Focus of the intervention
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
- safe storage laws
In the USA, laws may be applied at the local, regional or national level. They 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 one, which is a meta-analysis of 29 studies. Review two (38 studies) and Review three (four studies) contribute evidence to the mechanism, moderator and implementation sections. All of the primary studies in these systematic reviews use evidence from the USA.
Effect – how effective is it?
Overall, the evidence suggests that laws to restrict access to firearms have reduced crime.
Review one combined 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, weapon bans and the introduction of waiting periods between purchase and possession of weapons all led to statistically significant reductions in crime. Safe storage laws saw a small increase in crime however this was not statistically significant.
How strong is the evidence?
Although Review one was systematic, many forms of bias that could influence the study conclusions remain.
The review did not seek out unpublished literature and therefore did not account for publication bias.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 used to calculate the effect size, which may affect the validity of the results.
Mechanism – how does it work?
Reviews one and two 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.
However, Review one noted 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.
Moderators – in which contexts does it work best?
The reviews noted a number of potential moderators, particularly when considering the type of law implemented, as outlined in the section about effect.
Review three looked specifically at the effect of laws prohibiting perpetrators of intimate partner violence (domestic violence between partners) from 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.
Implementation – what can be said about implementing this initiative?
Review two noted that there were difficulties implementing the instant background check system for firearm purchases. This was 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 three found that 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.
Economic considerations – how much might it cost?
The reviews did not mention the costs or benefits of firearm laws and no formal economic analysis was provided.
- All of the evidence reported here is based on studies from the USA. Caution should be taken when applying these findings to other geographical contexts with different legal frameworks.
- All of the reviews relied on state-level crime rates to analyse the impact of firearm laws. This is a crude form of establishing the relationship between an intervention and its effect. It also masks potential local variation at the county or city level and changes over time. Therefore the results produced by these reviews should be viewed with caution.
Overall, the evidence suggests that firearm laws 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.
More evidence is needed to understand the conditions in which firearms laws are more or less effective, and the associated economic costs and benefits.
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, 222-244
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
Zeoli, A. M., Malinski, R. & Turchan, B. (2016) 'Risks and Targeted Interventions: Firearms in Intimate Partner Violence', Epidemiologic Reviews, 38, 125-139
Summary prepared by
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 reference: ES/L007223/1.