars on complaints litigations, the researchers added. But with technology becoming cheaper, the sheer volumes of data storage could become crippling. “User licenses, storage space, ‘security costs’, maintenance and system upgrades can potentially translate into billions of dollars worldwide,” Ariel said. And, if body-worn cameras become the norm, what might the cost be when video evidence isn’t available? “Historically, courtroom testimonies of response officers have carried tremendous weight, but prevalence of video might lead to reluctance to prosecute when there is no evidence from body-worn-cameras to corroborate the testimony of an officer, or even a victim,” said Ariel. The study is published in the Journal of Quantitative Criminology.