New Study May “Radically Alter” How Police Deadly Force Is Viewed (Part 1)

Print Friendly, PDF & Email

1 of a 2-Part Series

The story is a frequent staple of the evening news. An officer shoots and kills a minority subject who turns out to be…unarmed. Protests explode, and the familiar litany is again asserted: racial bias by the cops underlies many of these inflammatory events.

Now a new study by a member of the Force Science Research Center’s national advisory board confirms what law enforcement officials have argued all along: Such controversial shootings aren’t about race. What really prompts an officer to pull the trigger in circumstances that are rapidly evolving and uncertain is the suspect’s behavior.

“That’s the bottom-line finding,” researcher Tom Aveni told Force Science News. “If you confront a police officer in what appears to be a felonious context, it’s the way you act that will get you shot-not your race. And that’s true regardless of the officer’s sex, age, experience, or type of duty location.”

In fact, Aveni was able to pinpoint specific body-language that tends to be associated with the decision to shoot.

Moreover, among less important factors that also influence decision-making, even a suspect’s clothing and age are likely to be more compelling than his or her ethnicity in determining officers’ reactions.

Aveni’s conclusions come from his detailed analysis of the reactions of 307 officers who engaged armed and unarmed suspects in simulated confrontations designed to accurately reflect conditions under which officer-involved shootings often occur. Founder of the consulting and training organization The Police Policy Studies Council in addition to serving on FSRC’s board, Aveni funded the project largely from his own pocket. He also received some financial aid and substantial logistical assistance from the Michigan Municipal Risk Management Authority, an insurer of law enforcement agencies.

The full report of his findings is titled “A Critical Analysis of Police Shootings Under Ambiguous Circumstances.

“This is a very significant, first-of-its-kind investigation,” says Dr. Bill Lewinski, executive director of FSRC at Minnesota State University-Mankato. “Tom Aveni has measured critical variables in shooting situations that other researchers have ignored completely. As a result, his findings are far more realistic and meaningful in identifying the factors that truly drive deadly force decision-making.”

Aveni himself believes the study potentially will “radically alter the way police use of deadly force is examined in the future.”


Something of a dual motivation propelled him into the study, which was “years in the making,” Aveni says. For one thing, he was intrigued by an assertion made by the ACLU some years ago that 25% of all suspects shot by police are “unarmed and not-assaultive.” And he was also curious about research concerning the “disproportionate” use of deadly force by officers against racial minorities.

“Race has been explored extensively as a factor” in police shootings, Aveni says, particularly in those where no suspect weapon is found after the smoke clears. “The implication has been that the police are racist” and that negative stereotyping causes them to overreact with excessive force in circumstances where, in fact, no lethal threat exists.

As Aveni reviewed existing research, he found that studies on the subject seemed invariably to explore the matter “without meaningful context.” They merely reported gross numbers without “delving deeply into the generally overlooked critical micro-behavioral components that are the very essence of the police decision-making process.”

Consequently, if minorities indeed are disproportionately targeted in “ambiguous” shootings where a deadly threat is not clearly confirmed before an officer fires, “one is left to wonder why.”

With the cooperation of 6 law enforcement agencies in Michigan-3 municipal police departments and 3 sheriff’s departments, representing urban, suburban, and rural jurisdictions-Aveni set about to “better understand the behavior of officers forced to make critical, split-second decisions that may result in the taking of a life.”


A troupe of actors from a local theater, representing a diversity of races, sexes, ages, and attire, were videotaped depicting subjects at a furniture store location. They performed specifically prescribed reactions as if interrupted by an officer responding to a purported robbery-in-progress, a burglar alarm activation, or a possible mugging-in-progress.

Using a mix of players, clothing, and reactions, 80 different scenarios were taped. These were then projected in random order on a laser-based IES Interactive Training MILO system. Participating officers, also diverse as to race, gender, age, experience, agency affiliation, and assignment, then were randomly exposed, one at a time, to 3 different scenarios with 3 different outcomes:

  • a suspect who intends to surrender empty-handed,
  • a suspect who intends to surrender with a non-weapon object (cell phone, flashlight, police ID wallet) in hand,
  • and a subject determined to shoot.

All scenarios were taped in low-light conditions, to “inject more ambiguity into the situations” and to reflect the fact that more than 70% of police shootings of unarmed subjects occur in settings with unfavorable illumination.

“Realistic uncertainties like officers regularly encounter on the street were built into all the scenarios,” Aveni explains. Officers were told that the robbery-in-progress report, for example, had come via a 911 hang-up; no further details available, including no description of the offender and no information on whether a weapon is involved. When the participating officer “arrives” at the scene, viewing things from the camera’s perspective, an unidentified subject bursts out of the front door and starts to run away.

When an officer responds to the burglar alarm, he or she spots a subject trying to crowbar a side door. The subject drops the bar, eliminating the only potential weapon-that’s visible, at least.

In the possible mugging scenario, officers were told only that they are doing business checks in an industrial park at 0100 hours. Yelling that suggests a “verbal altercation” is heard. The camera leads the participating officer around a visual obstruction, where he or she then sees one individual pushing another against a wall; again, no explanation immediately available.

Officers stood about 15 feet away from the action. They were told to react to what they saw on the screen as they would on the street. Most immediately issued loud verbal commands: “Police! Don’t move!” or “Show me your hands!” or both. In each scenario, the subject “responded” by standing with back to the officer, hands out of sight at waist level. “This added to the ‘threat ambiguity’ of each situation,” Aveni says.

Each subject had been coached to look back over his or her shoulder at least once during the encounter, as if taking a “target glance” at the participating officer. Then, unexpectedly, the subject abruptly turned to the left, toward the officer. Hands were kept at waist level at least through the first half-turn, and then they moved up somewhat as the turn was completed.

Subjects who were armed (1/3 of the scenarios) fired a .38 Special S&W M640 revolver, loaded with full-flash Hollywood blanks. The participating LEOs were warned that if someone on screen shot at them first, a modified paintball apparatus beside the simulator screen would also begin firing foam-rubber balls at them. “This factor was injected into the study in the hope that it might diminish participant apathy or complacency,” Aveni explains.

The scenarios lasted, at maximum, about 30 seconds apiece. All the “confrontations” were videotaped to allow minute analysis later.


Aveni found that of the 307 LEOs participating, 38%-nearly 4 in every 10-shot unarmed subjects depicted in the scenarios (in all, 117 such subjects got shot). Some officers shot more than one suspect who turned out not to have a weapon. Carefully tabulating and analyzing details of the officers’ actions to illuminate the percentage, he reached several important conclusions:

What didn’t matter. “No significant correlation existed between the officers’ actions and the suspects’ race,” Aveni says. “Likewise, there was no significant correlation between what the officers did and their own gender, age, experience, or type of jurisdiction in which they worked-urban, suburban, or rural.

“Statistically, there was a significant correlation in black officers shooting unarmed subjects. But with only 9 African-American LEOs participating in the study, that number may be too small to warrant firm conclusions.”

What did matter. The strongest correlation was found between the subjects’ actions and the officers’ decision to shoot. Also significant, though of somewhat lesser influence, was the type of crime believed to be involved in the scenario and 2 attributes of the subject-age and attire.

Aveni explains: “Officers were more likely to shoot in the robbery scenario than in the possible mugging and more likely to shoot in the mugging scenario than in the apparent burglary-in-progress.”

The nature of the crime involved, he says, clearly affected the officers’ “vigilance and situational readiness.” Responding to the reported robbery, they were more likely to have their sidearm drawn quickly and pointed at the suspect when verbal commands were issued, compared to the spontaneously discovered possible mugging and the alarm activation call (a frequent false run in police work) where their readiness was “measurably worse.”

Also, officers were “more likely to shoot when the subject was young and also when the subject was wearing scruffy ‘punk’ clothing rather than ‘business’ attire.”

Predictably, officers overwhelmingly shot at suspects when suspects shot at them. But many also fired “preemptively,” before a weapon could actually be discerned, resulting in rounds being delivered to unarmed subjects. “The major influence here was how the subject behaved,” Aveni says. Particularly involved was what he calls “the acting quotient.”

Acting Quotient

All suspects in the scenarios followed the same choreographed pattern of movement: With their back to the participating officer, they initially kept their hands at waist level, glanced over their shoulder, then turned without warning to face the officer, concealing their hands until well into the turn.

Aveni had not anticipated that the actors would perform with different levels of energy and conviction. Yet some performed more “convincingly” than others, and that proved to be a key component of the research.

“The subjects most likely to get shot,” Aveni says, “displayed a high-level ‘acting quotient.’ They performed with unchoreographed nuances. That is, they made their moves with vigorous intensity and speed, versus tepidly. They kept their hands low, rather than high. They tended to crouch partially or fully as they turned instead of remaining upright, and they fully or partially clenched their hands, rather than keeping them open.”

Such energetic movement in a setting where a serious crime appears to be involved “is much less likely to be viewed as innocuous,” Aveni says. “A suspect’s intensity had much to do with whether an officer felt compelled to pull the trigger before the circumstances became manifest. It became one of the most reliable predictors of whether a person got shot.”

Time Pressure

For their own safety, officers had little time to react. Even with “tepid” movements, the suspects’ hands came around “almost always too fast to determine” the true nature of any object being held or whether the hands were, in fact, empty, Aveni says.

As the hands typically swung through an arc of 4-5 feet, the officers’ eye movement inevitably lagged behind, so that the action was perceived “as a blur or a smear of motion. Judgment about what, if anything, the suspects held could not be made with certainty until the hand movement stopped. When a suspect had a gun, that was too late.”

With an officer behind the reactionary curve, Aveni says, “the lag time can allow the suspect to fire one or more shots before the officer can shoot back.” Indeed, in the study armed suspects were able to shoot first 61% of the time.

From a critical juncture in a scenario, an officer typically had “1/3 of a second or less” to decide whether to use deadly force or risk being shot, Aveni claims.

“Those officers who managed to shoot armed suspects before the suspect was able to fire seemed to have elected to use deadly force before it could be clearly determined that the suspect did, in fact, have a handgun. The officers decided to fire either before the suspect started to turn or at the earliest possible moment turning was perceived.

“This tends to explain why a significant percentage of unarmed subjects, who intended to surrender with or without innocuous objects in hand, also were shot.”

All unarmed role players in the scenarios were told to culminate their movements in the “surrender” position: hands held at sternum height or above, palms facing forward, fingers pointed “mostly upward.”

Aveni reports that “92% of the unarmed subjects who were shot during the study were in the ‘surrender position’ ” at the time the officers’ shots reached them.

Lewinski offers some pertinent observations. First, he says, “time pressure is notorious for significantly increasing errors in judgment. That’s true not just in officer-involved shootings but also in activities that are not life-threatening, such as fingerprint analysis. As time tightens, the incidence of false-positive and false-negative decisions expands.”

Time plays into these situations in another critical way, too, Lewinski explains. “A passage of time necessarily occurs between the instant an officer makes a decision to shoot and the instant his rounds impact. Force Science research has clearly established that if a suspect is moving, his position will be different when a bullet strikes than it was when the decision was made to shoot.

“This can account for subjects being shot in the surrender posture. They weren’t necessarily in those ‘no-shoot’ postures when the officer’s shooting decision was made.”

Aveni’s study further revealed “a common tendency” for officers to continue shooting once they started. Aveni offers 2 explanations:

  1. “it takes time to ‘apply the brakes’ of a neuromuscular response” like firing a gun. Studies by FSRC have shown that officers, on average, fire 2 or more shots after they’ve received a visual cue that shooting should end;
  2. the scenarios Aveni used did not have a branching capability, so the suspects did not fall when “hit.” Thus, “any officer trained to ‘fire until your foe falls’ would likely continue shooting.”

Lewinski elaborates. “In the midst of shooting to save their lives, officers often can’t see where their bullets are striking. They rely on highly detectable visual cues that the subject has ceased being a threat, such as the suspect dramatically thrusting his or her arms overhead or collapsing.”

“Even then, officers often will continue to shoot because of the perception-reaction lag time, resulting in bullets hitting the body as the suspect falls.”

Agency Differences

Marked differences in performance were evident among the 6 departments that participated in Aveni’s study. At the “highest-frequency” end of the scale, nearly half the officers from one agency shot unarmed suspects. The lowest frequency was compiled by an agency whose participating officers shot unarmed suspects 24% of the time. The rest ranged from 39% to 44%.

“The question will undoubtedly arise: ‘What noted differences were there between the agency with the lowest frequency of mistake-of-fact shootings and the agency with the highest frequency?’ ” Aveni observes, noting that both these agencies patrol urban jurisdictions.

“The answer, simply put: ‘It was a difference in training.’ ”

Leave a Reply


  • Privacy Policy

Privacy Policy

Effective date: January 06, 2019

Force Science Institute, Ltd. (“us”, “we”, or “our”) operates the https://www.forcescience.org/ website (hereinafter referred to as the “Service”).

This page informs you of our policies regarding the collection, use, and disclosure of personal data when you use our Service and the choices you have associated with that data. Our Privacy Policy for Force Science Institute, Ltd. is based on the Privacy Policy Template from Privacy Policies.

We use your data to provide and improve the Service. By using the Service, you agree to the collection and use of information in accordance with this policy. Unless otherwise defined in this Privacy Policy, the terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, accessible from https://www.forcescience.org/

Information Collection And Use

We collect several different types of information for various purposes to provide and improve our Service to you.

Types of Data Collected

Personal Data

While using our Service, we may ask you to provide us with certain personally identifiable information that can be used to contact or identify you (“Personal Data”). Personally identifiable information may include, but is not limited to:

  • Email address
  • First name and last name
  • Phone number
  • Address, State, Province, ZIP/Postal code, City
  • Cookies and Usage Data

Usage Data

We may also collect information on how the Service is accessed and used (“Usage Data”). This Usage Data may include information such as your computer’s Internet Protocol address (e.g. IP address), browser type, browser version, the pages of our Service that you visit, the time and date of your visit, the time spent on those pages, unique device identifiers and other diagnostic data.

Tracking & Cookies Data

We use cookies and similar tracking technologies to track the activity on our Service and hold certain information.

Cookies are files with small amount of data which may include an anonymous unique identifier. Cookies are sent to your browser from a website and stored on your device. Tracking technologies also used are beacons, tags, and scripts to collect and track information and to improve and analyze our Service.

You can instruct your browser to refuse all cookies or to indicate when a cookie is being sent. However, if you do not accept cookies, you may not be able to use some portions of our Service. You can learn more how to manage cookies in the Browser Cookies Guide.

Examples of Cookies we use:

  • Session Cookies. We use Session Cookies to operate our Service.
  • Preference Cookies. We use Preference Cookies to remember your preferences and various settings.
  • Security Cookies. We use Security Cookies for security purposes.

Use of Data

Force Science Institute, Ltd. uses the collected data for various purposes:

  • To provide and maintain the Service
  • To notify you about changes to our Service
  • To allow you to participate in interactive features of our Service when you choose to do so
  • To provide customer care and support
  • To provide analysis or valuable information so that we can improve the Service
  • To monitor the usage of the Service
  • To detect, prevent and address technical issues

Transfer Of Data

Your information, including Personal Data, may be transferred to — and maintained on — computers located outside of your state, province, country or other governmental jurisdiction where the data protection laws may differ than those from your jurisdiction.

If you are located outside United States and choose to provide information to us, please note that we transfer the data, including Personal Data, to United States and process it there.

Your consent to this Privacy Policy followed by your submission of such information represents your agreement to that transfer.

Force Science Institute, Ltd. will take all steps reasonably necessary to ensure that your data is treated securely and in accordance with this Privacy Policy and no transfer of your Personal Data will take place to an organization or a country unless there are adequate controls in place including the security of your data and other personal information.

Disclosure Of Data

Legal Requirements

Force Science Institute, Ltd. may disclose your Personal Data in the good faith belief that such action is necessary to:

  • To comply with a legal obligation
  • To protect and defend the rights or property of Force Science Institute, Ltd.
  • To prevent or investigate possible wrongdoing in connection with the Service
  • To protect the personal safety of users of the Service or the public
  • To protect against legal liability

Security Of Data

The security of your data is important to us, but remember that no method of transmission over the Internet, or method of electronic storage is 100% secure. While we strive to use commercially acceptable means to protect your Personal Data, we cannot guarantee its absolute security.

Service Providers

We may employ third party companies and individuals to facilitate our Service (“Service Providers”), to provide the Service on our behalf, to perform Service-related services or to assist us in analyzing how our Service is used.

These third parties have access to your Personal Data only to perform these tasks on our behalf and are obligated not to disclose or use it for any other purpose.


We may use third-party Service Providers to monitor and analyze the use of our Service.

  • Google AnalyticsGoogle Analytics is a web analytics service offered by Google that tracks and reports website traffic. Google uses the data collected to track and monitor the use of our Service. This data is shared with other Google services. Google may use the collected data to contextualize and personalize the ads of its own advertising network.You can opt-out of having made your activity on the Service available to Google Analytics by installing the Google Analytics opt-out browser add-on. The add-on prevents the Google Analytics JavaScript (ga.js, analytics.js, and dc.js) from sharing information with Google Analytics about visits activity.For more information on the privacy practices of Google, please visit the Google Privacy & Terms web page: https://policies.google.com/privacy?hl=en

Links To Other Sites

Our Service may contain links to other sites that are not operated by us. If you click on a third party link, you will be directed to that third party’s site. We strongly advise you to review the Privacy Policy of every site you visit.

We have no control over and assume no responsibility for the content, privacy policies or practices of any third party sites or services.

Children’s Privacy

Our Service does not address anyone under the age of 18 (“Children”).

We do not knowingly collect personally identifiable information from anyone under the age of 18. If you are a parent or guardian and you are aware that your Children has provided us with Personal Data, please contact us. If we become aware that we have collected Personal Data from children without verification of parental consent, we take steps to remove that information from our servers.

Changes To This Privacy Policy

We may update our Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page.

We will let you know via email and/or a prominent notice on our Service, prior to the change becoming effective and update the “effective date” at the top of this Privacy Policy.

You are advised to review this Privacy Policy periodically for any changes. Changes to this Privacy Policy are effective when they are posted on this page.

Contact Us

If you have any questions about this Privacy Policy, please contact us:

  • By email: support@forcescience.org
  • By visiting this page on our website: https://www.forcescience.org/contact
  • By phone number: 866-683-1944
  • By mail: Force Science Institute, Ltd.