Mass shootings increase local voter turnout but do not shift presidential choices

A study combining data on mass shootings in the U.S. from the Gun Violence Archive with information about voter turnout found that mass shootings mobilize local voters, but do not shift presidential vote choices. This was particularly notable in heavily Democratic areas. The research was published in Science Advances.

Mass shootings are incidents in which multiple people are shot in a single event. They often happen in public spaces such as schools, workplaces, or places of worship. In the United States, their occurrence has increased in frequency since the late 20th century, with notable spikes in the 2000s and 2010s. According to the Gun Violence Archive, since 2014, there have been 400 mass shootings per year on average throughout the U.S.

Compared to overall gun violence, mass shootings are rare. However, they receive intense media attention because of their scale and symbolic impact. Mass shootings generate widespread fear and a sense of unpredictability, affecting not only direct victims but entire communities.

They can lead to long-term psychological consequences such as trauma, anxiety, and reduced feelings of safety among the public. Social trust may erode as people begin to perceive everyday public spaces as potentially dangerous. Mass shootings also intensify political and social polarization, particularly around debates on gun control, mental health, and individual freedoms.

Study authors Kelsey Shoub and Kevin Morris conducted a study in which they tested whether mass shootings increase electoral participation in areas where they occurred. They explain that mass shootings can be expected to increase voter turnout if a narrative is established in the community that ties the mass shooting to government (in)action along with a pathway that links that government (in)action with voting in response.

The study authors collected data on all mass shootings that occurred in the 6 months before or after the 2016 and 2020 elections from the Gun Violence Archive (https://www.gunviolencearchive.org/). A mass shooting was defined as an incident with “a minimum of four victims shot, either injured or killed, not including any shooter who may also have been killed or injured in the incident.” This definition intentionally included gang-related shootings.

They also collected data on voter turnout from the L2 voter file (https://www.l2-data.com/). This database contains information about nearly every registered voter in the U.S., including whether they participated in a given election and the geographic coordinates of their home residence.

From this file, they used data referring to the 2014, 2016, 2018, and 2020 elections. They used data from the VEST Team to identify precincts and assign mass shootings to specific precincts, while information on precinct-level election results for the specific ballot initiative analysis came from the California Statewide Database.

Results showed that voter turnout increased after a mass shooting, but only in the areas geographically closest to where the shooting took place. This was particularly the case in heavily Democratic areas. However, mass shootings do not seem to have shifted presidential vote choices. Authors also report that pre-election mass shootings were associated with increased support for the 2016 California gun reform ballot initiative.

The 2016 Californian gun reform ballot initiative was a state measure approved by voters that required background checks and Department of Justice authorization for ammunition purchases, banned possession of large-capacity ammunition magazines, mandated reporting of lost or stolen firearms, and strengthened enforcement of gun possession laws by certain prohibited individuals.

“We find that mass shootings mobilize local voters (especially in heavily Democratic areas) but do not shift presidential vote choices. Furthermore, we show that pre-election mass shootings were associated with increased support for a 2016 Californian gun reform ballot initiative. Our results show the (geographically bounded) salience of mass shootings for local political engagement and ballot reform efforts,” study authors concluded.

The study sheds light on community reactions to mass shootings in their vicinity. While the authors utilized a regression discontinuity design to make causal claims regarding the increase in voter turnout, they noted that the findings regarding the California ballot initiative specifically should be interpreted as a statistical association rather than a definitive causal link.

The paper, “The effect of mass shootings on voter turnout in the United States,” was authored by Kelsey Shoub and Kevin Morris.