Facts About Firearm Policy Initiative

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MYTH: Americans Do Not Have More Mass Shootings than other Countries

  • In 2019, researcher John Lott and Carlisle Moody, an economist at the University of William and Mary, attempted to refute University of Alabama criminology professor Adam Lankford’s, finding that 31% of global public mass shootings occured in the U.S.
  • Public mass shootings have a number of definitions. Both Lott and Lankford in this debate use a basic definition of four or more killed in a single incident. They then exclude various categories such as terrorism, gang violence, and battles over sovreignty, but differ on which specific shootings to exclude. For more details of other mass shooting definitions, see GVPedia’s Mass Shootings Report.
  • According to the FBI: “An active shooter is an individual actively engaged in killing or attempting to kill people in a populated area.” An active shooting can have any number of casualties. 
  • Lott and Moody claim that only 2% of global public mass shootings occurred in the U.S. Their conclusion is reached by broadening the definition of mass shooting to include group attacks by armed rebels, militia groups, and terrorists. Attacks by rebels, militias, and terrorists are usually categorized as terror attacks or battles over sovereignty, not mass shootings.
  • Lankford responded by identifying roughly 1,000 foreign cases wrongly included in research by Lott and Moody which skew their results.

Lott’s Claim

In a March 2019 Econ Journal Watch article, John Lott and Carlisle Moody dispute Adam Lankford’s 2016 study which concluded that 31% of global public mass shootings occured in the U.S. despite the U.S. having less than 5% of the global population. 

Using their own database and unique definition of public mass shootings, Lott and Moody claim that 2% of the 2,818 cases of public mass shootings worldwide occurred in the U.S. The authors found that 61 public mass shootings occured in the U.S. between 1998 and 2017, compared to 2,757 incidents in the rest of the world.

Lott made a similar claim on September 18, 2019 when he testified before the Joint Economic Committee of the United States House of Representatives and the Senate. He claimed that the U.S. had 2.16% of mass public shootings from 1998 to 2017, despite having 4.6% of the world’s population. 


Lott and Moody accuse Lankford of misleading readers by “defining and using terms in unconventional ways.” Although Lott claims to have followed the FBI’s definition of mass public shooting, the FBI does not have a definition for mass shootings. The FBI does, however, have a definition for active shooter incidents. The FBI defines an active shooter as an individual actively engaged in killing or attempting to kill people in a populated area.” Lott conflates the  mass shooting definition with the active shooter definition, despite mass shootings and active shootings belonging to two different categories.  

Lott and Moody exclude gang shootings in the U.S. to reduce the U.S. share of mass shootings. To inflate the international share of mass shootings, they include group attacks by uniformed soldiers, paramilitary groups, terrorist organizations, and massacres by large rebel groups. Another example that Lott includes, which is at odds with most definitions of mass public shootings, is an attack on an entire village on the Uganda-Kenya border by 300 Pokot raiders that resulted in many deaths, the burning of 200 houses, and theft of 300 head of cattle. 

“Public mass shooters almost always attack alone,” Lankford writes in a March 2019 response to Lott. “This is common knowledge and has been consistently shown in previous research. Unfortunately, John Lott and Carlisle Moody ignore this fact.” In Lott’s study, 95% of U.S. incidents were committed by a single perpetrator (41 out of 43). In comparison, less than 7% of foreign attacks were committed by a solo attacker.  An average of 22 perpetrators and a median of four perpetrators were involved in the cases in which Lott knew the number of attackers.

Using Lott and Moody’s own data, Lankford found that 29.7% of worldwide public mass shootings by single perpetrators were committed in the U.S. This means the U.S. has 6.6 times more public man shootings committed by a lone gunman than the rest of the world. Lankford notes the 29.7% figure is remarkably close to the 30.8% finding in his original 2016 article Lott attempted to refute.

Lankford concluded the article by highlighting a 2015 op-ed in the NY Daily News in which Lott claimed, “After adjusting for America’s much larger population, we see that many European countries actually have higher rates of death in mass public shootings.” Lankford notes that fact-checker Snopes criticized this research by Lott for using “inappropriate statistical methods” and giving a “false impression.”

Lott’s Counter 

Lott and Moody responded to Lankford in a March 2020 article by criticizing Lankford’s definition of public mass shooting. Lott said that Lankford should not have included cases that occurred in non-public places or involved another crime such as a robbery. To support his claim, Lott cited his own study that Lankford previously refuted. Lott argued that lone-wolf shootings are very common in the U.S. due to  culture and social alienation and not Lankford’s claim of easy access to firearms in the U.S.  


In a March 2020 rebuttal, Lankford explained that his original study focused exclusively on public mass shootings. Lott and Moody include “a small number of public mass shootings and a large number of group attacks by paramilitary fighters, armed rebels, militia group members, and terrorist strike teams.” 

Lankford provided recommendations for readers to sort Lott and Moody’s dataset to more accurately show the U.S.’s disproportionate share of global public mass shootings. Lankford found that Lott and Moody misrepresented roughly 1,000 foreign cases which skewed their results. Lankford concludes with two pages of points in which Lott and Moody made false claims, distortions, or errors, casting doubt on their credibility as researchers.


Adam Lankford, “Public Mass Shooters and Firearms: A Cross-National Study of 171 Countries,” Violence and Victims, 2016
John Lott and Carlisle E. Moody, “Is the United States an Outlier in Public Mass Shootings? A Comment on Adam Lankford,” Econ Journal Watch, March 2019
Adam Lankford, “Confirmation That the United States Has Six Times Its Global Share of Public Mass Shooters, Courtesy of Lott and Moody’s Data,” Econ Journal Watch, March 2019
John Lott, “What type of gun control will actually make us safer?” Testimony before the Joint Economic Committee of the United States House of Representatives and the Senate, Senate website, September 18, 2019
John Lott and Carlisle E. Moody, “Brought Into the Open: How the U.S. Compares to Other Countries in the Rate of Public Mass Shooters,” Econ Journal Watch, March 2020
FBI, “Active Shooter Resources,” FBI Website (accessed January 30, 2020)
Adam Lankford, “The Importance of Analyzing Public Mass Shooters Separately from Other Attackers When Estimating the Prevalence of Their Behavior Worldwide,” Econ Journal Watch, March 2020
John Lott, “Myths of American gun violence,” NY Daily News, June 24, 2015