Research Output
2026
This study tested whether AI-generated images of police officers can serve as reliable and consistent visual stimuli in social science research, specifically for studying how people perceive officers of different races, genders, and body types. In a nationally representative U.S. sample, participants accurately identified the intended characteristics in each AI-created profile and responded to them in ways consistent with established research on social perception, rating muscular officers more favorably and responding more negatively to officers with higher body weight. The results support AI-generated images as a transparent, reproducible, and scalable tool for researchers who need controlled visual stimuli in experiments about policing and related topics.
This brief responds to a published commentary raising methodological concerns about a 2025 ALERRT study on law enforcement officer mortality. The authors address questions about how occupation is recorded in mortality data and the potential for statistical bias, explaining the reasoning behind their original analytical decisions. They reaffirm that the study was descriptive rather than causal and offer additional comparisons to further contextualize the findings, noting that the work provides a valuable baseline for understanding officer mortality that future studies can build upon.
This study measured what the general public thinks law enforcement officers should do when responding to active shooter events, using two national samples in which participants evaluated more than 15,800 fictional scenarios depicting different officer decisions. Law enforcement officers are most influenced by active threat cues like gunfire or injured victims, but citizens based their judgments primarily on the location of the event, strongly supporting immediate police entry in schools and at parades while being more accepting of a delayed response in settings like large shopping malls. These findings suggest that public expectations and law enforcement training may not always align, which has important implications for police legitimacy and community trust in the aftermath of high-profile events.
This experiment showed short video clips of a police encounter to nearly 1,000 civilians and 744 law enforcement officers, with the clips varying in the type of force used, either a punch or a takedown, as well as the races of the officer and the suspect. Both civilians and officers consistently rated the takedown as more professional and appropriate than the punch, with takedown officers receiving excellent ratings roughly 15 to 25 percentage points more often across both groups. The race of the officer or suspect did not significantly affect judgments in either group. The findings highlight that perceptions of police force are shaped heavily by how the force looks, not just whether it is legally justified, underscoring the importance of both technique and appearance in public and professional evaluations.
2025
Prompted by the deadly New Year’s Day 2025 truck attack on Bourbon Street in New Orleans that killed 14 people, this report examines vehicle-based attacks in the United States using data from the ALERRT Active Attack dataset. Although vehicle attacks make up only a small percentage of all active attacks, they result in significantly more injuries than attacks involving other weapons and are increasingly associated with terrorist organizations. The report outlines patterns in U.S. vehicle-based attacks from 2000 to 2025 and offers practical prevention recommendations, including the strategic placement of physical barriers at crowded public events.
This study examined fitness and health data from 66 male law enforcement officers in Texas to better understand the relationship between physical fitness and risk of heart disease and metabolic illness. Officers with higher cardiorespiratory and muscular fitness had lower insulin resistance, which is a key marker for metabolic disease, while those with higher body fat showed greater levels of inflammation and insulin resistance. The results reinforce that maintaining physical fitness and a healthy body composition are important tools for protecting law enforcement officers from serious long-term health problems.
Using data from the National Occupational Mortality Surveillance program covering more than 15,000 law enforcement officer deaths from 2020 to 2023, this study provides one of the most comprehensive pictures to date of when, why, and among whom officers die. Law enforcement officers showed higher overall death rates compared to the general working-age population, with heart disease, cancer, suicide, and COVID-19 among the leading causes of death for male officers, and cancer being the leading cause for female officers. These findings highlight the urgent need for targeted prevention efforts addressing cardiovascular health, cancer screening, and mental health support within law enforcement.
This study examined the relationships between fitness, body composition, physiological stress, and cardiovascular disease risk among 97 career male firefighters. Firefighters with better cardiorespiratory fitness, greater muscular strength, and healthier body composition had lower markers of insulin resistance, inflammation, and oxidative stress, all of which are linked to heart disease. Notably, salivary stress biomarkers alone were not significantly associated with cardiovascular risk factors, suggesting that fitness and body composition play a more direct role in protecting firefighters’ heart health than stress hormones measured in isolation.
This study followed career firefighters from the Kyle Fire Department as they transitioned from the traditional 24-hours-on/48-hours-off schedule to a rotating schedule offering longer recovery periods between shifts. Over seven months, firefighters on the new schedule showed significantly lower cortisol levels (a key stress hormone), improved sleep quality, and better overall quality of life. The findings suggest that giving firefighters more time to recover between shifts may meaningfully reduce the physical and mental toll of the job.
This study reviewed articles published in 18 of the top-ranked criminology and criminal justice journals to assess how often researchers apply statistical significance tests without meeting the basic requirement of random selection or random assignment. Nearly three-quarters of the reviewed articles used these tests inappropriately, and most researchers focused on whether results were statistically significant rather than on whether they were practically meaningful. The authors call for better statistical training in graduate education, reform of publishing standards, and greater use of exploratory research methods to strengthen the quality of evidence informing criminal justice policy.
This study compared the stress responses of 54 participants who either exercised alone or combined exercise with a virtual reality active shooter training drill. Both groups showed increases in biological stress markers, but those who experienced the combined physical and mental challenge reported significantly higher anxiety in the aftermath. The study also found that female participants showed lower stress biomarker responses than male participants overall. These findings suggest that mental stress, such as that encountered in high-stakes training scenarios, adds meaningfully to perceived anxiety beyond what physical exertion produces on its own.
2024
This study surveyed 526 U.S. law enforcement officers to see whether beliefs and practices around interviewing and interrogation have changed over the past two decades, comparing results to a landmark 2007 survey. The findings show real progress: more than half of interrogations are now recorded on video, compared to fewer than one in ten in 2007, and officers today are much more likely to acknowledge that false confessions happen. These results suggest that law enforcement has been moving in a more science-informed direction when it comes to questioning practices, even though the exact reasons for that shift remain unclear.
Researchers tested whether the phase of the menstrual cycle affects common stress and immune markers in 17 female participants by measuring saliva and vital signs across each phase of their cycle, both morning and afternoon. No significant differences were found based on menstrual cycle phase alone for any of the markers measured. However, time of day did matter, as certain stress markers were higher in the afternoon while immune markers were stronger in the morning. These findings are important for researchers who rely on these biological markers when studying female participants, as controlling for time of day may be necessary to ensure accurate results.
How do conspiracy theories affect the explanation of active shooter events? After confusing and tragic events like active attacks, the public can be more vulnerable to conspiratorial thinking. Two main themes are identified: False flag and Hypothesized reasoning. Results show that many posts following the attack in Uvalde tried to casually explain what happened. But how do these theories affect the people involved in these events?
When discussing options for protecting the safety of those in schools from active attacks, one of the most controversial options is to arm teachers. Without any research to support its efficacy, more than half of the U.S. has authorized policies to arm teachers. The public opinion for this is incredibly divided, but what do the responding police officers think of changes like these? Ten subthemes were identified and were grouped into three larger categories: value of armed teachers, training, and other considerations. Results and implications are discussed further.
The main benefit of scenario-based training is to create realistic and stressful situations for trainees. Recently, departments have started to use virtual reality (VR) to also create scenario training for officers. The aim of this study is to explore whether virtual reality can also induce stress in the same ways an in-person scenario can. Salivary markers of stress were collected before and after a participant experienced either the VR or the in-person scenario. Results were compared and overall stress responses were shown to be similar, thus further implications for training are discussed.
The ingestion of L-theanine and L-tyrosine has been shown to reduce salivary stress markers and improve cognitive performance. This study aims to take a closer look at if that is true while performing a mental stress challenge in virtual reality. Participants were randomly assigned doses or placebo, then performed a virtual reality active shooter training drill. Saliva samples were taken before and after the drill and results were compared. It was found that L-theanine and L-tyrosine did not affect the markers of stress but could impact cognitive performance.
Virtual reality based active shooter training drills have been shown to induce stress in participants, but how does caffeine consumption affect these results? Caffeine can result in better physical and cognitive performance, so could it perform similarly in a virtual reality situation? Participants were randomly assigned caffeine or a placebo, and saliva samples were taken before and after performing a mental stress task in a virtual reality active shooter scenario. Results show that caffeine consumption increased levels of
α-amylase after performing the mental stress task.
A previous study looking into the effects of an officer’s use of vulgar language during use of force is elaborated on further. Originally, the lack of audio in videos shown during the study was highlighted as a limitation. Now, audio was added over each video condition showing use of force, and the study was replicated. Results proved to be similar, showing that public perception of use of force is affected by the use of profanity by the officer. With the presence of vulgar language, regardless of if only read or heard, being perceived as less reasonable.
2023
Firefighters are often diagnosed with cardiometabolic disease, which is linked to multiple risk factors. This study looks into how markers of oxidative stress, inflammation, and insulin resistance can also have information vital to cardiometabolic disease risk. Multiple fitness metrics were taken from firefighters of various years of experience, and the results show an importance of a strong cardiorespiratory fitness and low waist circumference could reduce the markers of cardiovascular disease.
Police, military, and firefighters often experience life-threatening situations. These individuals are trained to use slow breathing techniques while encountering these stressful situations but there is no evidence that tests the effects of these techniques in virtual reality active shooter drills. This study measures biomarkers of stress in response to being assigned one of two slow breathing methods or normal breathing. It is shown that both slow breathing methods resulted in much lower stress markers when compared to normal breathing practices.
If there is an active threat to the public, would police officers wait for more officers to arrive before approaching? This study gathered 796 officers from over 43 states and presented various hypothetical attack situations. Respondents were 14 to 80 times more likely to agree with the hypothetical officer’s decision to approach an attack immediately if a driving force was present. Driving force typically includes things like gunfire or injured victims. If there is an ongoing threat, law enforcement agreed with the public that officers should immediately enter.
Can the type of door lock have an impact on someone’s ability to quickly and accurately secure? This study assessed two types of door locks, one that used a push button from the inside to lock the door and another that required a key to activate the lock. Results showed that simple, push-button door locks can be secured with fewer errors and faster than a keyed door lock. Policy recommendations are included.
2022
Active shooter events occurring in schools generate widespread public concern and a demand to “do something.” One such policy that has gained traction following the 2018 shooting in Parkland, FL is arming teachers. This study used a nationally drawn sample of law enforcement. Ultimately, we found that law enforcement overwhelmingly supports armed teacher policies, but the support is contingent upon concerns related to training.
This project utilized a nationally drawn sample of law enforcement officers to answer questions regarding their attitudes about armed teacher policies. Law enforcement officers provided insights on their attitudes regarding the capabilities of armed teachers, training considerations, as well as firearm and proficiency certification policies. This project utilized a nationally drawn sample of law enforcement officers to answer questions regarding their attitudes about armed teacher policies. Law enforcement officers provided insights on their attitudes regarding the capabilities of armed teachers, training considerations, as well as firearm and proficiency certification policies.
Virtual reality (VR) has emerged as a training tool for law enforcement. While VR is expected to provide a stressful environment for law enforcement to train, little is known about the acute stress response from VR exposure. This study examined the impact of participating in a VR-based active shooter scenario on markers of physiological stress using salivary based measures of stress (e.g., alpha-amylase and secretory immunoglobulin-A [SIgA]). Participating in the VR active shooter scenario resulted in an increase in salivary stress markers.
Active shooter events have driven police to change how they respond to events where an attacker is actively engaged in killing civilians. This paper examines these changes through the lenses of Normal Accident Theory (NAT) and Resilience Engineering (RE). Our results show a police officer is shot in one out of every six active shooter events in the United States. We apply RE to better understand how these shootings occur so that police can improve their ability to anticipate, monitor, and respond during these attacks.
Active-shooting events have become a big topic for many, including practitioners, researchers, and the media. With so many points of view, there is usually some confusion around what exactly some of the defining characteristics of these events are. The purpose of this paper is to explore and elaborate more to define these cases with recorded examples. Databases that exist are discussed as well, along with their inclusion criteria.
A stronger cardiorespiratory fitness level is associated with lower oxidative stress and cardiovascular disease. Yet this correlation has not been studied in firefighters. This study examines firefighters with higher and lower cardiorespiratory levels and their corresponding risk for cardiovascular disease. It was found that high fitness firefighters show significantly lower markers of cardiovascular disease risk and should maintain high cardiorespiratory fitness.
Does an officer’s use of profanity affect how the public responds and reacts to a use of force incident? This study examines two scenarios that show excessive language or a lack of language. The results from 234 responses show that the people considered the exact same video with excessive language to be less reasonable. Possible policy discussions are included due to police officer language can affect civilian perception.
2021
Police frequently engage in high-stress situations that increase a variety of physiological and psychological stress markers. The current study examined differences in male and female salivary and blood markers of stress in response to an active shooter training drill that involved professional actors playing the role of one gunman and four victims. Thirty-one participants took part in the training drill. Blood and saliva samples were collected prior to and following the 50-second training drill. Results revealed increases in stress levels for both male and female participants. However, four of the seven stress markers were lower in female participants compared to male participants.
Use-of-force decisions must often be made in a matter of seconds (or less). The presence of a weapon may impact this decision-making process. Therefore, the speed and accuracy of weapon identification is especially important in use-of-force scenarios. The current study examined whether a brief vision-training program could increase the speed and accuracy in which participants identify an object as a gun in a use-of-force scenario. Results revealed that the participants who received the training were about 16 percent faster and made about 33 percent less errors when identifying the object compared to the participants who did not receive the training. These findings suggest that a simple vision-training program can significantly improve participants’ ability to correctly identify the presence of a firearm in a dynamic use-of-force scenario.
Police are sometimes required to conduct searches for hostile suspects in low light conditions. Police with routinely use a flashlight to help with their search. This study evaluated three of the most commonly taught flashlight tactics to assess if any could reduce the likelihood of a police officer being shot by a hostile suspect. Ultimately, the study found the Dagger technique reduced the likelihood that participants playing the role of a hostile suspect would successfully shoot the officer in a controlled setting.
Responses to active shooter events in our communities have continued to improve over the years. First responder organizations have used training to be better prepared for these disasters. Yet, there are still problems that can arise when responding. The purpose of this study is to analyze the recommendations given in after-action reports of these high-casualty active shooter events to try and identify improvements that can be made by first responders. Three main points are identified and discussed on a more effective response to these events.
2020
The 21-foot rule is taught in training across the country to police officers as either a) the minimum distance that a suspect can cross and attack an officer with a knife before the officer can draw and fire his or her weapon, or b) a safe distance to deal with potentially dangerous suspects armed with knives. This article reports the results of four studies designed to test the adequacy of the 21-foot rule in practice. Results do not support the idea that 21 feet is a safe distance for an officer to stop a charging suspect. Further, having officers move while drawing and firing their weapon, as opposed to remaining stationary, may increase officer safety in these situations.
Although there has been much research on various aspects of active shooter events, little attention has been given to the factors related to the number of people shot or killed in such events. The current study explored these factors. Results generally revealed that as the number of weapons brought to the scene increased, the number of people shot also increased, and this effect was larger for the number of rifles compared to other weapons. Weapon type and number had a smaller impact on the number of people killed than on the number of people shot. Schools were estimated to have one to two fewer people shot than other location types. Further, more recent attacks were estimated to have about one fewer person shot and one fewer person killed. Lastly, events in which potential victims stopped the attacker had the fewest estimated number of people shot.
Police often encounter high-stress situations, such as high-speed chases and other suspect conflicts. The current study examined changes in salivary and blood markers of stress in response to an active shooter training drill. Thirty-one participants took part in the training drill, which included professional actors playing the role of one gunman and four victims. Blood and saliva samples were collected from participants prior to and following the 50-second training drill. Results suggest that a short duration active shooter training drill can increase both blood and salivary marker of stress.
2019
The Columbine High School shooting that occurred on April 20, 1999 changed how law enforcement prepare for active attacks. Training centers were created in response to the need for this specific type of training, including the Advanced Law Enforcement Rapid Response Training (ALERRT) Center, which was formed in 2002 and named the national standard in active shooter training by the Federal Bureau of Investigation (FBI) in 2013. Since then, ALERRT has trained over 130,000 first responders from over 9,000 agencies. The current article describes how active shooter training has changed in the wake of the Columbine shooting.
Solo officer response has become a new trend in active shooter response. The current study evaluates two commonly taught solo officer techniques (the peek and the push) for clearing rooms to determine whether the technique affects the shooting accuracy of the suspect. During a peek entry, the officer keeps as much of his or her body in the hallway, allowing only the head, shoulders, arms, and weapon into the room. Conversely, the officer enters completely into the room when conducting a push entry. An experiment was conducted with 165 student participants playing the role of the suspect. Armed with a training pistol, participants were randomly assigned to a room entry with an officer using either the peek or push technique. Findings suggest limited differences in suspect shooting accuracy between the peek vs. push method of room entry, although officers in the peek condition were moderately more likely to be shot in the head with the training pistols. Findings also suggest that suspects in the push entry are more likely to shoot before the officer than suspects in the peek entry.
2017
The current article provides an in-depth examination of 105 active shooter events (ASEs) in the workplace that occurred from 2000-2015, which include three main categories: factories and warehouses (26), offices (29), and retail locations (50). Overall, 619 people were shot, and 282 people were killed in ASEs at businesses during this period. Attacks were more likely to occur during standard business hours, with a spike at 7pm. In all but two cases, the ASE involved a single shooter. Most (55%) of the events ended before police arrival. By contrast, 45 percent of the ASEs ended after police arrival. To promote a safe work environment, business owners and management may consider (1) utilizing a systematic strategy to detect, assess, and manage individuals that may pose a threat to others (threat assessment), (2) training employees how to respond effectively to ASEs, and (3) making physical security changes to buildings (access control).
Conducting building searches and room entries can place law enforcement officers in danger. The purpose of this study was to examine whether throwing everyday objects at suspects could improve officer safety by distracting the suspect. The study involved an experiment using 113 participants playing the role of a suspect hiding in the “blind” corner of a room facing the door. The research team member playing the officer either made a traditional room entry or had another team member throw a chair into the room before making the traditional room entry. Throwing a chair distracted the participant suspects by slowing down their reaction time, although it did not affect their shooting accuracy. In addition, about one third of participants fired at the chair before officers entered the room. If an officer must conduct a room entry, throwing a chair or other plainly visible object might save the officer’s life.
2011
Decisions made by police officers are typically judged according to a reasonableness standard. This standard is based on what a well-trained, sensible officer would do in a particular situation. The current article used an experiment to assess the reasonableness of an officer’s response to an armed suspect using 30 participant “suspects” and 24 officers. Each officer in the experiment, with their gun drawn and aimed at a suspect, was presented with an armed suspect who was not initially aiming at the officer. The suspect either shot at the officer or surrendered. Reaction times were assessed, revealing that officers fired at the same time or later than the suspects 61 percent of the time. These results suggest that, in this scenario, officers cannot reasonably be expected to shoot before the suspect raises his or her gun and fires. Therefore, officers should avoid situations like the one depicted in the scenario, where they are without cover and distance when facing an armed suspect.
Contents
- Replicate (actually, improve) on https://alerrt.org/reading
- Include summaries like on the current page
- Include things other than peer-reviewed pubs – white papers, AARs, anything we do
- Create infographics??
- Links to preprints for articles under review. These would be replaced when published and moved to the publication page