Right-to-Carry Laws and Firearm Workplace Homicides: A Longitudinal Analysis (1992-2017)

How firearm legislation impacts firearm mortality internationally: A scoping review

Background

The literature on gun violence is broad and variable, describing multiple legislation types and outcomes in observational studies. Our objective was to document the extent and nature of evidence on the impact of firearm legislation on mortality from firearm violence.

Methods

A scoping review was conducted under PRISMA-ScR guidance. A comprehensive peer-reviewed search strategy was executed in several electronic databases from inception to March 2024. Grey literature was searched for unpublished sources. Data were extracted on study design, country, population, type of legislation, and overall study conclusions on legislation impact on mortality from suicide, homicide, femicide, and domestic violence. Critical appraisal for a sample of articles with the same study design (ecological studies) was conducted for quality assessment.

Findings

5057 titles and abstracts and 651 full-text articles were reviewed. Following full-text review and grey literature search, 202 articles satisfied our eligibility criteria. Federal legislation was identified from all included countries, while state-specific laws were only reported in studies from the U.S. Numerous legislative approaches were identified including preventative, prohibitive, and more tailored strategies focused on identifying high risk individuals. Law types had various effects on rates of firearm homicide, suicide, and femicide. Lack of robust design, uneven implementation, and poor evaluation of legislation may contribute to these differences.

Interpretation

We found that national, restrictive laws reduce population-level firearm mortality. These findings can inform policy makers, public health researchers, and governments when designing and implementing legislation to reduce injury and death from firearms.

Funding

Funding is provided by the Strategy for Patient-Oriented Research (SPOR) Evidence Alliance and in part by St. Michael's Hospital, University of Toronto.

Scoping review registration

Open Science Framework (OSF): https://osf.io/sf38n.

The effect of stand-your-ground laws on student achievement

Objectives

To examine how "stand-your-ground" (SYG) laws affect children's academic performance.

Methods

We analyze 2008-2018 nationwide school district-level math and reading/language arts (RLA) test scores for 3rd-8th grade students combined with information on SYG laws by state and year. We implement two estimation approaches-two-way-fixed effects and group-time average treatment effects-and conduct analyses stratified by student race (Black, White) and area income level.

Results

We find negative effects of SYG on math achievement among all students using both estimation approaches (-0.0377 standard deviation decline, p < 0.001 and -0.0493, p < 0.001). We find adverse effects of SYG on math among White students (-0.0315, p = 0.001 and -0.0312, p = 0.08) and among students in low-income districts (-0.0616, p < 0.001 and -0.0903, p < 0.001). The precision of estimates for the effect on math scores among Black students varies across approaches (-0.0666, p = 0.05, -0.0444, p = 0.48). We estimate negative effects of SYG on RLA achievement in only a subset of models.

Conclusions

Our findings suggest SYG laws adversely affect math performance among 3rd-8th grade students.

Policy implications

These findings underscore the importance of additional work to understand and quantify the relationship between the nation's gun policies and children's academic performance.

Trends in workplace homicides in the U.S., 1994-2021: An end to years of decline

Workplace and non-workplace homicides in the United States (U.S.) have declined for over 30 years until recently. This study was conducted to address the change in trends for both workplace and non-workplace homicides and to evaluate the homogeneity of the change in workplace homicides by specified categories. Joinpoint and autoregressive models were used to assess trends of U.S. workplace and non-workplace homicides utilizing surveillance data collected by the Bureau of Labor Statistics and the Federal Bureau of Investigation from 1994 through 2021. Both workplace and non-workplace homicides decreased significantly from 1994 through 2014. Workplace homicides showed no significant trend from 2014 through 2021 (p = 0.79), while non-workplace homicides showed a significant average annual increase of 4.1% from 2014 through 2020 (p = 0.0013). The large decreases in the trend of workplace homicides occurring during a criminal act, such as robbery, leveled off and started to increase by the end of the study period (p < 0.0001). Declines in workplace homicides due to shootings also leveled off and started to increase by the end of the study period (p < 0.0001). U.S. workplace and non-workplace homicide rates declined from the 1990s until around 2014. Trends in workplace homicides varied by the types of the homicide committed and by the type of employee that was the victim. Criminal-intent-related events, such as robbery, appear to be the largest contributor to changes in workplace homicides. Researchers and industry leaders could develop and evaluate interventions that further address criminal-intent-related workplace homicides.

State Firearm Laws and Rate of Assault-Related Firearm Death

BACKGROUND

Studying firearm-related mortality is important to reduce preventable firearm death in the US. This study aims to determine the relationship between firearm laws and assault death with firearms.

STUDY DESIGN

This ecologic study used public data from the CDC Wide-Ranging Online Data for Epidemiologic Research on decedents age 18 years or older who died from assault with firearms between 2009 and 2018 in all 50 states and Washington, DC. The outcomes were the rate of mortality per 100,000 persons from assault death by firearm used. Exposures of interest included the presence of 7 state firearm laws extracted from the RAND State Firearm Law Database. Welch's t tests were performed to compare mean mortality rate in states with each firearm law to states without each law.

RESULTS

There were 114,945 deaths from assault with firearms from 2009 to 2018. States with "stand your ground" laws had a higher assault mortality rate from all firearms and from other/unspecified firearms than states without stand your ground laws (p = 0.026; p = 0.023). States with background checks for private sales of handguns and long guns had a lower assault mortality rate from handguns and rifles, shotguns, and large firearms, respectively, than states without either law (p = 0.019; p = 0.030).

CONCLUSIONS

Stand your ground laws are correlated with a higher rate of gun-related assault death, but background checks on private sales are correlated with a lower rate. Future studies should elucidate the specific pathways by which state laws reduce, or fail to reduce, firearm-related assault death.

Association of state-level factors with rate of firearm-related deaths

BACKGROUND

Over 48,000 people died by firearm in the United States in 2021. Firearm violence has many inciting factors, but the full breadth of associations has not been characterized. We explored several state-level factors including factors not previously studied or insufficiently studied, to determine their association with state firearm-related death rates.

METHODS

Several state-level factors, including firearm open carry (OC) and concealed carry (CC) laws, state rank, partisan lean, urbanization, poverty rate, anger index, and proportion of college-educated adults, were assessed for association with total firearm-related death rates (TFDR). Secondary outcomes were firearm homicide (FHR) and firearm suicide rates (FSR). Exploratory data analysis with correlation plots and ANOVA was performed. Univariable and multivariable linear regression on the rate of firearm-related deaths was also performed.

RESULTS

All 50 states were included. TFDR and FSR were higher in permitless OC and permitless CC states. FHR did not differ based on OC or CC category. Open carry and CC were eliminated in all three regression models due to a lack of significance. Significant factors for each model were: 1) TFDR - partisan lean, urbanization, poverty rate, and state ranking; 2) FHR - poverty rate; 3) FSR - partisan lean and urbanization.

CONCLUSIONS

Neither open nor concealed carry is associated with firearm-related death rates when socioeconomic factors are concurrently considered. Factors associated with firearm homicide and suicide differ and will likely require separate interventions to reduce firearm-related deaths.

KEY MESSAGE

Neither open carry nor concealed carry law are associated with total firearm-related death rate, but poverty rate, urbanization, partisan lean, and state ranking are associated. When analyzing firearm homicide and suicide rates separately, poverty rate is strongly associated with firearm homicide rate, while urbanization and partisan lean are associated with firearm suicide rate.

Invited Commentary: Concealed Carrying of Firearms, Public Policy, and Opportunities for Mitigating Harm

In the last 30 years, 25 US states have relaxed laws regulating the concealed carrying of firearms (concealed-carry weapons (CCW) laws). These changes may have substantial impacts on violent crime. In a recent study, Doucette et al. (Am J Epidemiol. 2023;192(3):342-355) used a synthetic control approach to assess the effects of shifting from more restrictive "may/no-issue" CCW laws to less restrictive "shall-issue" CCW laws on homicides, aggravated assaults, and robberies involving a gun or committed by other means. The study adds to the evidence that more permissive CCW laws have probably increased rates of firearm assault in states adopting these laws. Importantly, this study is the first to identify that specific provisions of shall-issue CCW laws-including denying permits to persons with violent misdemeanor convictions, a history of dangerous behavior, or "questionable character" and live-fire training requirements-may help mitigate harms associated with shall-issue CCW laws. These findings are timely and salient given the recent Supreme Court ruling striking down a defining element of may-issue laws. This thorough study offers actionable results and provides a methodological model for state firearm policy evaluations. Its limitations reflect the needs of the field more broadly: greater focus on racial/ethnic equity and within-state variation, plus strengthening the data infrastructure on firearm violence and crime.

Impact of Changes to Concealed-Carry Weapons Laws on Fatal and Nonfatal Violent Crime, 1980-2019

The United States faces rapidly rising rates of violent crime committed with firearms. In this study, we sought to estimate the impact of changes to laws that regulate the concealed carrying of weapons (concealed-carry weapons (CCW) laws) on violent crimes committed with a firearm. We used augmented synthetic control models and random-effects meta-analyses to estimate state-specific effects and the average effect of adopting shall-issue CCW permitting laws on rates of 6 violent crimes: homicide with a gun, homicide by other means, aggravated assault with a gun, aggravated assault with a knife, robbery with a gun, and robbery with a knife. The average effects were stratified according to the presence or absence of several shall-issue permit provisions. Adoption of a shall-issue CCW law was associated with a 9.5% increase in rates of assault with a firearm during the first 10 years after law adoption and was associated with an 8.8% increase in rates of homicide by other means. When shall-issue laws allowed violent misdemeanants to acquire CCW permits, the laws were associated with higher rates of gun assaults. It is likely that adoption of shall-issue CCW laws has increased rates of nonfatal violent crime committed with firearms. Harmful effects of shall-issue laws are most clear when provisions intended to reduce risks associated with civilian gun-carrying are absent.

Racial Differences in Firearms Used and Autopsies Following Gun Deaths Exist

INTRODUCTION

Disparities in gun violence across race are well documented. Studying these disparities is essential to reduce preventable gun deaths. This study evaluates the relationship between sociodemographic factors and firearms used in gun deaths.

MATERIALS AND METHODS

This retrospective cohort study of firearm mortalities from 2009 to 2018 used the Mortality Multiple Cause-of-Death Public Use Record from the National Center for Health Statistics. The primary outcome was the type of firearm used and the secondary outcome was autopsy status. Factors of interest include race, ethnicity, gender, marital status, age, education, and place of death. Factors significantly associated with outcomes in univariate analyses were included in separate multivariate logistic regression models for assaults, intentional self-harm, and accidents.

RESULTS

A total of 276,127 firearm deaths from 2009 to 2018 were analyzed. Compared to White victims, Black victims were less likely to die from handguns (accident: odds ratio [OR] = 0.70, P < 0.05; self-harm: OR = 0.84, P < 0.001; assault: OR = 0.58, P < 0.001) and rifles, shotguns, or large firearms (accident: OR = 0.30, P < 0.001; self-harm: OR = 0.37, P < 0.001; assault: OR = 0.28, P < 0.001). Black decedents were more likely to undergo autopsy than White decedents (accident: OR = 2.14, P < 0.001; intentional self-harm: OR = 2.02, P < 0.001; assault: OR = 2.02, P < 0.001). Ethnicity, gender, marital status, age, education, and other racial identities were also associated with firearms used and autopsy rates (P < 0.05).

CONCLUSIONS

Differences in firearms used and autopsy rates following gun deaths exist by race, ethnicity, gender, marital status, age, and education. Future studies should investigate the relationship between sociodemographic factors and firearms used and autopsy status following gun deaths.

Public opinion on laws regulating public gun carrying

This study sought to examine public support for gun carrying-related policies from 2019 to 2021, a period encompassing the COVID-19 pandemic and increasing calls for racial and social justice. We conducted the National Survey of Gun Policy in January 2019 and 2021. The surveys were fielded using the NORC AmeriSpeak panel. Respondents indicated support for six policies regulating civilian gun carrying. Analyses, conducted in 2021, incorporated survey weights for nationally representative estimates. There were significant declines in support from 2019 to 2021 for two policies that would expand where civilians can lawfully carry guns: allowing concealed carry when on K-12 school grounds (23% in 2021 vs 31% in 2019) and college/university campuses (27% vs 36%). Support was also significantly lower for requiring concealed carry applicants to pass a test demonstrating safe and lawful use (74% in 2021 vs 81% in 2019). For the two new policies in the 2021 survey, more than half of respondents overall supported prohibiting open carry at demonstrations/rallies (54%) and prohibiting the carry of guns into government buildings (69%). There was lower support among gun owners (39% and 57%, respectively). Since 2019, there has been a decline in support for expanding locations for civilian gun carrying. Support remains high among U.S. adults, including the two-thirds of gun owners, for requiring concealed carry applicants to demonstrate competence in safe and lawful gun use. Our findings in support of a more regulated approach to concealed carry are in direct contrast to state-level shifts eliminating concealed gun carrying regulations.

Officer-Involved Shootings and Concealed Carry Weapons Permitting Laws: Analysis of Gun Violence Archive Data, 2014-2020

About 1,000 civilians are killed every year by a law enforcement officer in the USA, more than 90% by firearms. Most civilians who are shot are armed with a firearms. Higher rates of officer-involved shootings (OIS) are positively associated with state-level firearm ownership. Laws relaxing restrictions on civilians carrying concealed firearms (CCW) have been associated with increased violent crime. This study examines associations between CCW laws and OIS. We accessed counts of fatal and nonfatal OIS from the Gun Violence Archive (GVA) from 2014-2020 and calculated rates using population estimates. We conducted legal research to identify passage years of CCW laws. We used an augmented synthetic control models with fixed effects to estimate the effect of Permitless CCW law adoption on OIS over fourteen biannual semesters. We calculated an inverse variance weighted average of the overall effect. On average, Permitless CCW adopting states saw a 12.9% increase in the OIS victimization rate or an additional 4 OIS victimizations per year, compared to what would have happened had law adoption not occurred. Lax laws regulating civilian carrying of concealed firearms were associated with higher incidence of OIS. The increase in concealed gun carrying frequency associated with these laws may influence the perceived threat of danger faced by law enforcement. This could contribute to higher rates of OIS.

The Revolution Will Be Hard to Evaluate: How Co-Occurring Policy Changes Affect Research on the Health Effects of Social Policies

Extensive empirical health research leverages variation in the timing and location of policy changes as quasi-experiments. Multiple social policies may be adopted simultaneously in the same locations, creating co-occurrence that must be addressed analytically for valid inferences. The pervasiveness and consequences of co-occurring policies have received limited attention. We analyzed a systematic sample of 13 social policy databases covering diverse domains including poverty, paid family leave, and tobacco use. We quantified policy co-occurrence in each database as the fraction of variation in each policy measure across different jurisdictions and times that could be explained by covariation with other policies. We used simulations to estimate the ratio of the variance of effect estimates under the observed policy co-occurrence to variance if policies were independent. Policy co-occurrence ranged from very high for state-level cannabis policies to low for country-level sexual minority-rights policies. For 65% of policies, greater than 90% of the place-time variation was explained by other policies. Policy co-occurrence increased the variance of effect estimates by a median of 57-fold. Co-occurring policies are common and pose a major methodological challenge to rigorously evaluating health effects of individual social policies. When uncontrolled, co-occurring policies confound one another, and when controlled, resulting positivity violations may substantially inflate the variance of estimated effects. Tools to enhance validity and precision for evaluating co-occurring policies are needed.

What to Do When Everything Happens at Once: Analytic Approaches to Estimate the Health Effects of Co-Occurring Social Policies

Social policies have great potential to improve population health and reduce health disparities. Increasingly, those doing empirical research have sought to quantify the health effects of social policies by exploiting variation in the timing of policy changes across places. Multiple social policies are often adopted simultaneously or in close succession in the same locations, creating co-occurrence that must be handled analytically for valid inferences. Although this is a substantial methodological challenge for researchers aiming to isolate social policy effects, only in a limited number of studies have researchers systematically considered analytic solutions within a causal framework or assessed whether these solutions are being adopted. We designated 7 analytic solutions to policy co-occurrence, including efforts to disentangle individual policy effects and efforts to estimate the combined effects of co-occurring policies. We used an existing systematic review of social policies and health to evaluate how often policy co-occurrence is identified as a threat to validity and how often each analytic solution is applied in practice. Of the 55 studies, only in 17 (31%) did authors report checking for any co-occurring policies, although in 36 studies (67%), at least 1 approach was used that helps address policy co-occurrence. The most common approaches were adjusting for measures of co-occurring policies; defining the outcome on subpopulations likely to be affected by the policy of interest (but not other co-occurring policies); and selecting a less-correlated measure of policy exposure. As health research increasingly focuses on policy changes, we must systematically assess policy co-occurrence and apply analytic solutions to strengthen studies on the health effects of social policies.

Impact of ShotSpotter Technology on Firearm Homicides and Arrests Among Large Metropolitan Counties: a Longitudinal Analysis, 1999-2016

Over the past decade, large urban counties have implemented ShotSpotter, a gun fire detection technology, across the USA. It uses acoustic listening devices to identify discharged firearms' locations. We examined the effect of ShotSpotter with a pooled, cross-sectional time-series analysis within the 68 large metropolitan counties in the USA from 1999 to 2016. We identified ShotSpotter implementation years through publicly available media. We used a Poisson distribution to model the impact of ShotSpotter on firearm homicides, murder arrests, and weapons arrests. ShotSpotter did not display protective effects for all outcomes. Counties in states with permit-to-purchase firearm laws saw a 15% reduction in firearm homicide incidence rates; counties in states with right-to-carry laws saw a 21% increase in firearm homicide incidence rates. Results suggest that implementing ShotSpotter technology has no significant impact on firearm-related homicides or arrest outcomes. Policy solutions may represent a more cost-effective measure to reduce urban firearm violence.

Bang for the buck: The impact of political financial contributions on firearm law

BACKGROUND

One hundred thousand Americans are shot annually, and 39,000 die. State laws restricting firearm sales and use have been shown to decrease firearm deaths, yet little is known about what impacts their passage or repeal. We hypothesized that spending by groups that favor firearm restrictive legislation would increase new state firearm restrictive laws (FRLs) and that states increasing these laws would endure fewer firearm deaths.

METHODS

We acquired 2013 to 2018 state data on spending by groups against firearm restrictive legislation and for firearm restrictive legislation regarding lobbying, campaign, and independent and total expenditures from the National Institute on Money in State Politics. State-level political party representation data were acquired from the National Conference of State Legislatures. Mass shooting data were obtained from the Mass Shooter Database of the Violence Project, and firearm death rates were obtained from Centers for Disease Control Wide-ranging Online Data for Epidemiologic Research and Federal Bureau of Investigation Uniform Crime Reporting databases. Firearm restrictive laws were obtained from the State Firearms Law Database. A univariate panel linear regression with fixed effect for state was performed with change in FRLs from baseline as the outcome. A final multivariable panel regression with fixed effect for state was then used. Firearm death rates were compared by whether states increased, decreased, or had no change in FRLs.

RESULTS

Twenty-two states gained and 13 lost FRLs, while 15 states had no net change (44%, 26%, and 30%; p = 0.484). In multivariable regression accounting for partisan control of state government, for-firearm restrictive legislation groups outspending against-firearm restrictive legislation groups had the largest association with increased FRLs (β = 1.420; 95% confidence interval, 0.63-2.21; p < 0.001). States that gained FRLs had significantly lower firearm death rates (p < 0.001). Relative to states with no change in FRLs, states that lost FRLs had an increase in overall firearm death of 1 per 100,000 individuals. States that gained FRLs had a net decrease in median overall firearm death of 0.5 per 100,000 individuals.

CONCLUSION

Higher political spending by groups in favor of restrictive firearm legislation has a powerful association with increasing and maintaining FRLs. States that increased their FRLs, in turn, showed lower firearm death rates.

LEVEL OF EVIDENCE

Epidemiological, level I.

Effects of Laws Expanding Civilian Rights to Use Deadly Force in Self-Defense on Violence and Crime: A Systematic Review

Background. Since 2005, most US states have expanded civilian rights to use deadly force in self-defense outside the home. In most cases, legislation has included removing the duty to retreat anywhere one may legally be, commonly known as stand-your-ground laws. The extent to which these laws affect public health and safety is widely debated in public and policy discourse.Objectives. To synthesize the available evidence on the impacts and social inequities associated with changing civilian rights to use deadly force in self-defense on violence, injury, crime, and firearm-related outcomes.Search Methods. We searched MEDLINE, Embase, PsycINFO, Scopus, Web of Science, Sociological Abstracts, National Criminal Justice Reference Service Abstracts, Education Resources Information Center, International Bibliography of the Social Sciences, ProQuest Dissertations and Theses, Google Scholar, National Bureau of Economic Research working papers, and SocArXiv; harvested references of included studies; and consulted with experts to identify studies until April 2020.Selection Criteria. Eligible studies quantitatively estimated the association between laws that expanded or restricted the right to use deadly force in self-defense and population or subgroup outcomes among civilians with a comparator.Data Collection and Analysis. Two reviewers extracted study data using a common form. We assessed study quality using the Risk of Bias in Nonrandomized Studies of Interventions tools adapted for (controlled) before-after studies. To account for data dependencies, we conducted graphical syntheses (forest plots and harvest plots) to summarize the evidence on impacts and inequities associated with changing self-defense laws.Main Results. We identified 25 studies that estimated population-level impacts of laws expanding civilian rights to use deadly force in self-defense, all of which focused on stand-your-ground or other expansions to self-defense laws in the United States. Studies were scored as having serious or critical risk of bias attributable to confounding. Risk of bias was low across most other domains (i.e., selection, missing data, outcome, and reporting biases). Stand-your-ground laws were associated with no change to small increases in violent crime (total and firearm homicide, aggravated assault, robbery) on average across states. Florida-based studies showed robust increases (24% to 45%) in firearm and total homicide while self-defense claims under stand-your-ground law were more often denied when victims were White, especially when claimants were racial minorities.Author's Conclusions. The existing evidence contradicts claims that expanding self-defense laws deters violent crime across the United States. In at least some contexts, including Florida, stand-your-ground laws are associated with increases in violence, and there are racial inequities in the application of these laws.Public Health Implications. In some US states, most notably Florida, stand-your-ground laws may have harmed public health and safety and exacerbated social inequities. Our findings highlight the need for scientific evidence on both population and equity impacts of self-defense laws to guide legislative action that promotes public health and safety for all.Trial Registration. Open Science Framework (https://osf.io/uz68e).

Gunshot homicides in Denmark 1992-2016

The majority of homicides in the world are caused by firearms and a good understanding of gunshot wounds is important for the forensic pathologist. We have analyzed all 315 homicides by gunshots in Denmark during 1992-2016 with focus on information relevant to forensic pathologists. Of the 1417 homicides in Denmark in 1992-2016, 315 (22.2%) had gunshot trauma as the primary homicide method. During 1992-2016, there has been a significant decrease in the number of gunshot homicides overall, of homicides committed with hunting weapons, and of domestic gunshot homicides. Most victims (70.5%) and offenders (93.7% of homicides with known offenders) were males. Male victims were significantly younger than female victims. Most victims were killed with handguns (43.8%) or shotguns (41.0%). Compared to all other weapons, the victims killed with shotguns had fewer entry wounds, a higher New Injury Severity Score (NISS), and a higher proportion of contact/close-range entry wounds. The head (58.1%) and thorax (46.7%) were often injured, with injuries to the head being more common in contact/close-range entry wounds. The results show that gunshot injuries in homicides are different from suicides and accidents and clearly are affected by the homicide type, the sex of the victim, and the weapon used and that these entities are intertwined. Our findings provide an evidence-based foundation for use in death investigations and for policy development in the area of interpersonal violence.