Firearm laws are designed to limit the availability of firearms, often with the aim of reducing or preventing violent crimes. These laws include the introduction of waiting periods or background checks for the purchase of firearms, outright weapons bans, and safe storage laws. In the US, laws may be applied at the local, regional or national level, and may target specific types of crime or be directed at all firearm offences.This narrative summarises the findings of three systematic reviews. It is primarily based on Review 1, a meta-analysis of 29 studies. Review 2 (38 studies) and Review 3 (4 studies) contribute evidence to the mechanism, moderator and implementation sections. All of the primary studies in these systematic reviews use evidence from the USA.
Overall, the evidence suggests that laws to restrict access to firearms have reduced crime.Review 1 aggregated the results from 29 primary studies and found that firearm laws led to a small but statistically significant reduction in gun-related crime. The review found that enhanced prison terms for firearm offences, the introduction of waiting periods between purchase and possession of weapons, and weapon bans all led to statistically significant reductions in crime. Safe storage laws saw a small increase in crime however this was not statistically significant.
Although Review 1 was systematic, many forms of bias that could influence the study conclusions remain. It did not seek out unpublished literature (and therefore did not account for publication bias). The statistical tests conducted were not reported with enough information to determine whether they were appropriate. It also mentioned concerns about the methodological quality of the primary studies it used to calculate the effect size, which may affect the validity of the results.
Reviews 1 and 2 suggested several mechanisms by which firearm laws might reduce gun-related crime. Bans are used to decrease the availability of firearms to potential offenders. Background checks and waiting periods are also designed to decrease firearm availability and restrict those individuals who have criminal histories or are at risk of self-harm from obtaining weapons. As such, these laws aim to reduce the opportunity for offenders to access weapons. Laws that require guns to be unloaded and locked away also decrease availability, particularly to children who may use them in an unsafe manner. These practices are also believed to help reduce the theft of weapons. Review 1 noted, however, that these laws might actually increase crime rates as the likelihood that members of the public are potentially armed may have a deterrent effect on criminals. None of these suggested mechanisms are tested within either review.
The reviews noted a number of potential moderators, particularly when considering the type of law implemented, as outlined in the section on effect. Review 3 looked specifically at the effect of laws prohibiting intimate partner violence perpetrators accessing firearms. Among this group, it found different effects depending on the type of law implemented. Restrictions on the purchasing or possession of firearms for those subject to a domestic violence restraining order (DVRO) was found to be effective at reducing rates of intimate partner homicide (IPH) in two studies. Restrictions on those convicted of a minor domestic violence offence or who had a firearm confiscated at the scene of an incident had no association with rates of IPH.
Review 2 noted that there were difficulties implementing the instant background check system for firearm purchases, primarily due to a lack of records on some restriction categories, or because criminal records are difficult, or sometimes impossible, to retrieve. It was also noted that the laws might be diluted by the fact that many US states have their own provisions requiring longer waiting periods for firearm purchases.
Review 3 found Domestic Violence Restraining Order (DVRO) firearm prohibition laws were not widely implemented, thereby reducing the likely impact of the laws in some areas. To increase the coverage and implementation of DVRO firearm prohibitions, authors suggest that legislative bodies should ensure their statutes cover firearm purchase as well as possession. Legislators should also consider prioritising and systematising the immediate entry of disqualifying DVROs and convictions into relevant background check systems to better enforce purchase restrictions. Procedures to ensure that DVRO firearm possession restrictions are enforced should also be considered.
The reviews did not mention the costs or benefits of firearm laws, and no formal economic analysis was provided.
Overall, the evidence suggests that firearm law have reduced crime. Firearm laws limit the availability of weapons, decreasing the opportunity to use them to commit crime. Different contextual factors were found to impact on the effectiveness of firearm laws including type of law implemented, and type of offence. The implementation of firearm laws may vary by region, and more evidence is needed to understand the conditions in which firearms laws are more or less effective, and the associated economic costs and benefits.
Review 1: Makarios, M. D. and Pratt, T. C. (2012) 'The Effectiveness of Policies and Programs That Attempt to Reduce Firearm Violence: A Meta-Analysis', Crime and Delinquency, 58:2, 222-244Review 2: Hahn, R. A., Bilukha, O., Crosby, A., Fullilove, M. T., Liberman, A., Moscicki, E., Snyder, S., Tuma, F. and Briss, P. A. (2005) 'Firearm Laws and the Reduction of Violence: A Systematic Review', American Journal of Preventative Medicine, 28, 40-71 Review 3: Zeoli, A. M., Malinski, R. & Turchan, B. (2016) 'Risks and Targeted Interventions: Firearms in Intimate Partner Violence', Epidemiologic Reviews, 38, 125-139
This narrative was prepared by UCL Jill Dando Institute and was co-funded by the College of Policing and the Economic and Social Research Council (ESRC). ESRC Grant title: 'University Consortium for Evidence-Based Crime Reduction'. Grant Ref: ES/L007223/1.