New York's Iron Pipeline Problem

In the wake of COVID-19, researchers and policymakers alike are searching for potential explanations for post-pandemic trends in serious crime. After a notable 25% increase in national homicide rates during the early years of the pandemic, these trends have since begun to decline in many major U.S. cities. In 2023, New York City experienced a 12% decline in murder and had 416 fewer shooting victims relative to the previous year. The most recently observed levels of post-pandemic gun violence are consistent with the city’s impressive crime decline in the wake of the historic crack cocaine era of the early 1990s and show why many view New York City as one of the safest big cities in America.

While these improvements are certainly welcome news, historically disadvantaged communities still disproportionately carry the burden of gun violence. In 2022, Black and Hispanic New Yorkers accounted for 89% of murder victims and 95% of known shooting victims. These patterns also mirror the distribution of arrests involving the recovery of at least one firearm. The observed crime rates might also fail to tell the full story of victimization risk during this period — especially among New Yorkers who may have been overrepresented in the essential labor force. For example, one study by University of Pennsylvania criminologist Aaron Chalfin and Naval Postgraduate School economist Maxim Massenkoff imply that these groups may have experienced greater victimization risk in public spaces early into the pandemic.

Unprecedented disruptions to social life, in addition to the myriad changes in policy, make finding a specific explanation for post-pandemic changes in crime more challenging. However, one notable shift taking place during this period involves an acute increase in U.S. gun sales throughout the country. Survey evidence from Northeastern University epidemiologist Matthew Miller and coauthors suggests that nearly 7.5 million U.S. adults became first-time gun owners from January 2019 to April 2021. While many of these gun sales likely took place among federal firearm licensed dealers who are regulated by federal laws, any subsequent private sales within secondary gun markets largely fall under state-level jurisdiction. With most states possessing few if any regulations on private gun sales, an important question for policymakers involves the extent to which this post-pandemic increase in gun demand is responsible for the observed short-run increases in gun violence — especially among states whose neighbors possess relatively weak gun control policies.

New York State is home to some of the strictest gun laws in the country — second only to California, according to a most recent ranking from Everytown for Gun Safety. While no centralized repository of gun ownership exists, survey evidence from the RAND Corporation suggests that legal gun ownership here is relatively low, with roughly 14.5% of households throughout the state possessing at least one firearm. The fraction of suicides committed with a firearm, a “gold standard” proxy for gun ownership in academic research, also remains remarkably low at 26%, according to 2021 vital statistics data from the U.S. Centers for Disease Control and Prevention. 

This combination of stringent state-level gun laws and low household gun ownership suggests that much of New York’s gun violence problem largely stems from what economists refer to as an externality — with illegal firearms flowing from states with weaker gun laws into states with stricter laws. This policy externality makes it such that states that embrace weaker gun control policies ultimately do not face the full social costs of their policy decisions.

While New York did not necessarily share in the large post-pandemic surge in gun sales witnessed in other parts of the country, this is not true for many of its neighbors who have historically been responsible for much of the illegal gun proliferation to the state. Figure 1 provides some information on trends in potential gun sales as captured by the FBI National Instant Criminal Background Check System. First established under the Brady Handgun Violence Prevention Act of 1993, these federal background checks are required for all firearm transactions made among federally licensed dealers and are often viewed as an informative indicator of potential firearm sales. From 2012-2019, the FBI conducted roughly 1,500 background checks per 100,000 residents for potential gun sales throughout the state of New York. By 2020, this figure increased by 31% relative to the previous year.

States most frequently associated with gun trafficking to New York, commonly referred to as the Iron Pipeline — including Florida, Georgia, North Carolina, Pennsylvania, South Carolina, Virginia and in some cases Ohio — experienced a more pronounced increase in potential gun sales. Over the same pre-pandemic period, Iron Pipeline states were responsible for approximately 3,778 potential gun sales per 100,000 residents before sharply rising to more than 7,000 in 2020. These trends closely mirror those seen in other parts of the country. More importantly, Iron Pipeline states account for an increasing proportion of crime-involved guns recovered throughout New York and successfully traced by law enforcement. In 2014, the Iron Pipeline was responsible for roughly 28% of the crime guns recovered throughout the state of New York. In 2021, these states accounted for 40% of New York State crime gun recoveries. The ATF also reports limited information on what are known as “time-to-crime” rates or the amount of time it took for a crime gun to be recovered when compared to its initial known date of purchase. Shorter time-to-crime rates are often viewed as an indicator of gun trafficking. In 2019, the average time-to-crime rate for successfully traced guns throughout New York was 11.75 years. By 2022, this rate declined to 8.95 years and suggests that relatively newer firearms are being used to commit crimes during this period.

Previous research conducted by Brown University economist Brian Knight, borrowing from a rich literature on international trade, provides some evidence of these gun control policy externalities. Using aggregate 2009 data on successfully traced firearms, the study concludes that firearms generally flow from states with weaker gun laws to states with stricter gun laws. Similar to trade patterns between countries, geographical proximity between states is a strong determinant of gun trafficking relationships. Although information on gun trafficking for cities or regions are quite limited, a 2016 report from the New York State Office of the Attorney General and 2019 report from the Bureau of Alcohol, Tobacco, Firearms and Explosives confirm that these findings also describe New York’s experience as well. 

In New York City, which generally accounts for almost half of all successfully traced crime guns in New York State, nearly 80% of crime guns come from states along Interstate 95. In contrast, roughly half of the crime guns recovered in cities such as Buffalo and Rochester were originally purchased in the state of New York — with the remaining supply coming from nearby Ohio. While neither report can tell us how geographical patterns in local gun trafficking evolved since 2020, they do offer some insights into the most likely sources of illegal gun proliferation in cities throughout the state of New York.

Pinpointing the exact causes of the post-pandemic surge in gun sales remains difficult. The COVID-19 pandemic brought about unprecedented social disruption and population turnover. General social anxiety during this period could also have influenced perceptions of the public safety landscape. Previous studies suggest that anticipated changes in gun control policy, whether they are inspired by national tragedies involving mass shootings or electoral cycles, can have notable effects on the demand for firearms. If the post-pandemic surge in gun demand outside of New York is indeed somewhat responsible for the short-run increases in gun violence inside New York, the policy implications fall along several lines. 

With gun crime throughout New York increasingly involving illegal gun trafficking from other states, one solution involves the continued employment of proven crime reduction strategies by law enforcement. For example, Aaron Chalfin and his coauthors in a recent study find that highly coordinated raids involving suspected gang members, known as “gang takedowns,” reduced gun violence in surrounding New York City public housing by 33% within the first year. Although not explicitly focused on gun homicide, research by myself and coauthors in a separate study shows that increasing the size of the police force can reduce homicide and other serious crime while improving racial disparities in public safety and enforcement activity. While these strategies do not directly address the issue of gun trafficking, they are important evidence-based solutions to reducing gun violence.

Rigorous background checks for private gun sales could also play a vital role in stemming the flow of illegal guns from other states to New York. Iron Pipeline states such as Florida, Georgia and South Carolina currently do not require any form of background check for private gun sales. My own research, based on gun control policy reform in Missouri, also suggests that Black Americans in urban settings may disproportionately bear the consequences of illegal firearm proliferation upon the removal of rigorous local background checks for private sales. Increased gun violence in these communities comes with enormous social costs and can make law enforcement efforts more challenging. Proposed legislation such as the Bipartisan Background Checks Act of 2021 and the Enhanced Background Checks Act of 2021 are designed to addressed some of the well-noted shortcomings of the current U.S. background check system for private gun sales.

Finally, there is still much that we do not know regarding interstate gun trafficking throughout the U.S. Part of this knowledge gap is attributable to federal appropriations riders known as the Tiahrt Amendments. The Tiahrt Amendments severely limit access to ATF gun trace data— restricting data access to government entities such as law enforcement agencies and prosecutors’ offices. The Tiahrt Amendments make it incredibly difficult for researchers, policymakers and other criminal justice stakeholders to rigorously examine patterns in gun trafficking and offer no known public safety value. Despite these restrictions, some government actors have formed unique academic-government partnerships to provide striking evidence on interstate gun trafficking. In two fascinating 2015 papers, Duke University Professor Philip Cook and his coauthors combine Chicago Police Department gun trace data and qualitative interviews to describe the nuanced channels through which individuals with criminal histories access illegal firearms. Through this research, we learned that gang members are quite knowledgeable of state-level differences in gun control policy and employ sophisticated strategies for illegally obtaining these weapons using methods such as straw purchasing. These academic-government research partnerships could play a crucial role in filling the existing knowledge gaps regarding gun trafficking and help further reduce the toll of gun violence.