Originally published on the Force Science Institute website. Republished here with permission.
“The officer should have waited until he actually saw the suspect’s gun. If the suspect tried to shoot him, he could have shot first.”
The above quote didn’t come from an angry anti-police protester or a biased civil rights attorney. It came from a police legal adviser. It came from an intelligent, civic-minded, pro-police advocate. And he’s not alone in his thinking. Some of our strongest allies have trouble understanding the complexity of use-of-force decisions. Even now many of you are remembering a close friend or family member asking, “Why didn’t they just shoot him in the leg?”
In fairness, understanding and properly judging police use of force is not an easy task.
Judges and juries need experts to help them think like “reasonable officers.” Attorneys spend months researching and arguing the law. Opposing academics debate police practices, behavioral science and video accuracy. Officers may even disagree about threat assessments and force options, and the law allows for that.
But there is one thing reasonable people can no longer dispute: action beats reaction. If an armed suspect decides to shoot first, an officer is not going to have enough time to prevent the initial shots once they start.
It is why we expect officers to maintain unquestioned command at the scene of investigations. Why officers tell people not to move. And why “Stop!” means stop.
Does that mean officers have to shoot first? No, but they better do something: Move. Create distance. Find cover. De-escalate. All great ideas under the right circumstances.
Of course, under the right circumstances, initiative, surprise and speed may be better options.  Sometimes officers can safely disengage, reconsider their approach and avoid the fight. Often, they can’t.
It’s in those moments – when suspects refuse to follow orders, refuse to stop moving, refuse to show their hands – it’s in those moments that officers must know and balance the risk of waiting to see the gun.
THE PROBLEM WITH WAIT AND SEE
When our anonymous legal adviser shared his belief that officers should wait to positively identify a gun, I invited him to confront the reality of his suggestion.
Here was his argument. If an officer has their gun out and pointed at a suspect, who they reasonably believe is armed, they should wait until they positively identify the gun before responding to the threat. If the suspect tries to shoot the officer, the officer has the advantage and can shoot first.
Here’s why he’s wrong.
Speed of assault: Our research tells us a standing suspect can draw a pistol from their waistband, point and shoot in an average of .25 seconds.  Our research also tells us that after the first trigger pull, each subsequent trigger pull will average another .25 seconds.  At those speeds, how many rounds can the suspect fire before the officer perceives the gun, decides to shoot, and pulls the trigger?
Speed of response: We tested how fast officers can shoot when a simple light comes on. That’s about .31 seconds – .25 seconds to recognize the light and another .06 seconds to pull the trigger.  But that was a very simple scenario. See light, pull trigger.
What about a more complex scenario? One light? Don’t shoot. Two lights? Don’t shoot. Three lights? Shoot. We tested that as well and found that the complex scenario doubled the average reaction time.
Officers took an average of .56 seconds to perceive the lights, decide and begin pulling the trigger. Add another .06 seconds to complete the trigger pull and the officer was getting the “first round” off in .62 seconds. 
But officers aren’t trained to “just pull the trigger.” Instead, they are trained to conduct threat assessments while maintaining their gun in various ready positions. These positions allow officers to focus their attention on the suspect (and the environment), while significantly reducing the time it takes to respond with aimed fire.
When we studied the speed in which officers could respond from various ready positions, we found the bootleg position (pistol held behind the leg) was the slowest, taking an average of 1.3 seconds to raise the weapon, acquire a sight picture and fire one round. The high ready position (pistol held extended just below the officer’s line of sight) resulted in the fastest average response time at .83 seconds.
ACCOUNTING FOR THE REAL WORLD
If we presume the officer in our hypothetical scenario adopted the faster high ready position, their aimed response time would likely still be longer than .83 seconds. That’s because, in our experiment, the officer was again reacting to a simple stimulus. The light went on, he raised his weapon, aimed and fired.
In the real world, officers do not have the luxury of standing perfectly still, intently focusing on possible weapons. They are scanning for available cover, improving their position, watching for crossfire, considering backdrops, attempting de-escalation, communicating with responding units and coordinating with backup officers. This divided attention can significantly increase the time it takes for an officer to accurately perceive and consciously verify that a suspect has pulled a gun.
But multitasking isn’t the only factor that affects perception and threat recognition. In the real world, an officer’s physical capacity to see can affect perception, identification and response time; as can environmental conditions like distance, light, shadows, wind, rain and physical obstructions.
We know that divided attention, physical limitations and the environment can slow perception and response time. The question is, by how much? We don’t know.
In complex, real-world use-of-force encounters, response time simply has too many variables to guess. But whatever that response time proves to be, it will be significantly longer than the .83 seconds necessary to respond to a simple light change.
That said, we don’t need the exact numbers to make our point. Let’s imagine our hypothetical officer was only focused on the suspect and had no distractions. If they immediately recognized the gun as it was being aimed in their direction, we could presume an average response time of .83 seconds. But even assigning the officer this artificially fast response time, the suspect is still able to pull the trigger 3 or 4 times before the officer can fire once. That’s assuming the incoming rounds didn’t extend the officer’s response time – or prevent it altogether.
To admit that action beats reaction is not to endorse a so-called “shoot first” mentality. Reaction studies have done much more than help us understand time-compressed shooting decisions.
Police, more than any other profession, appreciate the immense difficulty of identifying and responding to real-world assaults. To avoid split-second decisions, they have learned to recognize and value threat cues and suspicious patterns of conduct (schemas). Knowing the speed of assaults is why they give orders and prioritize tactics that reduce a suspect’s ability, opportunity and willingness to assault them.
When circumstances tend toward a possible armed assault, speed studies remind officers to aggressively look to buy time, create space and negotiate from positions of advantage, before the threat materializes – so that nobody has to shoot first.
1. Dysterheft Robb J, Lewinski W, Pettitt R. et al. The influence of officer positioning on movement during a threatening traffic stop scenario. Law Enforcement Executive Forum. 2013;13:98–109 (Multiple research subjects prevented the “armed attack” by quickly moving toward the suspect and controlling or deflecting the weapon.)
2. Lewinski B. Why is the suspect shot in the back? Finally, hard data on how fast the suspect can be—in 11 different shooting scenarios. The Police Marksman. 2000;25(6):20-28.
3. Lewinski W, Redmann C. New developments in understanding the behavioral science factors in the “stop shooting” response. Law Enforcement Executive Forum. 2009;9(4):38.
4. Dysterheft J, Hudson W and Lewinski, W. Police officer reaction time to start and stop shooting: The influence of decision-making and pattern recognition. Law Enforcement Executive Forum. 2014;14.
5. Bushey J, Dicks N, Dysterheft J et al. Ambushes leading cause of officer fatalities – when every second counts: Analysis of officer movement from trained ready tactical positions.” Law Enforcement Executive Forum. 2015;15.
About the author
Von Kliem is a senior policy attorney for Lexipol, co-owner of Von Kliem Consulting, LLC, and editor-in-chief for Force Science News. With nearly 30 years in the criminal justice field, Von has held positions including patrol officer and supervisor, gang and drug investigator, senior use of force instructor and jailer. His legal positions included chief prosecutor, special victim’s counsel, police legal advisor, senior policy attorney, military magistrate and special assistant U.S. attorney. Von is a Force Science Advanced Specialist and graduate of the FLETC Police Legal Advisors Training Program. He holds a bachelor’s in Crime and Delinquency Studies, a master’s in Criminal Justice Administration, a law degree (J.D.), and a master’s in law post-graduate degree (LL.M.). As an Army Judge Advocate (Retired), Von was recognized as police practices, investigations and use of force legal expert; he supported some of the Pentagon’s top attorneys and drafted DoD and Army use-of-force policy.