What Do We Know About the Association Between Firearm Legislation and Firearm-Related Injuries?

Abstract

Firearms account for a substantial proportion of external causes of death, injury, and disability across the world. Legislation to regulate firearms has often been passed with the intent of reducing problems related to their use. However, lack of clarity around which interventions are effective remains a major challenge for policy development. Aiming to meet this challenge, we systematically reviewed studies exploring the associations between firearm-related laws and firearm homicides, suicides, and unintentional injuries/deaths. We restricted our search to studies published from 1950 to 2014. Evidence from 130 studies in 10 countries suggests that in certain nations the simultaneous implementation of laws targeting multiple firearms restrictions is associated with reductions in firearm deaths. Laws restricting the purchase of (e.g., background checks) and access to (e.g., safer storage) firearms are also associated with lower rates of intimate partner homicides and firearm unintentional deaths in children, respectively. Limitations of studies include challenges inherent to their ecological design, their execution, and the lack of robustness of findings to model specifications. High quality research on the association between the implementation or repeal of firearm legislation (rather than the evaluation of existing laws) and firearm injuries would lead to a better understanding of what interventions are likely to work given local contexts. This information is key to move this field forward and for the development of effective policies that may counteract the burden that firearm injuries pose on populations.

Keywords: death; firearms; homicide; legislation; suicide; weapons; wounds and injuries.

Figure 1.

Process of selecting studies examining the effects of firearm-related laws with firearm homicides, suicides, and unintentional deaths.

Figure 2.

Summary of results from studies examining the effects of laws targeting firearms use (shall issue or right to carry laws, bans on carrying laws, and castle doctrine and stand your ground laws) on homicides and firearm homicides. We present only a single estimate from each study because of space limitations. We selected the estimates from models that, to our consideration, included the most important model specifications. We present the results from studies with comparable results in terms of percent change in firearm deaths (when not provided, we calculated the percent change if there was available information for calculations). Stand your ground laws are presented with castle doctrine laws. The estimate in Grambsch (37) represents the percent annual change in the rate of homicides in the postlaw period compared with the prelaw period. CI, confidence interval.

Figure 3.

Summary of results from studies examining the effects of firearm laws (firearms sales, firearms ownership, firearms storage regulations, laws targeting specific firearms and ammunition, sentences and punishment for gun offenders, and combinations of laws being simultaneously implemented) on homicides and firearm homicides. We present only a single estimate from each study because of space limitations. We selected the estimates from models that, to our consideration, included the most important model specifications. We present the results from studies with comparable results in terms of percent change in firearm deaths (when not provided, we calculated the percent change if there was available information for calculations). The estimate in Chapman (115) represents the ratio between pre- and postlaw trends; the estimate in Kapusta (123) represents the difference between pre- and postlaw trends; the estimate in Ozanne-Smith (78) represents the percent change in the rate of firearm deaths; and the estimate in Matzopoulos (126) represents the percent annual change in the rate of firearm homicides in the postlaw period. CAP, child access prevention; CI, confidence interval.

Figure 4.

Summary of results from studies examining the effects of firearm laws (firearms sales, firearms ownership, firearms storage regulations, laws targeting specific firearms and ammunition, and combinations of laws being simultaneously implemented) on suicides and firearm suicides and unintentional deaths. We present only a single estimate from each study because of space limitations. We selected the estimates from models that, to our consideration, included the most important model specifications. We present the results from studies with comparable results in terms of percent change in firearm deaths (when not provided, we calculated the percent change if there was available information for calculations). The estimates from Klieve (120) and Chapman (115) represent the ratio between pre-and postlaw trends; the estimate from Kapusta (127) represents the difference between pre- and postlaw trends; and the estimate from Gagne (112) represents the percent annual change in the rate of firearms in the postlaw period. CAP, child access prevention; CI, confidence interval; UD, unintentional death.