Research in context
Evidence before this study
We searched PubMed with the terms “gun” OR “firearm”, AND “policy” OR “law” OR “legislation” OR “legislature” OR “laws” OR “policies”, for articles published in any language before May 1, 2015. We identified 1154 articles, of which 1008 remained after adding the restriction term “humans”. Several articles assessed the effect of one or few firearm laws or policies, but we identified only six articles that studied the effect of several laws on firearm deaths in the USA, and only two that deemed all firearm laws as a score.
Added value of this study
Our findings showed that of the laws we surveyed, only a few were associated with reduced firearm mortality, whereas most were either associated with increased mortality or had no conclusive association. We showed that federal-level implementation of the three most strongly associated laws—universal background checks for firearm purchase, background checks for ammunition, and requiring firearm identification by either microstamping or ballistic fingerprinting—would substantially reduce overall national firearm mortality.
Implications of all the available evidence
Implementation of background checks for firearm or ammunition purchase and firearm identification nationally could substantially reduce firearm mortality in the USA. However, very few of the existing state-specific firearm laws are associated with reduced firearm mortality, and this evidence underscores the importance of focusing on relevant and effective firearms legislation.