Laws related to the sale, use, and carrying of firearms have been associated with differences in firearm homicide rates at the state level. Right-to-carry (RTC) and stand your ground (SYG) laws are associated with increases in firearm homicide; permit-to-purchase (PTP) laws and those prohibiting individuals convicted of violent misdemeanors (VM) have been associated with decreases in firearm homicide. Evidence for the effect of comprehensive background checks (CBC) not tied to PTP is inconclusive. Because firearm homicide tends to concentrate in urban areas, this study was designed to test the effects of firearm laws on homicide in large, urban U.S. counties. We conducted a longitudinal study using an interrupted time series design to evaluate the effect of firearm laws on homicide in large, urban U.S. counties from 1984 to 2015 (N = 136). We used mixed effects Poisson regression models with random intercepts for counties and year fixed effects to account for national trends. Models also included county and state characteristics associated with violence. Homicide was stratified by firearm versus all other methods to test for specificity of the laws' effects. PTP laws were associated with a 14% reduction in firearm homicide in large, urban counties (IRR = 0.86, 95% CI 0.82-0.90). CBC-only, SYG, RTC, and VM laws were all associated with increases in firearm homicide. None of the laws were associated with differences in non-firearm homicide rates. These findings are consistent with prior research at the state level showing PTP laws are associated with decreased firearm homicide. Testing the effects of PTP laws specifically in large, urban counties strengthens available evidence by isolating the effects in the geographic locations in which firearm homicides concentrate.

Background: In 2006, the American College of Surgeons Committee on Trauma mandated implementation of injury prevention programs as a requirement for Level I and II trauma center designation. Little is known about the factors that facilitate or create barriers to establishing evidence-based injury prevention program implementation. The purpose of this research is to generate hypotheses regarding processes used to implement injury prevention programs at trauma centers, identify the factors that facilitate and serve as a barrier to implementation, and develop a model reflecting these factors and relationships. Methods: This is a qualitative study of injury prevention programs at trauma centers. Study participants were chosen from 24 sites representing trauma centers of different patient volumes, geographic regions, and settings in the United States. Subjects participated in phone interviews based on guides developed from pilot interviews with prevention coordinators. Transcribed interviews from eight subjects were analyzed using a system of member checking to code; analysis informed the identification of factors that influence the establishment of evidence-based injury prevention programs. Results: Five themes emerged from the data analysis: external factors, internal organizational factors, program capacity, program selection, and program success. Analysis revealed that successful program implementation was related to supportive leaders and collaborative, interdepartmental relationships. Additional themes indicated that while organizations were motivated primarily by verification requirements (external factor), strong institutional leadership (internal factor) was lacking. Employee readiness (program capacity) was hindered by limited training opportunities, and programs were often chosen (selection) based on implementation ease rather than evidence base or local data. Conclusions: Data analysis reveals five emerging themes of program implementation; using these data, we suggest an initial model of barriers and facilitators for implementing evidence-based injury prevention programs that could serve as the springboard for additional research involving a larger representative sample.

The effectiveness of laws depends on circumstances affecting their enforcement. To assess such circumstances for comprehensive background check (CBC) and straw purchase laws for firearm sales, we examined prosecutions for CBC and straw purchase violations in Pennsylvania and CBC violations in Maryland. We generated pre-post variables and conducted t-tests to assess differences in the mean number of prosecutions filed following changes to the legal environments. The annual number of prosecutions for straw purchase violations increased significantly in Pennsylvania following the passage of a law that strengthened penalties for these violations (difference in means = +1310.86, P=0.003). The annual number of prosecutions for CBC violations decreased significantly in Maryland following a court decision that narrowed the definition of a firearm transfer making enforcement more difficult (difference in means = −20.52, P=0.026). Our findings suggest enforcement is likely influenced by the penalties associated with violating these laws and the interpretation of the language of the laws.

The authors would like to publish this erratum to correct estimates generated from regression analyses due to errors discovered in the coding of some state laws. The following corrections to the laws in Table 1 are warranted: 1) Michigan no longer requires a permit-to-purchase for handgun sales by licensed dealers effective December 18, 2012 (permits are still necessary for private transfers); 2) Connecticut enacted a law prohibiting firearm purchases for violent misdemeanants effective October 1, 1994; and 3) the implementation dates for violent misdemeanant prohi