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PERmIT NO. G–91

2011 MAY

NCJ 232215

*NCJ~232215*

 

   

  

 

 

 
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U.S. Department of Justice 

Office of Justice Programs 

810 Seventh Street N.W. 

Washington, DC 20531 

Eric H. Holder, Jr. 

Attorney General 

Laurie O. Robinson 

Assistant Attorney General 

John H. Laub 

Director, National Institute of Justice 
 

 

 

 

 

 

 

 

 

May 2011 

Police Use of Force, Tasers and Other 

Less-Lethal Weapons 

Findings and conclusions of the research reported here are those of the 

authors and do not necessarily reflect the official positions or policies of the 

U.S. Department of Justice. 

This Research in Brief is based primarily on “A Multi-Method Evaluation 

of Police Use of Force Outcomes,” final report to the National Institute of 

Justice, July 2010, NCJ 231176, available online at http://www.ncjrs.gov/ 

pdffiles1/nij/grants/231176.pdf. 

This research was supported by grant number 2005–IJ–CX–0056 from the 

National Institute of Justice. 

NCJ 232215 
ii 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

About this report 

This study looked at injuries 

that occur to law enforcement officers and citizens 

during use-of-force events. 

Most applications of force 

are minimal, with officers 

using their hands, arms or 

bodies to push or pull against 

a suspect to gain control. 

Officers are also trained 

to use various other force 

techniques and weapons to 

overcome resistance. These 

include less-lethal weapons 

such as pepper spray, batons 

or conducted energy devices 

(CEDs) such as Tasers. They 

can also use firearms to 

defend themselves or others 

against threats of death or 

serious bodily injuries. 

What did the 

researchers find? 

This study found that when 

officers used force, injury 

rates to citizens ranged from 

17 to 64 percent, depending 

on the agency, while officer 

injury rates ranged from 10 

to 20 percent. Most injuries 

involve minor bruises, strains 

and abrasions. 

The study’s most significant 

finding is that, while results 

were not uniform across all 

agencies, the use of pepper spray and CEDs can 

significantly reduce injuries 

to suspects and the use of 

CEDs can decrease injuries 

to officers. 

The researchers assert that 

all injuries must be taken seriously. When police in a democracy use force and injury 

results, concern about police 

abuse arises, lawsuits often 

follow and the reputation 

of the police is threatened. 

Injuries also cost money in 

medical bills for indigent suspects, workers’ compensation claims for injured officers 

or damages paid out in legal 

settlements or judgments. 

What were the study’s 

limitations? 

In many cases, agencysupplied injury data did not 

allow for a detailed analysis 

of the nature or seriousness 

of the injuries reported. 
1 

P o l I C E U S E o F F o R C E 

 

 

Geoffrey P. Alpert, Michael R. Smith, Robert J. Kaminski, 

Lorie A. Fridell, John MacDonald, and Bruce Kubu 

police use of Force, tasers and 

other Less-Lethal Weapons 

About the Authors 

Geoffrey P. Alpert, 

Ph.D., is professor of 

criminology and criminal 

justice at the University 

of South Carolina. 

Michael R. Smith, J.D., 

Ph.D., is professor of 

political science and 

dean of the College of 

Liberal Arts and Social 

Sciences at Georgia 

Southern University. 

Robert J. Kaminski, Ph.D., 

is associate professor of 

criminology and criminal 

justice at the University of 

South Carolina. Lorie A. 

Fridell, Ph.D., is associate 

professor of criminology 

at the University of 

South Florida. John 

MacDonald is associate 

professor of criminology 

at the University of 

Pennsylvania. Bruce 

Kubu is senior research 

associate at the Police 

Executive Research 

Forum. 

introduction 

Police weaponry has come 

full circle. 

During the middle of the 

19th century, police officers 

in New York and Boston 

relied on less-lethal weapons, 

mostly wooden clubs. By late 

in the century, police departments began issuing firearms 

to officers in response to better armed criminals. Although 

firearms are still standard 

issue, law enforcement agencies are again stressing the 

use of less-lethal weapons 

rather than firearms.1 

The Fourth Amendment forbids unreasonable searches 

and seizures, and various 

other legal and policy controls govern how and when 

officers can use force. Most 

agencies tightly control the 

use of force and supervisors or internal affairs units 

routinely review serious 

incidents. New technologies 

have added to the concerns 

about the use of force by law 

enforcement. 

New technologies 

raise questions 

During the past 20 years, 

new technologies have 

emerged that offer the 

promise of more effective 

control over resistive suspects with fewer or less 

serious injuries. Pepper spray 

was among the first of these 

newer less-lethal weapons to 

achieve widespread adoption 

by police forces, and more 

recently, conducted energy 

devices (CEDs) such as the 

Taser have become popular. 

Taser use has increased 

in recent years. More than 

15,000 law enforcement and 

military agencies use them. 

Tasers have caused controversy (as did pepper spray) 

and have been associated 

with in-custody deaths and 

allegations of overuse and 

intentional abuse. Organizations such as Amnesty 

International and the American Civil Liberties Union have 

questioned whether Tasers 

can be used safely, and what 

role their use plays in injuries 

and in-custody deaths. 
2 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

Several studies 

found that 

when agencies 

adopted the 

use of pepper 

spray, they 

subsequently 

had large 

declines in 

assaults on 

officers and 

declines in 

officer and 

suspect injury 

rates, and 

associated 

injuries were 

usually minor. 

Pepper spray 

provides a 

way to reduce 

injuries. 

CEDs such as Tasers produce 50,000 volts of electricity. The electricity stuns and 

temporarily disables people 

by causing involuntary muscle contractions. This makes 

people easier to arrest or 

subdue. When CEDs cause 

involuntary muscle contractions, the contractions cause 

people to fall. Some people 

have experienced serious 

head injuries or bone breaks 

from the falls, and at least 

six deaths have occurred 

because of head injuries suffered during falls following 

CED exposure. More than 

200 Americans have died after being shocked by Tasers. 

Some were normal, healthy 

adults; others were chemically dependent or had heart 

disease or mental illness.2 

Tasers use compressed nitrogen to fire two barbed probes 

(which are sometimes called 

darts) at suspects. Electricity travels along thin wires 

attached to the probes. (A 

new wireless Taser is also on 

the market.) Darts may cause 

puncture wounds or burns. A 

puncture wound to the eye 

could cause blindness.3 

Despite the dangers, most 

CED shocks produce no serious injuries. A study by Wake 

Forest University researchers 

found that 99.7 percent of 

people who were shocked by 

CEDs suffered no injuries or 

minor injuries only. A small 

number suffered significant 

and potentially lethal injuries. 

This NIJ-sponsored study 

included six police departments and evaluated the 

results of 962 “real world” 

CED uses. Skin punctures 

from CED probes were 

common, accounting for 83 

percent of mild injuries.4 

Policymakers and law enforcement officials want to 

know whether Tasers are 

safe and effective, and how 

(if at all) they should be used 

to match police use-of-force 

choices with levels of suspect resistance. This study 

indicates that CED use actually decreases the likelihood 

of suspect injury. 

previous research 

on use of force and 

injuries 

The controversy around 

Taser use is not unique. Law 

enforcement agencies found 

themselves in similar circumstances with pepper spray 

in the 1990s. Human rights 

groups such as Amnesty 

International questioned the 

safety and misuse of pepper 

spray as its use spread 

rapidly in American law 

enforcement agencies. NIJ 
3 

P o l I C E U S E o F F o R C E 

funded various studies on the 

safety and effectiveness of 

pepper spray.5 

Some studies have focused 

on officer injury. Several 

found that about 10 percent 

of officers were injured when 

force was used.

6

 However, 

two studies of major police 

departments found officer 

injury rates of 38 and 25 

percent.

7

 The agencies with 

lower rates allowed officers 

to use pepper spray, while 

the two with higher rates 

did not. 

A few researchers have 

looked at how various approaches to force affect officer injury rates.8

 Overall, the 

empirical evidence shows 

that getting close to suspects to use hands-on tactics 

increases the likelihood of 

officer injuries. Research also 

shows that suspects have 

a higher likelihood of injury 

when officers use canines, 

bodily force or impact weapons such as batons. Alternatives to bodily force and 

impact weapons are found 

in other less-lethal weapons 

such as pepper spray and 

CEDs. 

Previous studies on 

pepper spray and CEDs 

Pepper spray. Law enforcement agencies rapidly 

adopted pepper spray in the 

late 1980s and early 1990s 

as an alternative to traditional 

chemical agents such as tear 

gas, but its use sparked controversy. Notably, the American Civil Liberties Union of 

Southern California asserted 

that pepper spray was causing in-custody deaths. NIJ 

studies on the link between 

pepper spray and in-custody 

deaths found that the deaths 

were largely a result of positional asphyxia, pre-existing 

health conditions or were 

drug related.9 

Several studies found that 

when agencies adopted the 

use of pepper spray, they 

subsequently had large 

declines in assaults on officers and declines in officer 

and suspect injury rates, 

and associated injuries were 

usually minor.10 Pepper spray 

provides a way to reduce 

injuries. 

CEDs. Many law enforcement agencies noted that 

injury rates for officers and 

suspects declined after they 

introduced CEDs.11 

Medical research, including 

controlled animal trials and 

controlled human trials, has 

produced various insights. 

Some animal studies were 

conducted to learn if CED 
4 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

use could result in ventricular 

fibrillation. Several studies 

showed that standard shocks 

that lasted five to 15 seconds 

did not induce ventricular fibrillation of the heart. Higher 

discharges, 15 to 20 times 

the standard, or those of 

longer duration — two 40-

second exposures — induced 

fibrillation or increased heart 

rhythm in some pigs. In addition, longer exposures led to 

ventricular fibrillation-induced 

death in three pigs.12 

Controlled studies involving healthy human subjects 

(often law enforcement 

trainees) found that subjects experienced significant 

increases in heart rates following exposure, but none 

experienced ventricular 

fibrillation.13 

NiJ study and 

recommendations 

NIJ gathered an expert panel 

of medical professionals 

to study in-custody deaths 

related to CEDs. In its report, 

the panel said that while CED 

use is not risk free, there is 

no clear medical evidence 

that shows a high risk of 

serious injury or death from 

the direct effects of CEDs. 

Field experience with CED 

use shows that exposure 

is usually safe. Therefore, 

law enforcement agencies 

need not avoid using CEDs 

provided they are used in 

line with accepted national 

guidelines.14 

A preliminary review of 

deaths following CED exposure found that many are associated with continuous or 

repeated shocks. There may 

be circumstances in which 

repeated or continuous 

exposure is required, but law 

enforcement officers should 

be aware that the associated 

risks are unknown. Therefore, caution is urged in using 

multiple activations.15 

The seeming safety margins of CED use on normal 

healthy adults may not be 

applicable to small children, 

those with diseased hearts, 

the elderly, those who are 

pregnant and other at-risk 

people. The use of CEDs 

against these populations 

(when recognized) should be 

avoided, but may be necessary if conditions exclude 

other reasonable choices.16 

A suspect’s underlying 

medical conditions may be 

responsible for behavior that 

leads law enforcement officers to subdue him or her. 

Sometimes this includes CED 

use. Abnormal mental status 

in a combative or resistive 

subject, sometimes called 
5 

P o l I C E U S E o F F o R C E 

 

 

 

 

“excited delirium,” may be associated with a risk for sudden 

death. This should be treated 

as a medical emergency.17 

the national survey 

The Police Executive Research Forum conducted a 

survey of state, county and 

municipal law enforcement 

agencies to learn more about 

less-lethal technologies and 

related policies and training. More than 500 agencies 

participated. 

Most agencies have a “useof-force continuum” that is 

covered in training, where 

officers learn to use suitable 

force levels depending on 

circumstances. For example, 

an officer might start by using verbal commands when 

dealing with a suspect. Then 

an officer might move to soft 

empty-hand tactics (such as 

pushing) when faced with 

lack of cooperation or mild 

resistance. The continuum 

covers various circumstances 

up to the use of firearms. 

The survey included various levels of resistance and 

asked agencies to describe 

what force they allow in 

each. Most agencies allow 

only soft tactics against a 

subject who refuses, without 

physical force, to comply 

with commands. Just under 

half allow officers to use 

chemical weapons at that 

point. However, if the subject 

tensed and pulled when an 

officer tried to handcuff him 

or her, most agencies would 

allow chemical agents and 

hard empty-hand tactics, 

such as punching. Many also 

allow for CED use at this 

point but about 40 percent 

do not. Almost three-fourths 

allow CED use if the suspect 

flees, and almost all allow it 

when the subject assumes a 

boxer’s stance. Most agencies do not allow baton use 

until the subject threatens 

the officer by assuming the 

boxer’s stance. 

Three-fourths of the surveyed agencies that use 

CEDs issued them between 

2004 and 2006. Most are 

using Tasers. In most agencies, officers receive four or 

six hours of training, and 63.7 

percent of agencies require 

that officers experience 

activation (i.e., get shocked) 

during training. 

Most agencies do not allow 

CED use against a subject 

who nonviolently refuses 

to comply with commands. 

However, six in 10 allow for 

CED use against a subject 

who tenses and pulls when 

the officer tries to handcuff 

him or her. Agencies usually 

The seeming 

safety margins 

of CED use on 

normal healthy 

adults may not 

be applicable to 

small children, 

those with 

diseased hearts, 

the elderly, 

those who are 

pregnant and 

other at-risk 

people. The 

use of CEDs 

against these 

populations 

(when 

recognized) 

should be 

avoided but may 

be necessary 

if conditions 

exclude other 

reasonable 

choices. 
6 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

 

place the CED with chemical 

agents in their force continuum, meaning that their use 

is typically approved in the 

same circumstances in which 

pepper spray use is allowed. 

CEDs are usually lower on 

the continuum than impact 

weapons. 

One facet of the controversy surrounding CED use 

concerns vulnerable populations and circumstances that 

pose potentially heightened 

risk to the subject. For only 

one circumstance — when 

a subject is near flammable 

substances — do most agencies (69.6 percent) ban CED 

use. 

Some 31 percent forbid CED 

use against clearly pregnant 

women, 25.9 percent against 

drivers of moving vehicles, 

23.3 percent against handcuffed suspects, 23.2 percent 

against people in elevated 

areas and 10 percent against 

the elderly. However, many 

agencies, while not forbidding use in these circumstances, do restrict CED use 

except in necessary, special 

circumstances. 

Analysis of information 

from specific law 

enforcement agencies 

Looking at the experiences 

of specific agencies can yield 

important information that 

might otherwise be lost in 

larger analyses. The researchers used various statistical 

techniques to identify factors 

that increase or decrease the 

odds of injury to officers and 

suspects alike. 

Richland County Sheriff’s 

Department. The Richland 

County Sheriff’s Department 

(RCSD) includes about 475 

sworn officers who serve the 

unincorporated portions of 

Richland County, S.C. Deputies carry Glock .40 caliber 

pistols, collapsible metal 

batons and pepper spray. 

Increasingly, they also carry 

the model X-26 Taser. The 

agency started phasing in 

Taser use in late 2004. During data collection, about 60 

percent of deputies carried 

Tasers. 

Researchers coded 467 useof-force reports covering the 

period from January 2005 to 

July 2006. Of the 49 separate 

injuries recorded for officers 

(three officers had more 

than one injury), 46 involved 

bruises, abrasions or cuts. 

The department recorded 92 
7 

P o l I C E U S E o F F o R C E 

suspect injuries; 69 of those 

were bruises, abrasions or 

cuts. Most of the remaining 

suspect injuries were dog 

bites, but three involved 

broken bones or internal 

injuries. 

Further analysis of the data 

included identifying how 

various factors increased or 

decreased the risk of injury 

to officers or suspects. The 

use of soft empty-hand 

techniques by an officer, active aggression by a suspect 

and suspect use of deadly 

force all increased the risk for 

deputies. 

Soft empty-hand control was 

the most frequent force level 

used by deputies, occurring 

in 59 percent of all use-offorce incidents. These techniques increased the odds of 

officer injury by 160 percent. 

Thus, deputies were at greatest risk for injury when using 

the least force possible. 

Two variables significantly 

decreased the risk for 

suspects. Pepper spray 

use decreased the odds of 

suspect injury by almost 70 

percent, and a deputy aiming 

a gun at a suspect reduced 

injury odds by more than 80 

percent (because the act of 

pointing a gun alone often 

effectively ends the suspect’s resistance). 

However, the use of a canine 

posed, by far, the greatest injury risk to suspects, 

increasing injury odds by almost 40 fold. Suspects who 

displayed active aggression 

toward deputies were also 

more likely to suffer injuries. 

CED use had no effect on 

the likelihood of injury; this is 

inconsistent with the experiences of other agencies, 

suggesting that not every 

agency’s experience with the 

Taser will be the same. 

Miami-Dade Police 

Department. The department has about 3,000 

officers, is the largest law 

enforcement agency in the 

Southeast and is one of the 

largest departments that has 

never issued pepper spray to 

its officers.18 

The researchers examined 

762 use-of-force incidents 

involving a lone officer and a 

lone suspect that occurred 

between January 2002 and 

May 2006. About 70 percent 

of the officers carried Tasers 

by May 2006. Officers were 

substantially less likely to be 

injured than suspects, with 

16.6 percent (124) of officers 

injured and 56.3 percent 

(414) of suspects injured. 

Most injuries were minor, but 

73 suspects (17 percent) 
8 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

suffered serious injuries. Minor injuries included bruises, 

sprains and lacerations. 

Major injuries included bites, 

punctures, broken bones, 

internal injuries and gunshot 

wounds. 

The department does not 

issue pepper spray to its 

line officers, and there were 

few incidents involving guns 

or batons. Analysis of the 

incidents found that the use 

of both soft-hand tactics and 

hard-hand tactics by officers 

more than doubled the odds 

of officer injury. Conversely, 

CED use was associated with 

a 68-percent reduction in the 

odds of officer injury. 

As for suspects, hands-on 

tactics increased the odds 

of injury, the use of canines 

greatly increased the odds 

and CED use substantially 

decreased the odds. 

Seattle Police Department. 

The Seattle Police Department has about 1,200 sworn 

officers. The agency started 

using Tasers in December 

2000. Other less-lethal 

weapons include pepper 

spray, batons and shotgun 

beanbag rounds. The department recorded 676 use-offorce incidents between 

Dec. 1, 2005, and Oct. 7, 

2006. Suspects suffered 

injuries in 64 percent of the 

incidents, while officers suffered injuries in 20 percent 

of the incidents. Officers 

used hands-on tactics in 76 

percent of the incidents. The 

next most frequent type of 

force officers used was the 

Taser (36 percent), followed 

by pepper spray (8 percent). 

Suspects were impaired 

by alcohol, drugs or mental 

illness in 76 percent of the 

incidents. Just over half (52 

percent) of the suspects 

were nonwhite, and 95 percent were male. Analysis of 

the data revealed that Taser 

use was associated with a 

48-percent decrease in the 

odds of suspect injury but did 

not affect officer injury. 

The use of unarmed tactics 

by officers increased the 

odds of officer injury 258 

percent. The odds of officer 

injury increased significantly 

when suspects resisted using physical force or the use 

or threat of use of a weapon. 

Although results were not 

uniform across the agencies, the analysis shows that 

the use of pepper spray and 

CEDs can have a significant 

and positive injury-reduction 

effect. 

Interestingly, nonwhite suspects were less likely to be 

injured than whites in both 
9 

P o l I C E U S E o F F o R C E 

 

 

agencies (Miami and Seattle) 

where suspects’ race was 

available as a variable for 

analysis. Another important 

finding concerns the use of 

canines. While canines were 

used rarely, their use substantially increased the risk of 

injury to suspects in two of 

the agencies. 

Combined agency analysis 

and its limitations 

The researchers also conducted a combined analysis 

of use-of-force data from 12 

large local law enforcement 

agencies.19 The full report 

gives a detailed description 

of the information available 

and the limits of the data. 

Most agencies, for example, 

had details about demographic characteristics of suspects, 

but only four had officer 

demographic information. 

Moreover, the Miami-Dade 

Police Department did not 

use pepper spray while San 

Antonio did not use CEDs. 

Despite the limitations, the 

study’s use of a large sample, representing more than 

25,000 use-of-force incidents, 

allowed the researchers to 

use statistical techniques 

in an effort to learn which 

variables are likely to affect 

injury rates to officers and 

suspects. The use of physical force (hands, feet, fists) 

by officers increased the 

odds of injury to officers and 

suspects alike. However, 

pepper spray and CED use 

decreased the likelihood of 

suspect injury by 65 and 70 

percent respectively. Officer 

injuries were unaffected by 

CED use, while the odds of 

officer injury increased about 

21 percent with pepper spray 

use. 

The researchers noted the 

12-agency analysis yielded 

puzzling results about the 

relationship between pepper spray use and officer 

injury rates. Those results 

are inconsistent with the 

single agency analysis. More 

research may explain the 

differences. 

Longitudinal analysis 

The researchers reviewed 

use-of-force information from 

police departments in Austin, 

Texas, and Orlando, Fla., to 

learn how introducing CEDs 

affected injury rates. This 

quasi-experimental approach 

tracked injuries before and 

after CED introduction. 

The Orlando data include 

4,222 incidents covering 

1998 to 2006. CED use 

began in February 2003. The 

Austin data includes 6,596 

incidents from 2002 to 2006. 

However, CED use was 
10 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

phased in beginning in 2003 

and was not completed until 

June 2004. A large drop in 

injury rates for suspects and 

officers alike occurred in 

both cities following CED 

introduction. 

In both cities, Taser adoption was associated with a 

statistically significant drop 

in average monthly injuries 

to suspects. In Orlando, the 

suspect injury rate dropped 

by more than 50 percent 

compared to the pre-Taser 

injury rate. In Austin, suspect 

injury rates were 30 percent 

lower after full-scale Taser 

deployment. 

In Orlando, the decline in 

officer injury rates were even 

greater than for suspects; 

the average monthly rate 

dropped by 60 percent after 

Taser adoption. In Austin, 

officer injuries dropped by 

25 percent. 

Interviews with officers 

and suspects 

Researchers conducted interviews with 219 officers from 

South Carolina’s Richland 

County Sheriff’s Department, 

35 from the Columbia Police 

Department (CPD), and 35 

suspects involved in use-offorce situations to supplement and add a qualitative 

context to their quantitative 

analyses. Generally, they 

tried to contact officers and 

suspects within 48 hours 

of receiving a use-of-force 

report. Interviews were 

voluntary, and some officers 

and suspects declined to 

participate. 

In nine out of 105 use-offorce incidents, Richland 

County Sheriff’s Department 

officers reported that a Taser 

did not work properly or did 

not have the desired effect. 

In addition, researchers 

received reports of multiple 

Taser hits on a suspect and 

multiple uses of the Taser 

in “drive stun” mode (when 

the Taser is pressed against 

a suspect rather than firing 

darts) to control suspects 

(or, based on the suspects’ 

reports, as punishment). 

These reports indicate that 

some officers are using Tasers multiple times during an 

encounter. 

Nine percent of the officers 

reported injuries, almost all of 

which were scrapes, cuts or 

bruises suffered while struggling with resistant suspects. 

Officers also reported that 26 

suspects (12 percent) were 

injured. Most suspect injuries 

were cuts or abrasions, but 

there were also two dog 

bites, and one suspect was 

shot in the arm after firing at 

officers. 
11 

P o l I C E U S E o F F o R C E 

In 22 cases, researchers 

interviewed both the officers 

and suspects involved in an 

incident. Most suspects said 

officers used excessive or 

unnecessary force to subdue them. Some suspects 

said officers used Tasers 

quickly, and several said the 

officers enjoyed watching 

them endure the pain. Some 

suspects said officers kneed 

them in the back and kicked 

or punched them after they 

were in handcuffs. Some 

also said officers used Tasers on them after they were 

handcuffed. 

Suspects often tell a different 

story than the officers who 

arrest them. In almost all 

cases, suspects said officers 

used excessive force and 

that they were not resisting 

arrest. The officers, for their 

part, said they used minimal 

force to control suspects, 

and did not mention using 

force after a suspect was under control. Officers reported 

that the force used was 

necessary and reasonable. In 

a typical account, a suspect 

said he was unaware there 

was a warrant out for his arrest, and when police confronted him, he did not resist. 

He said the officers “pushed 

me to the ground and put the 

cuffs on ... they didn’t have 

to do that to me.” He said 

that all the officers had to do 

was tell him to “quit acting 

up.” He complained that 

officers should just have told 

him to calm down instead of 

pushing him to the ground. 

By contrast, they said the 

suspect ran away when confronted, so they tackled him. 

These kinds of contradictions 

were common; suspects said 

they did not resist, and officers provided justification for 

the force levels they used. 

In other cases, suspects 

and officers offered radically 

different versions of events. 

For example, in one case, an 

officer said he saw several 

traffic violations and the suspects sped off and stopped, 

with one suspect running 

away. The officers said the 

driver then tried to exit the 

vehicle from the passenger’s 

side holding a shotgun. One 

officer pointed his weapon 

at the suspect, who then 

dropped the shotgun. The 

suspect failed to mention 

the shotgun to researchers 

and only complained that 

officers put the handcuffs 

on too tightly and slammed 

him around in the back of the 

transport vehicle. 

Unlike the Richland County 

Sheriff’s Department, the 
12 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

Columbia Police Department did not use Tasers. 

The officers described 35 

use-of-force incidents. Three 

officers reported that pepper 

spray was ineffective. In all 

three cases, the suspects 

were either drunk or high on 

drugs. One case, in particular, highlighted the potential 

advantages of the Taser over 

pepper spray in some circumstances. In that case, a 6’7”, 

370-pound man wanted for 

domestic violence charged 

an officer with a metal object 

in his hand. The officer used 

pepper spray, but it had no 

effect. The suspect then 

retreated to the apartment 

kitchen and grabbed a knife. 

The officers pointed their 

guns at him and ordered 

him to drop the knife, but he 

refused. He cut and stabbed 

himself with the knife while 

the officers waited for another agency to arrive that 

was equipped with a Taser. 

The suspect cut himself 

more than 100 times before the South Carolina Law 

Enforcement Division arrived 

and used a Taser on him. The 

Taser had an instant effect, 

and officers were then able 

to handcuff the suspect. 

Most injuries in both agencies occurred when officers 

and suspects struggled on 

the ground. The differences 

between the agencies were 

striking. RCSD equips most 

of its deputies with Tasers. 

The deputies collectively 

reported fewer injuries to 

themselves and suspects 

from ground fighting than 

did CPD officers. CPD did 

not issue Tasers, and 31 

percent of its officers reported getting cuts, scrapes and 

bruises from wrestling with 

suspects on the ground. The 

prevalence of ground fighting 

injuries among RCSD officers 

(less than nine percent) was 

lower, as were injuries to 

suspects caused by contact 

with the ground. Some of 

the injuries could have been 

prevented had officers used 

Tasers instead of hands-on 

tactics. 

Implications for policy, 

training and future 

research 

Because of the controversial 

nature and widespread use 

of CEDs, the researchers 

explored their use in detail 

and made recommendations, based on the findings, 

for whether and how CEDs 

should fit into the range of 

less-lethal force alternatives 

available to law enforcement 

officers. 
13 

P o l I C E U S E o F F o R C E 

Factors affecting 

injuries 

Physical force 

The findings clearly show 

the use of physical force and 

hands-on control increase the 

risk of injury to officers and 

suspects. In Richland County, 

S.C., soft empty-hand control 

significantly increased the 

odds of injury to officers, 

while hard empty-hand 

tactics increased the risk of 

injury to suspects. In MiamiDade, both types of force 

increased the risk of injury to 

both officers and suspects. 

In Seattle, use of force increased injury risk to officers 

but not to suspects, while 

the overall analysis (of 12 

agencies) showed increased 

injury risk to suspects and 

especially to officers associated with physical force. This 

increased risk was large. 

When controlling for the use 

of CEDs and pepper spray 

in the overall analysis, using 

force increased the injury 

odds to officers by more than 

300 percent and to suspects 

by more than 50 percent. 

Suspect resistance 

Increasing levels of suspect 

resistance were associated 

with an increased risk of 

injury to officers and suspects. The increased injury 

risk was especially acute for 

officers. In Richland County, 

active aggression and threats 

of deadly force increased 

the odds of officer injury 

by more than 100 percent. 

The odds of suspect injury 

were unchanged in Seattle 

with increased resistance 

levels. These findings suggest that officers, rather than 

suspects, face the most 

increased injury risk when 

suspects resist more 

vigorously. 

Pepper spray 

The findings suggest that, 

at least for suspects, pepper 

spray use reduces the likelihood of injury. In Richland 

County, pepper spray use 

reduced the odds of suspect 

injury by 70 percent but did 

not affect officer injuries. In 

Seattle, pepper spray use 

had no effect on injury rates 

for officers or suspects. 

However, the overall analysis 

(of 12 agencies) showed that 

pepper spray use reduced 

the likelihood of injury to 

suspects by 70 percent, 

which was even more than 

the decline noted with CEDs 

(see below). For officers, 

pepper spray use increased 

the likelihood of injury by 21 

to 39 percent. This finding 
14 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

was unexpected, and more 

research may help to explain 

how officers choose to use 

pepper spray versus CEDs. 

CEDs 

Except for in Richland 

County where its effects 

were insignificant, CED use 

substantially decreased the 

likelihood of suspect injury. 

In Miami-Dade, the odds of 

a suspect being injured were 

almost 90 percent lower 

when a CED was used than 

when it was not. Similarly, 

the odds of suspect injury 

went down by almost 50 

percent when CEDs were 

used in Seattle. The larger 

analysis of 12 agencies and 

more than 24,000 use-offorce cases showed the odds 

of suspect injury decreased 

by almost 60 percent when 

a CED was used. In Richland 

County, Seattle, and in the 

larger analysis, Taser use had 

no effect on officer injuries, 

while in Miami-Dade, officer 

injuries were less likely when 

a Taser was used. Controlling 

for other types of force and 

resistance, CED use significantly reduced the likelihood 

of injuries. CED adoption by 

the Orlando and Austin police 

departments reduced injuries 

to suspects and officers over 

time. 

Demographic 

characteristics 

Apart from officer force and 

suspect resistance, few 

other factors influenced 

injury outcomes. In MiamiDade, male suspects were 

twice as likely to be injured 

as females. The same held 

true for the 12-agency analysis. In that larger analysis, the 

presence of a male suspect 

slightly increased injury risk 

to officers. In Seattle, female 

officers were more than 

twice as likely to be injured 

as male officers. 

placement of pepper 

spray and CeDs on a 

linear use-of-force 

continuum 

People rarely die after being 

pepper sprayed or shocked 

with a Taser. However, if 

injury reduction is the primary 

goal, agencies that allow use 

of these less-lethal weapons 

are clearly at an advantage. 

Both weapons prevent or 

minimize the physical struggles that are likely to injure 

officers and suspects alike. 

Although both cause pain, 

they reduce injuries, and 

according to current medical 

research, death or serious 

harm associated with their 
15 

P o l I C E U S E o F F o R C E 

 

 

 

 

 

 

 

 

 

 

 

 

use is rare. In that sense, 

both are safe and similarly 

effective at reducing injuries. Both should be allowed 

as possible responses to 

defensive or higher levels 

of suspect resistance. This 

recommendation is supported by the findings and 

is now followed by most 

agencies that responded to 

the national survey. 

policy and training 

issues related to CeDs 

CEDs were used far more 

often (four to five times 

more often) than pepper 

spray among agencies that 

equipped officers with CEDs 

and were sometimes used at 

rates that exceeded emptyhand control. Unlike pepper 

spray, CEDs do not require 

decontamination and do not 

carry the risk of accidental 

“blow back” that often occurs with pepper spray use. 

However, they do entail the 

removal of prongs and the 

potential for an unintended 

shock to an officer. Even 

with these concerns, they 

are rapidly overtaking other 

force alternatives. Although 

the injury findings suggest 

that substituting CEDs for 

physical control tactics may 

be useful, their ease of use 

and popularity among officers 

raise the specter of overuse. 

The possible overuse of 

CEDs has several dimensions. CEDs can be used 

inappropriately at low levels 

of suspect resistance. Law 

enforcement executives can 

manage this problem with 

policies, training, monitoring 

and accountability systems 

that provide clear guidance 

(and consequences) to officers regarding when and 

under what circumstances 

CEDs should be used, or 

when they should not be 

used. 

Besides setting the resistance threshold appropriately, 

good policies and training 

would require that officers 

evaluate the age, size, 

gender, apparent physical capabilities and health concerns 

of a suspect. In addition, 

policies and training should 

prohibit CED use in the presence of flammable liquids or 

in circumstances where falling would pose unreasonable 

risks to the suspect (in elevated areas, adjacent to traffic, etc.). Policies and training 

should address the use of 

CEDs on suspects who are 

controlled (e.g., handcuffed 

or otherwise restrained) and 

should either prohibit such 

use outright or limit them to 

clearly defined, aggravated 

circumstances. 
16 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In addition to being used too 

often, CEDs can be used too 

much. Deaths associated 

with CED use often involve 

multiple Taser activations 

(more than one Taser at a 

time) or multiple five-second 

cycles from a single Taser. 

CED policies should require 

officers to assess continued 

resistance after each standard cycle and should limit 

use to no more than three 

standard cycles. Following CED deployment, the 

suspect should be carefully 

observed for signs of distress 

and should be medically 

evaluated at the earliest 

opportunity. 

Directions for future 

research 

CEDs can be used too much 

and too often. A critical research question focuses 

on the possibility of officers 

becoming too reliant on CEDs. 

During interviews with officers 

and trainers, the researchers 

heard comments that hinted 

at a “lazy cop” syndrome. 

Some officers may turn to a 

CED too early in an encounter 

and may relying on a CED 

rather than rely on the officer’s conflict resolution skills 

or even necessary hands-on 

applications. Research should 

explore how officers who 

have CEDs perceive threats, 

compared to officers who do 

not have them. In addition, 

it is important to determine 

when, during an encounter, 

an officer deploys the CED. 

Another important CEDrelated research project 

would be a case study of 

in-custody deaths involving CED use and a matched 

sample of in-custody deaths 

when no CED use occurred. 

Advocacy groups argue that 

CEDs can cause or contribute to suspect deaths. The 

subjects in CED experimental settings have all been 

healthy people in relatively 

good physical condition who 

are not under the influence 

of alcohol or drugs. There 

is no ethical way to expose 

overweight suspects who 

have been fighting or using 

drugs to the effects of CEDs, 

so an examination of cases 

where similar subjects lived 

and died may shed some 

light on the reasons for the 

deaths. Law enforcement 

officials typically argue that 

most if not all the subjects 

who died when shocked by 

a CED would have died if 

the officers had controlled 

and arrested them in a more 

traditional hands-on fight. 

At this point, the argument 

is rhetorical and research is 

needed to understand the 

differences and similarities in 

cases where suspects died 
17 

P o l I C E U S E o F F o R C E 

in police custody, including 

deaths where a CED may or 

may not have been involved. 

Finally, female officers in 

Seattle were more than twice 

as likely to suffer injuries as 

males. Perhaps the finding 

in Seattle is an anomaly, but 

it should be investigated 

further. 

Notes 

1. Police Executive Research Forum, 

“Comparing Safety Outcomes 

in Police Use-of-Force Cases for 

Law Enforcement Agencies That 

Have Deployed Conducted Energy 

Devices and a Matched Comparison 

Group That Have Not: A QuasiExperimental Evaluation,” report 

submitted to the National Institute 

of Justice, grant number 2006-IJCX-0028, 2009: 13. 

2. http://www.ojp.usdoj.gov/nij/ 

topics/technology/less-lethal/ 

how-ceds-work.htm. 

3. Ibid. 

4. http://www.ojp.usdoj.gov/nij/ 

topics/technology/less-lethal/ 

monitoring-ced-use.htm. 

5. Edwards, S.M., J. Granfield, and J. 

Onnen, Evaluation of Pepper Spray, 

Research in Brief, Washington, D.C.: 

U.S. Department of Justice, National 

Institute of Justice, February 1997, 

NCJ 162358; Granfield, J., J. Onnen, 

and C.S. Petty, Pepper Spray and 

In-Custody Deaths, Alexandria, Va.: 

International Association of Chiefs of 

Police, 1994; Petty, C.S., “Deaths in 

Police Confrontations When Oleoresin Capsicum Is Used,” final report, 

Washington, D.C.: U.S. Department 

of Justice, National Institute of Justice, 2004, NCJ 204029. 

6. Henriquez, M., “IACP National 

Database Project on Police Use of 

Force,” in Use of Force by Police: 

Overview of National and Local Data, 

Washington, D.C.: U.S. Department 

of Justice, National Institute of 

Justice and Bureau of Justice Statistics, 1999: 19-24; Kaminski, R., C. 

DiGiovanni, and R. Downs, “The Use 

of Force Between the Police and 

Persons With Impaired Judgment,” 

Police Quarterly, 7 (2004): 311-338; 

Smith, M.R., and M. Petrocelli, 

“The Effectiveness of Force Used 

by Police in Making Arrests,” Police 

Practice and Research, 3 (2002): 

201-215. 

7. Alpert, G.P., and R.G. Dunham, 

“Analysis of Police Use-of-Force 

Data,” final report, Washington, 

D.C.: U.S. Department of Justice, 

National Institute of Justice, 2000, 

NCJ 183648; Alpert, G.P., and R.G. 

Dunham, Understanding Police Use 

of Force: Officers, Suspects, and 

Reciprocity, Cambridge, NY: Cambridge University Press, 2004; Kaminski, R.J., and D.W.M. Sorensen, 

“A Multivariate Analysis of Individual, Situational, and Environmental Factors Associated with Police 

Assault Injuries,” American Journal 

of Police, 14 (3/4) (1995): 3-48. 

8. See, e.g., Alpert and Dunham, 

2000, note 7. 

9. Granfield, Onnen, and Petty, 1994, 

note 5; Petty, 2004, note 5. 

10. Edwards, Granfield, and Onnen, 

1997, note 5; Kaminski, R.J., S.M. 

Edwards, and J.W. Johnson, “Assessing the Incapacitative Effects 

of Pepper Spray During Resistive 

Encounters With the Police,” 
18 

R E S E A R C H I N B R I E F / M A y 2 0 1 1 

Policing: An International Journal of 

Police Strategies and Management, 

22 (1999): 7-29; Lumb, R.C., and 

P.C. Friday, “Impact of Pepper Spray 

Availability on Police Officer Useof-Force Decisions,” Policing: An 

International Journal of Police Strategies and Management, 20 (1997): 

136-148; National Institute of Justice, The Effectiveness and Safety of 

Pepper Spray, Research for Practice, 

Washington, D.C.: U.S. Department 

of Justice, National Institute of Justice, 2003, NCJ 195739; Nowicki, E., 

“Oleoresin Capsicum: A Non-Lethal 

Force Alternative,” Law Enforcement Technology, 20 (1993): 24-27; 

Smith and Petrocelli, 2002, note 6. 

11. Charlotte-Mecklenburg Police 

Department, Taser Project: First 

Year—Full Deployment Study. Charlotte, N.C.: Charlotte-Mecklenburg 

Police Department, 2006; Hougland, 

S., C. Mesloh, and M. Henych, “Use 

of Force, Civil Litigation, and the 

Taser,” FBI Law Enforcement Bulletin, 74 (2005): 24-30; Jenkinson, E., 

C. Neeson, and A. Bleetman, “The 

Relative Risk of Police Use-of-Force 

Options: Evaluating the Potential for 

Deployment of Electronic Weaponry,” Journal of Clinical Forensic 

Medicine, 13 (2005): 229-241. 

12. Dennis, A.J., D.J. Valentino, R.J. 

Walter, K.K. Nagy, J. Winners, F. 

Bokhari, D.E. Wiley, K.T. Joseph, 

and R.R. Roberts, “Acute Effects of 

TASER X26 Discharges in a Swine 

Model,” The Journal of Trauma, 

Injury, Infection and Critical Care, 

63 (2007): 581-590; Esquivel, A., 

E. Dawe, J. Sala-Mercado, R. Hammond, and C. Bir, “The Physiological 

Effects of a Conducted Electrical Weapon in Swine,” Annals of 

Emergency Medicine, 50 (2007): 

576-583; Ho, J.D., J.R. Miner, D.R. 

Lakireddy, L.L. Bultman, and W.G. 

Heegaard, “Cardiovascular and 

Physiologic Effects of Conducted 

Electrical Weapon Discharge in Resting Adults,” Academic Emergency 

Medicine, 13 (2006): 589-595; Lakkireddy, D., D. Wallick, A. Verma, 

K. Ryschon, W. Kowalewski, O. 

Wazni, J. Butany, D. Martin, and P.J. 

Tchou, “Cardiac Effects of Electrical 

Stun Guns: Does Position of Barbs 

Contact Make a Difference?” Pacing 

and Clinical Electrophysiology, 31 

(2008): 398-408; McDaniel, W.C., 

R.A. Stratbucker, M. Nerheim, and 

J.E. Brewer, “Cardiac Safety of Neuromuscular Incapacitating Defensive 

Devices,” Pacing and Clinical Electrophysiology, 28 (2005): s284-s287; 

Nanthakumar, K., I.M. Billingsley, S. 

Masse, P. Dorian, D. Cameron, V.S. 

Chauhan, E. Downar, and E. Sevaptsidis, “Cardiac Electrophysiological 

Consequences of Neuromuscular 

Incapacitating Device Discharges,” 

Journal of the American College of 

Cardiology, 48 (2006): 798-804; Roy, 

O.Z., and A.S. Podgorski, “Tests 

on a Shocking Device — The Stun 

Gun,” Medical and Biological Engineering and Computing, 27 (1989): 

445-448; Stratbucker, R., R. Roeder, 

and M. Nerheim, “Cardiac Safety of 

High Voltage Taser X26 Waveform,” 

Engineering in Medicine and Biology 

Society, Proceedings of the 25th 

Annual International Conference of 

the IEEE EMBS, Cancun, Mexico, 

1094-678X, 4 (2003): 3261-3262; 

Walter, R., A. Dennis, D. Valentina, 

B. Margeta, K. Nagy, F. Bokhari, D. 

Wiley, K. Joseph, and R. Roberts, 

“TASER X26 Discharges in Swine 

Produce Potentially Fatal Ventricular 

Arrhythmias,” Academic Emergency 

Medicine, 15 (2008): 66-73. 

13. Dawes, D.M., J.D. Ho, M.A. 

Johnson, E. Lundin, T.A. Janchar, 

and J.R. Miner, “15-Second Conducted Electrical Weapon Exposure 
19 

P o l I C E U S E o F F o R C E 

 

 

Does Not Cause Core Body Temperature Elevation in Non-Environmentally 

Stressed Resting Adults,” Forensic 

Science International, 176 (2008): 

253-257; Dawes, D.M., J.D. Ho, and 

J.R. Miner, “The Effect of a CrossChest Electronic Control Device 

Exposure on Breathing,” Annals of 

Emergency Medicine, 54 (2008): 

65; Dawes, D.M., J.D. Ho, M.A. 

Johnson, E. Lundin, and J.R. Miner, 

“15-second Conducted Electrical Weapon Application Does Not 

Impair Basic Respiratory Parameters, 

Venous Blood Gases, or Blood 

Chemistries and Does Not Increase 

Core Body Temperature,” Annals 

of Emergency Medicine, 50 (2007): 

6; Dawes, D.M., J.D. Ho, M.A. 

Johnson, E. Lundin, and J.R. Miner, 

“Breathing Parameters, Venous 

Blood Gases, and Serum Chemistries With Exposure to a New Wireless Projectile Conducted Electrical 

Weapon in Human Volunteers,” 

Annals of Emergency Medicine, 50 

(2007): 133; Ho, J.D., D.M. Dawes, 

L.L. Bultman, J.L. Thacker, L.D. 

Skinner, J.M. Bahr, M.A. Johnson, 

and J.R. Miner, “Respiratory Effect 

of Prolonged Electrical Weapon 

Application on Human Volunteers,” 

Academic Emergency Medicine 14 

(3) (2007): 197-201; Ho, J.D., J.R. 

Miner, D.R. Lakireddy, L.L. Bultman, 

and W.G. Heegaard, “Cardiovascular 

and Physiologic Effects of Conducted Electrical Weapon Discharge 

in Resting Adults,” Academic 

Emergency Medicine, 13 (2007): 

589-595; Ho, J.D., D.M. Dawes, 

R.F. Reardon, A.L. Lapine, and J.R. 

Miner, “Echocardiographic Determination of Cardiac Rhythm During 

Trans-Thoracic Wireless Conducted 

Electrical Weapon Exposure,” Annals of Emergency Medicine, 52 

(2008): 62; Levine, S.D., C. Sloane, 

T.C. Chan, J. Dunford, and G. Vilke, 

“Cardiac Monitoring of Human Subjects Exposed to the Taser,” Journal 

of Emergency Medicine, 13 (2007): 

47; Levine, S.D., C. Sloane, T.C. 

Chan, G. Vilke, and J. Dunford, “Cardiac Monitoring of Subjects Exposed 

to the Taser,” Academic Emergency Medicine, 12 (2005): 71; Vilke, 

G.M., C. Sloane, K.D. Bouton, F.W. 

Kolkhorst, S. Levine, T. Neuman, E. 

Castillo, and T.C. Chan, “Physiological Effects of a Conducted Electrical Weapon on Human Subjects,” 

Annals of Emergency Medicine, 26 

(2007): 1-4. 

14. National Institute of Justice, 

Study of Deaths Following Electro 

Muscular Disruption, Special Report, 

Washington, D.C.: U.S. Department 

of Justice, National Institute of Justice, 2011: 3, NCJ 233432. 

15. Ibid., 4. 

16. Ibid. 

17. Ibid., 5. 

18. The MDPD provides police 

services to the unincorporated areas 

of Miami-Dade County, Fla., which 

together contain more than 1 million 

people in a 1,840 square mile area. 

19. The agencies included police 

and sheriff’s departments in Austin, 

Texas; Cincinnati, Ohio; Harris 

County, Texas; Hillsborough County, 

Fla.; Los Angeles (both the city and 

the county); Miami-Dade, Fla.; Nashville, Tenn.; Orlando, Fla.; Richland 

County, S.C.; San Antonio, Texas; 

and Seattle, Wash. 



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