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Research
Peer-reviewed research on active shooter response, officer stress and performance, use of force decision-making, and public opinion of police.
My research spans two primary areas: policing (with emphases on officer stress and physiology, use of force and decision making, and public opinion) and active shooter preparedness and response. Use the topic and year filters below to narrow the list. Summaries are written for a general audience. For full abstracts and citation information, use the DOI or PDF links.
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Public Opinion & Legitimacy
Striking or grappling? Comparing public and officers' perceptions of police use of force
Journal of Criminal Justice, 103, 102601 (2026)
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.
Officer Stress & Performance
Clarifying methods and interpretations in law enforcement mortality surveillance: Response to Kamal
The Lancet Regional Health - Americas, 53, 101330 (2026)
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.
Public Opinion & Legitimacy
Public opinion and the immediate entry dilemma: A factorial survey experiment on active shooter response
Journal of Criminal Justice, 102, 102578 (2026)
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.
Officer Stress & Performance
Mortality among law enforcement officers in the United States: A population-wide analysis of the National Occupational Mortality Surveillance data, 2020-2023
The Lancet Regional Health - Americas, 52, 101270 (2025)
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.
Officer Stress & Performance
Shift schedule change from 24/48 to 1/3/2/3 improves markers of stress and quality of life in career firefighters
Journal of Occupational and Environmental Medicine (2025)
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.
Officer Stress & Performance
Virtual reality based active shooter training: Added physical stress increases anxiety but not stress biomarkers
Psychoneuroendocrinology (2025)
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.
Other
To what are we inferring? The widespread misuse of inferential testing in the most cited criminology and criminal justice journals
American Journal of Criminal Justice (2025)
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.
Active Shooter Events
Active attacks with motor vehicles: A short report and case study of the 2025 New Year's Day attack in New Orleans, LA
American Journal of Criminal Justice (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.
Officer Stress & Performance
Relationships between physiological stress biomarkers and cardiovascular disease risk factors among career firefighters
Journal of Occupational and Environmental Medicine (2025)
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.
Officer Stress & Performance
Markers of fitness, stress, and cardiometabolic disease risk among law enforcement officers
Journal of Occupational and Environmental Medicine, 67(6), 437-444 (2025)
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.
Officer Stress & Performance
Can a Virtual Reality Training Scenario Elicit a Stress Response Similar to a Realistic Scenario Based Training Scenario?
Applied Police Briefings, 1(3), 17-19 (2025)
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.
Public Opinion & Legitimacy
Oh, @#%$!: A replication and expansion of Martaindale et al. (2024)
Policing: An International Journal (2024)
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.
Decision Making & Use of Force
Interviewing and interrogation practices and beliefs, twenty years later: A national self-report survey of American police
Law and Human Behavior (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.
Active Shooter Events
#FalseFlag: Exploring themes in conspiracy theory tweets regarding the Robb Elementary School active shooter event
Journal of Qualitative Criminology (2024)
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?
Officer Stress & Performance
Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill
Stress, 27(1), 2375588 (2024)
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.
Officer Stress & Performance
Stress response to virtual reality based active shooter training: Impact of caffeine consumption
Psychoneuroendocrinology (2024)
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.
Officer Stress & Performance
Can a virtual reality training scenario elicit similar stress response as a realistic scenario-based training scenario?
Police Quarterly, 27(1), 109-129 (2024)
Scenario-based training relies on realistic, stressful situations to prepare officers for real-world encounters. With more agencies turning to virtual reality systems, this study tested whether a VR scenario produces a comparable stress response to an in-person scenario-based training exercise. Participants completed either the in-person exercise (n=31) or a VR version of the same exercise (n=27), with salivary stress markers measured before and after. Stress responses were similar across the two formats, indicating that VR can serve as a credible alternative when realistic in-person training is not feasible. The results support broader integration of VR into police training programs.
Active Shooter Events
Arm the educators - but not without conditions: A qualitative assessment of law enforcement officers' support for armed teacher policies
Police Practice and Research, 25(4), 473-489 (2024)
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.
Decision Making & Use of Force
A scientific examination of the 21-foot rule
Applied Police Briefs, 1(1) (2024)
This Applied Police Briefs piece distills the original empirical test of the 21-foot rule for a practitioner audience. Across three experiments, the researchers measured how fast a person can cover 21 feet, how quickly officers can draw and fire under both calm and stressed conditions, and how lateral movement affects survivability. The data show that 21 feet is not a safe distance against an edged-weapon suspect, since the suspect can typically close the gap before the officer can respond. Movement substantially improved survivability. The brief calls for replacing the rigid 21-foot rule with training that emphasizes movement and decision-making.
Public Opinion & Legitimacy
Wait for backup or not? How police officers view their role when responding to an active shooter event
Journal of Experimental Criminology (2023)
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.
Officer Stress & Performance
Slow breathing reduces biomarkers of stress in response to a virtual-reality active shooter training drill
Healthcare, 11(16) (2023)
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.
Active Shooter Events
Successfully securing a classroom door in an active shooter event: Examining two types of door locks
Journal of Mass Violence Research (2023)
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.
Officer Stress & Performance
Risk factors for cardiometabolic disease in professional firefighters
Safety and Health at Work, 65(2), 119-124 (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.
Active Shooter Events
What are we talking about? Definitional confusion within mass and active shooting research
Journal of Mass Violence Research, 1(2), 4-16 (2022)
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.
Officer Stress & Performance
Firefighters with higher cardiorespiratory fitness demonstrate lower markers of cardiovascular disease risk
Journal of Occupational and Environmental Medicine (2022)
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.
Public Opinion & Legitimacy
#&$@!!: The impact of swear words on civilians' perception of officer use of force
Police Quarterly, 26(2), 194-212 (2022)
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.
Officer Stress & Performance
Virtual reality based active shooter training drill increases salivary and subjective markers of stress
Yale Journal of Biology and Medicine, 95(1), 105-113 (2022)
Officers regularly face dangerous, life-threatening situations on the job. This study tested whether a brief virtual reality active shooter drill could trigger a measurable physiological stress response, and whether men and women respond differently. Twenty-nine participants completed a roughly 50-second VR scenario while saliva was sampled four times before and after. The drill produced significant increases in salivary stress markers, and women showed lower cortisol and uric acid concentrations than men. The findings suggest VR is a viable, low-cost training tool for inducing realistic stress in tactical occupations.
Public Opinion & Legitimacy
Armed and considered capable? Law enforcement officers' attitudes about armed teacher policies in the United States
Crime Prevention and Community Safety, 24(2) (2022)
Several U.S. states have adopted policies allowing teachers to be armed at school, with little input from the law enforcement community on whether the policies make schools safer. This study used a 2020 nationwide survey of officers spanning many job duties, agency types, and community settings to assess where law enforcement actually stands. Respondents broadly supported armed teacher policies, but most expressed strong reservations about whether teachers receive enough training to respond effectively during an active shooter event. The results offer policymakers and school administrators a clearer picture of officer perspectives, and underscore training as a pivotal condition for any such policy.
Active Shooter Events
Should firearms be allowed in K-12 public schools? An analysis of law enforcement's perceptions of armed teacher policies
Security Journal (2022)
Policies allowing teachers to carry firearms at school have spread since the 2018 Parkland shooting, despite limited public support and almost no input from law enforcement. Drawing on a national sample of officers, this study found that law enforcement broadly supports armed teacher policies, but conditions that support on adequate training. School resource officers and supervisors were noticeably less likely to favor the policy than patrol officers. The findings highlight an important divide between policy momentum and the views of those most directly involved in school safety.
Decision Making & Use of Force
An evaluation of light positioning on suspect accuracy in low light environments
Justice Evaluation Journal, 5(1) (2021)
Police searches in low-light environments often rely on flashlights, but the standard techniques taught in training have not been rigorously tested. This randomized controlled trial with 236 participants compared three commonly taught flashlight tactics to see whether any meaningfully reduced the chance of an officer being shot by a hidden suspect. The Dagger technique significantly lowered the likelihood that participants playing the role of a hostile suspect could successfully shoot the officer. The finding has direct implications for how officers should be trained to operate in low-light situations.
Officer Stress & Performance
Women demonstrate lower markers of stress and oxidative stress during active shooter training drill
Comprehensive Psychoneuroendocrinology, 6, 100046 (2021)
Officer stress takes a measurable toll on long-term cardiovascular health, but most studies assume the response looks the same in men and women. This study compared salivary and blood stress markers in 31 participants (15 men, 16 women) immediately before and after a roughly 50-second active shooter training drill. Women showed lower markers of stress and oxidative stress than men, suggesting acute stress affects the sexes differently. The findings imply that interventions and training stress protocols may need to be tailored by sex rather than designed uniformly.
Decision Making & Use of Force
Improving the accuracy of firearm identification in a dynamic use of force scenario
Police Quarterly, 24(1), 104-130 (2021)
In split-second use of force decisions, mistakes about whether a suspect is holding a gun can be tragic. This randomized experiment tested whether a brief deliberate-practice training program could improve officers' speed and accuracy at identifying firearms in a dynamic scenario. Eighty-seven participants completed a pretest, a 20-minute training intervention, and a posttest, with eye movements tracked throughout. The trained group made about one-third the errors of the control group and visually located the object roughly 16% faster. The results show that even short, focused training can substantially sharpen officer perception in shoot/no-shoot situations.
Decision Making & Use of Force
A scientific examination of the 21-foot rule
Police Practice & Research, 22(3), 1314-1329 (2021)
This study put the long-standing 21-foot rule to an empirical test. Across three experiments, the researchers measured how fast a person can cover 21 feet, how quickly officers can draw and fire under both calm and stressed conditions, and how lateral movement affects survivability. The results show that 21 feet is not a safe distance: a charging suspect with an edged weapon can typically reach an officer faster than the officer can respond. Movement substantially improved officer survivability. The study argues that the 21-foot rule is inadequate as a fixed standard and that movement should be emphasized in training.
Officer Stress & Performance
Active shooter training drill increases blood and salivary markers of stress
International Journal of Environmental Research and Public Health, 17(14) (2020)
This study tested whether a short, realistic active shooter training drill produces a measurable physiological stress response. Thirty-one participants completed a roughly 50-second drill featuring professional actors as a gunman and four victims, with blood and saliva collected before and after. The drill produced significant increases in epinephrine and salivary stress markers (alpha-amylase and SIgA), with norepinephrine increases approaching significance. The findings confirm that even brief training drills generate genuine stress responses, with implications for how repeated exposure may affect long-term cardiometabolic health in officers and military personnel.
Active Shooter Events
Correlates of the number shot and killed in active shooter events
Homicide Studies, 25(4), 335-360 (2020)
Active shooter events have been studied from many angles, but only one prior study had tried to identify what factors predict how many people are injured or killed. This study compiled data on a large set of active shooter events and tested a wide range of incident, attacker, and response characteristics. The analysis found that several factors, including weapon type, location characteristics, and law enforcement response, were significantly associated with casualty counts. The results provide a more complete picture of which factors drive the human toll of these events and where prevention and response efforts may have the greatest effect.
Active Shooter Events
Peek or push: An examination of two types of room clearing tactics for active shooter event response
Journal of Police Emergency Response, 9(3) (2019)
When officers respond to an active shooter, room clearing tactics can put them in immediate danger. This study compared two competing approaches: a slow 'peek' that lets officers visually scan a room before entering, and a faster 'push' that prioritizes momentum and surprise. Using a controlled experimental design, the researchers measured how each tactic performed against a simulated suspect. The results favored one approach for officer survivability, with direct implications for how patrol officers should be trained to enter and clear rooms during ongoing attacks. The findings inform tactical decisions during the most dangerous phase of an active shooter response.
Active Shooter Events
The evolution of active shooter response training protocols since Columbine: Lessons from the advanced law enforcement rapid response training center
Journal of Contemporary Criminal Justice, 35(3) (2019)
The 1999 Columbine attack fundamentally changed how American law enforcement prepares for active shooter events. This commentary traces how response training protocols have evolved in the two decades since, drawing on the experience of the Advanced Law Enforcement Rapid Response Training (ALERRT) Center. The piece reviews how doctrines around containment, immediate entry, single-officer response, and integrated rescue have shifted as the field has accumulated evidence from real events and field research. It also identifies gaps where further research and training development are still needed. The article serves as a roadmap for understanding how policing has adapted, and where it still needs to go.
Decision Making & Use of Force
Throwing a chair could save officers' lives during room entries
International Journal of Police Science and Management, 19(2) (2017)
Officers performing room entries to apprehend suspects have been shot in the doorway because the suspect has the time advantage. This study tested whether throwing an everyday object into the room as a distraction could slow a hostile suspect's reaction time enough to give the officer a survivable advantage. A randomized experiment with 113 participants used both Bayesian and frequentist analyses to evaluate the effect. Simple distraction techniques, including throwing a chair, reliably slowed suspect reaction times, suggesting officers can buy critical time during high-risk entries. The technique offers a low-cost addition to room-entry tactics.
Active Shooter Events
Active shooter events in the workplace: Findings and policy implications
Journal of Business Continuity and Emergency Planning, 11(1) (2017)
Workplaces are generally seen as safe, but active shooter incidents at businesses do occur, and leadership often makes hurried security decisions in their wake. This study compiled data on workplace active shooter events to give business leaders an empirical basis for those decisions. The findings detail patterns in attacker characteristics, weapons, response times, and casualty outcomes specific to workplace settings. From these patterns, the authors derive concrete policy recommendations for businesses on prevention, preparation, and response. The paper provides a research-based foundation for workplace security planning rather than reactive policy.