Mass Shootings in the United States

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By Sydney Livingston

Published Fall 2023

Special thanks to Robyn Mortensen for editing and research contributions

Summary+

High rates of mass shootings are becoming a uniquely American problem; the US makes up 73% of the world’s mass shootings, yet makes up only 4.25% of the world’s population.^1,2 School shootings, in particular, have increased dramatically in the US since the Columbine High School shooting in 1999, an event many perpetrators have since drawn upon as inspiration.³ There is a strong divide of opinions in the nation regarding how firearm deaths should be reduced, which has complicated and slowed progress in identifying effective solutions.⁴ Each mass shooting causes additional shootings to occur, and each one takes a toll on the mental and emotional health of US citizens both directly and indirectly.^5,6,7 Despite political and social barriers, many organizations are seeing positive outcomes from their efforts to reduce firearm deaths in the US through interventions that include lobbying and violence-prevention programs.⁸

Key Takeaways+

• Mass shootings disproportionately impact people of color, as black students make up only around 16% of the K–12 student population, yet 33% of the victims of school mass shootings.^9,10
• School shootings reached an all-time high in 2022 and have increased by 1,900% from 2010–2022.¹¹
• Mass shootings make up less than 1% of firearm deaths in the US, though the frequency of the events appears more prominent due to widespread media coverage.^12,13,14
• Previous shootings are frequently the catalyst for future mass shootings. About 20–30% of all mass shootings are inspired by previous attacks, and 75% of school shooting perpetrators are known to have a fascination with previous school shootings.^15,16
• While effective gun control measures frequently spark controversy and present challenges in assessing their impact, specific data indicates potential strategies to mitigate firearm-related fatalities, such as the prospect of a 70% reduction in mass shooting deaths if assault weapons were banned.¹⁷

Key Terms+

Assault weapons—Refers to a semi-automatic gun with military features allowing rapid and accurate spray firing.^18,19

Copy-cat phenomenon—Occurs when mass murders are modeled after a previous act because of the detailed and sensational reporting the original act received. Often, the mass murder shares similar characteristics with a previous one.²⁰

Domestic violence—A pattern of abusive behavior towards a household member that includes emotional, physical, sexual, or verbal violence.²¹

High-capacity magazines—Sometimes referred to as large-capacity magazines, high-capacity magazines can hold between 30–100 rounds of ammunition at a time that does not require the shooter to pause to reload.²²

Posttraumatic stress disorder—Also known as PTSD, is a psychiatric disorder that an individual may develop after experiencing a traumatic event or series of events that results in negative symptoms (including sadness, nightmares, or anger) related to the incident even long after it has occurred.²³

Psychotic disorders—A group of serious illnesses affecting the mind’s ability to understand reality, behave appropriately, and make sound judgments. Examples include schizophrenia, delusional disorder, and substance-induced psychotic disorder.²⁴

Red-flag laws—Laws that allow firearms to be restricted from an individual who is at risk for committing any kind of gun violence, even before the individual has committed a crime and could be arrested.²⁵ Red flag laws are also known as “extreme risk protection order” laws, which prevent potentially threatening individuals—either to themselves or others—from having access to firearms.²⁶

Context

Q: What differentiates gun violence from a mass shooting?

A: The US Federal Bureau of Investigation (FBI) defines a mass shooting as an active shooter targeting people in a populated area.²⁷ The US Congress further defines a mass killing as an instance with 3 or more fatalities that do not include the perpetrator.²⁸ Similarly, the Gun Violence Archive adds to this definition by clarifying mass shootings as instances with at least 4 people shot or killed besides the shooter.²⁹ Mass shootings make up only 0.2–1% (between 80 and 400 people) of total firearm deaths in the US each year.^30,31 However, the US has a mass shooting archive that records multiple mass shootings weekly, and some definitions of mass shootings might refer to these as homicides or local gun violence instead because of their frequently lower death toll.³² A broader definition of mass shootings causes more reportings of instances, and different data sources vary in their definition. This brief avoids definitions of mass shootings that skew the public’s perception of their frequency, though slightly varying definitions may be used when relevant. Misconception about the frequency of mass shootings is expected because of varying representation of mass shooting data. However, in reality, public mass shootings are infrequent and make up only a small minority of gun violence instances. The information presented in this brief will address school shootings and other public shootings, and mass shootings will be referred to as instances where 4 or more people are shot. Issues of general gun violence will not be included. Gun violence can refer to domestic violenceA pattern of abusive behavior towards a household member that includes emotional, physical, sexual, or verbal violence., suicides, homicides, or sexual violence by the use of a firearm where fewer than 4 people are harmed. Mass shootings have different causes versus general instances of gun violence, and therefore, this brief will look specifically at the circumstances regarding mass shootings.

Q: What do gun violence and mass shootings look like in the US?

A: Guns are the leading cause of death for children and teens in the US, and firearm deaths among children and teens rose almost 30% from 2019 to 2020—a rate over twice as high as the relative population increase.³³ More than 500 people die every day from instances of gun violence worldwide, 120 of which happen in the US.^34,35 Additionally, the United States makes up 73% of the world’s mass shootings, despite it making up only 4.25% of the world’s population.^36,37 As of May 24, 2023, 234 mass shootings and 22 school shootings occurred in the first half of 2023.³⁸ These numbers were not always commonplace in the US—the first mass shooting that gained significant media coverage in the US was the Columbine school shooting in 1999. Since then, the US has seen a decrease in gun violence in schools, but not in school mass shootings.³⁹ In fact, school shootings reached an all-time high in 2022, and the US saw a 163% increase in school shootings from 2020 to 2022, and a 1,900% increase from 2010 to 2022.⁴⁰ However, a study of California secondary schools showed a 70% decrease in reports of guns brought to school grounds since 2001 as well as an overall decrease in other forms of school violence due to policies and interventions that target these issues.⁴¹ The study only collected data until 2019, so any influx of school violence from COVID-19 was not measured.⁴² There was a 46.3% increase in mass shootings during the COVID-19 pandemic in 2020 (an increase from 417–610 incidents), which peaked at 690 incidents in 2021.⁴³

Q: What role do politics play in the US regarding mass shootings?

A: While mass shootings are widely recognized as tragedies in the US, the suggested solutions to address the issue vary widely and are frequently politically charged. Though individual opinions may have more variance, the 2 major US political parties (Democrats and Republicans) demonstrate a dichotomy of opinions. A California poll showed that the more conservative the voter, the less worried they were about being victims of gun violence, with 78% of the most liberal voters being worried and only 41% of strongly conservative voters being worried.⁴⁴ Consequently, political candidates’ stances on gun policy change depending on the voter. 86% of Democrats said that gun restrictions are more important than protecting 2nd amendment rights versus 12% of Republicans with that opinion.⁴⁵

The dichotomy of opinions in the US has slowed progress on policies that could improve this issue. A deadly elementary school shooting in 2022 was motivation to push more gun control for many Americans. However some Republican policymakers moved to make firearms more accessible than they already had been.⁴⁶ A Tennessee governor proposed that gun restrictions would not deter future perpetrators, and Tennessee lawmakers moved to arm more teachers and allow college students to carry firearms on campus.^47,48 On the same day as the 2023 Covenant School shooting in Nashville, Tennessee, a federal judge signed a state settlement allowing individuals ages 18 and older to carry a handgun without a permit.^49,50,51 In 2023, Kentucky, Ohio, Virginia, Nebraska, and Texas—states that tend to vote more Republican—advocated for limiting gun-free zones, red-flag lawsLaws that allow firearms to be restricted from an individual who is at risk for committing any kind of gun violence, even before the individual has committed a crime and could be arrested. Red flag laws are also known as “extreme risk protection order” laws, which prevent potentially threatening individuals—either to themselves or others—from having access to firearms., and background checks.⁵² As of 2023, there are 25 US states that do not require any permits for carrying a handgun, which is 9 states higher than in 2020. In 2020, a Congressman in Georgia ran for office with yard signs featuring an AR-15 rifle.⁵³ While some areas of the country respond to mass shootings by moving to tighten gun restrictions, others push back firmly on policies perceived as infringing on 2nd amendment rights.

Q: What is distinctive about gun regulation in the United States?

A: Though citizens of the United States make up less than 5% of the world’s population, they make up 46% of the world’s civilian-owned guns.⁵⁴ The US has the largest gun-to-citizens ratio of any country, with 120 guns for every 100 Americans, making it the only country with more guns than people.⁵⁵ The second highest number of civilian guns per capita is the Falkland Islands, though their gun ownership rate is approximately half as high as the United States’.⁵⁶ There are over 78,000 licensed gun dealers in the US, which is more than the populations of 16 US state capitals.^57,58 Knowing the exact number of guns in circulation in the US is helpful in understanding the relationship between the quantity of guns and rates of violence; however, due to illegal exporting, private sales, confiscation, and the fact that firearms can last over a century, it is a challenging number to identify. However, as of 2023, there are approximately 466 million guns in circulation in the US.⁵⁹

The country experienced record-breaking firearm sales during the pandemic, with 64% more sales in 2020 than in 2019.^60,61 In fact, the number of firearms purchased in the US from 2020–2022 is high enough to give each baby born in those years 5 firearms each, and some of them would get 6.^62,63,64,65 In 2020, there were 13.9% more firearm deaths than the previous year, followed by another 7.8% increase in 2021.⁶⁶ The years 2020–2021 introduced 7.5 million first-time gun buyers, and half of this group were female, people of color, and others considered more likely to view the world as dangerous.⁶⁷ Since the pandemic, sales slightly declined, and the year 2023 had an average of 1.4 million firearms sold each month—almost 250,000 more guns sold each month than the year before the pandemic.^68,69 When a mass shooting occurs, gun sales increase in the 30 days following the event and again in December of that same year.⁷⁰ The United States holds the highest rate of homicide by firearms among developed countries, and states with higher levels of household firearm ownership consistently hold higher rates of homicide by firearms and overall homicide.^71,72 The United States is 1 of 3 countries where the right to bear arms is constitutional (along with Mexico and Guatemala). Though it is the only country whose constitution provides zero restrictions on gun ownership (although the Supreme Court ruled that it does not protect assault weaponsRefers to a semi-automatic gun with military features allowing rapid and accurate spray firing.).^73,74 Certain firearms and firearm accessories are not prohibited in the US and are frequently used in mass shootings. For example, high-capacity magazinesSometimes referred to as large-capacity magazines, high-capacity magazines can hold between 30–100 rounds of ammunition at a time that does not require the shooter to pause to reload. hold more than 10–15 rounds of ammunition, allowing a shooter to reduce reload time and minimize victim escape time.⁷⁵ There are only 13 states in the US that have restrictions on purchasing high-capacity magazines.⁷⁶

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There are several laws and restrictions that some states may employ to attempt to reduce gun violence and mass shootings. Extreme risk protection orders allow for the temporary removal of weapons from someone in crisis, and these have been implemented in 19 states and Washington DC.^77,78 Some countries—notably New Zealand and Norway—have instituted widespread change in gun control laws after single incidents of mass shootings. When a deadly shooting in New Zealand resulted in the death of 51 individuals, the parliament almost unanimously voted to ban semi-automatic weapons and assault rifles less than 1 month after the incident.⁷⁹ Australia responded to its mass shooting problem by implementing strong gun regulations and even confiscated 650,000 privately owned guns.⁸⁰ The country has since seen a strong decrease in murders and suicides, suggesting the new legislation was effective. However, because the United States has a uniquely high gun per capita and deep-rooted gun culture, what has been effective in addressing mass shootings in other countries does not necessarily translate to the US.⁸¹

Q: Who are the perpetrators of mass shootings?

A: Most perpetrators of mass shootings are white, 98% of them are male, and they are usually between the ages of 15–25.^82,83,84 School shooters are typically younger and have a median age of 16.⁸⁵ There is a common notion that perpetrators of mass shootings act at random, but this has been proven to be inaccurate. In at least 46% of incidents where 4 or more people were killed, the target was the shooter's current or past intimate partner.⁸⁶ Two-thirds of mass shootings are motivated by domestic violenceA pattern of abusive behavior towards a household member that includes emotional, physical, sexual, or verbal violence. or have perpetrators with a history of domestic violence.⁸⁷ Mass murder is rarely done impulsively, and usually occurs after a loss of a relationship or work and takes place after deliberate (and sometimes extensive) planning.⁸⁸

In the case of the Robb Elementary School shooting that took place in Uvalde, Texas, in 2022, the shooter had alluded to his plans online to friends and had shared videos of beheadings and violent suicides throughout the year prior to the shooting—he even suggested to friends that he would not be around past May of that year, the month the shooting took place.⁸⁹ In the case of the Highland Park parade shooting in 2022, the shooter had been planning the incident for weeks—-which became apparent after authorities viewed the perpetrator’s social media pages after the shooting.⁹⁰

Before the year 2000, mass casualties were mostly perpetrated by older men between their 20s and 40s; in fact, only 2 mass shootings between 1949 and 2017 were committed by a gunman younger than 21.⁹¹ Shooters in their 40’s are primarily perpetrators of workplace shootings, and the youngest groups of shooters act mostly out of influence from previous mass shootings.⁹² In addition to social motivators, researchers have found that young men are more likely than young women to commit mass shootings because they have less control over impulses due to biologically slower male development.⁹³ This slow development is due to discrepancies in impulsive behavior, emotional sensitivity, or other regulating parts of the brains of growing adolescents.^94,95

Perpetrators of school shootings specifically are challenging to identify in advance because there is no one profile of a student who will cause violence. The National Association of School Psychologists says that no such profile exists.⁹⁶ While specific demographics or circumstances may be shared among mass shooters, profiling students as potential shooters could be dangerous because many of them would never commit such an act, and it may overlook students who might.⁹⁷

Although profiling these students is challenging, a few specific trends are consistent among almost all schools and mass shooters. School shooters often previously experienced bullying or social alienation as well as a kind of crisis or trauma in the time leading up to the incident.⁹⁸ Perpetrators often experience some mental or emotional suffering and have access to a firearm. Seventy-two percent of mass shooters are suicidal, though it is essential to understand that not all people who are in a crisis or are suicidal intend to perpetrate a mass shooting.⁹⁹

Q: Who are the victims of mass shootings?

A: The victims of mass shootings have different demographics depending on the perpetrator and their motives. Since the first widely known school shooting at Columbine in 1999, there have been 386 school shootings.¹⁰⁰ Ninety-one percent of the time, the perpetrator targets their current or former school.¹⁰¹ Additionally, black, indigenous, and people of color are disproportionately impacted by mass shootings.¹⁰² Hispanic students are twice as likely to experience campus gun violence, and black students are 3 times as likely—though the perpetrators are still almost always white.¹⁰³ While black students make up only around 16% of the student population, they make up 33% of the victims of school mass shootings.¹⁰⁴ Fatal school shootings usually occur at wealthier, suburban, or rural schools.¹⁰⁵

However, most school shootings occur at poorer, urban, high-minority schools, and non-students often perpetrate these and are usually motivated by disputes. Most US mass shootings happen in the South and West, though mass shootings in the West primarily occur in California.¹⁰⁶ Two-thirds of mass shootings are domestic violence (DV) related or perpetrated by a shooter with a DV history, which means that many victims of mass shootings are victims of DV.¹⁰⁷ Additionally, domestic violence-related shootings have a higher fatality rate than unrelated shootings. Only 1 in 6 people survive a domestic violenceA pattern of abusive behavior towards a household member that includes emotional, physical, sexual, or verbal violence. (DV) related shooting rather than 1 in 3 people surviving a non-domestic violence related shooting.¹⁰⁸ Other civilians are killed in targeted mass shootings, which is why the death toll is higher than a single person with whom the shooter may have been involved.

Contributing Factors

Firearm Access

Access to firearms increases the amount of mass shootings because mass shootings can only occur when the perpetrator has access to a firearm. The complexity of mass shootings resides in the reasons for why and how potential threats obtain these weapons. For example, over 80% of guns used in school shootings were taken from family members.¹⁰⁹ A sophomore at Oxford High School in Michigan killed 4 students in a 2021 shooting with a firearm that his father had purchased 4 days prior to the event.^110,111 Easy at-home access to guns is a common trend among perpetrators of school shootings specifically.¹¹² Many school shootings happened where the gun at home was not safely stowed and protected. There are a few instances where the weapon had been protected, though the shooter typically still had easy access to it in those cases.¹¹³

Seventy-seven percent of mass shooters used weapons that were acquired legally, only 13% of mass shooters purchased illegal weapons, and the remaining 10% are unknown.¹¹⁴ All states in the US require licensed firearm dealers to perform background checks on buyers, though some states do not require private sellers to conduct background checks.^115,116 The deadliest mass shooting in the United States to date, the Las Vegas 2017 music festival shooting, was perpetrated by someone using legally purchased firearms.¹¹⁷ The shooter even passed a background check at the gun shop where the weapons were purchased and avoided raising any red flags to the owners of the store.¹¹⁸ A shooting at a supermarket in Buffalo, New York, in 2022 resulted in the loss of 10 lives and was committed by a perpetrator who had also legally purchased the firearms used in the attack.^119,120 The 18-year-old suspect had recently caused an episode at school because of violent threats to classmates. While this forced the suspect to undergo psychological evaluation, the state's red flag laws were not enacted and did not impact the suspect’s access to firearms.¹²¹ Firearm access is often achievable for perpetrators, which has caused debate on the impacts of background checks, semi-automatic weapon purchases, and red-flag lawsLaws that allow firearms to be restricted from an individual who is at risk for committing any kind of gun violence, even before the individual has committed a crime and could be arrested. Red flag laws are also known as “extreme risk protection order” laws, which prevent potentially threatening individuals—either to themselves or others—from having access to firearms. in the United States.

Firearm access varies throughout the US due to an assortment of gun restrictions. While one state might have strict gun laws, its neighboring state could have very few.¹²² Because of this, gun trafficking—placing firearms into illegal markets—often happens when a gun is purchased in a state with relaxed gun laws and then resold in one with strict gun laws.¹²³ Additionally, states with stricter gun laws see fewer mass shootings. Hawaii, a state with strict gun laws, has some of the lowest rates of gun violence, whereas Florida, a state with relaxed gun laws, has experienced 15 mass shootings in the first half of 2023 alone.^124,125 While the average US citizen will not commit a mass shooting simply because they have access to a gun, a person who intends to commit mass violence has a greater capacity to do so with easy access to a firearm.

News Coverage of Previous Shootings

Previous instances of violence are frequently used as models for perpetrators of mass shootings. About 20–30% percent of all mass shootings are inspired by previous attacks, and 75% of school shooting perpetrators have been shown to have a fascination with previous school shootings.^126,127 The 1999 Columbine school shooting resulted in the death of 12 students and 1 teacher.¹²⁸ While this shooting is commonly considered the first of its kind, this perception arises primarily due to its exceptional notoriety and extensive media coverage.¹²⁹ For those very reasons, Columbine has been a source of fascination and even inspiration to others looking to recreate a similar kind of incident. The perpetrator of the Sandy Hook Elementary School shooting created a blog as an homage to the Columbine shooting, and a North Carolina shooter vacationed to Columbine with his mother and fantasized about killing any survivors.¹³⁰ While these might seem like extreme examples, investigations on perpetrators have shown that nearly half of school shooters since 1999 have used Columbine as their model.¹³¹ Subsequent perpetrators of school shootings since Columbine have even donned trench coats while committing the act, modeled after the Columbine perpetrators’ attire. Instigators of mass shootings consistently identify an instance of violence where a previous perpetrator had similar motives or life experiences as they did and model their own act after them.^132,133

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Interestingly, the Columbine shooters themselves were influenced by the high media coverage that the 1995 Oklahoma City bomber received.¹³⁴ While their act was not modeled after a mass shooting, this example demonstrates the “copy-cat phenomenonOccurs when mass murders are modeled after a previous act because of the detailed and sensational reporting the original act received. Often, the mass murder shares similar characteristics with a previous one.” or generalized imitation.¹³⁵ The perpetrator of an Orlando nightclub shooting admitted to being inspired by the Boston Marathon bombing in 2013, an attack that received so much media coverage that one of its perpetrators is estimated to have received over $10 million in free publicity—more than almost any other American celebrity received at the time.^136,137 In another instance, the Parkland, Florida school shooting in 2018 resulted in US media outlets running more than 7,900 online stories about the shooting in the 2 weeks following the event.¹³⁸ For perpetrators seeking notoriety due to mass violence, these high levels of media portrayals of previous attacks have historically been incredibly motivating.

There is a kind of “contagion” that occurs with mass shootings that lasts approximately 14 days after an incident.¹³⁹ This means that when one mass shooting occurs, it will be soon followed by more. The difference between a " contagious " shooting and one that is not is often the amount of media coverage they receive.¹⁴⁰ Any media coverage providing details about a shooter or the incident makes the shooting a replicable model for future perpetrators.¹⁴¹ In the case of a significant shooting like Columbine, future perpetrators may draw on those instances as models for more than 14 days post-incident. A devastating mass shooting in El Paso, Texas in 2019 that resulted in the death of 23 individuals and 23 others injured was inspired by the shooting in Christchurch, New Zealand, almost 5 months before.¹⁴² Prior to the shooting, the El Paso shooter had posted an online manifesto describing the hope to emulate the Christchurch incident.^143,144 The Christchurch shootings were terrorist attacks, and similarly, the El Paso shooting has been defined as an act of domestic terrorism.^145,146

Media coverage on mass shootings has shifted since Columbine, and more recent incidents feature less coverage of personal details about the perpetrators. In the 1970s, a panic started about the rise of serial killers and related violence. The number of active serial killers peaked at almost 300 in the 70s, and the 250 active serial killers in the 80s accounted for 120–180 deaths yearly.¹⁴⁷ The serial killer panic of the 70s and 80s diminished significantly in recent years, but it is not clear whether the media coverage or serial killer occurrences diminished first (though criminal-tracking technology has also greatly improved since then).^148,149 Though it is difficult to measure how much responsibility the media itself holds for the rise and fall of violence phenomena, since the Columbine shooting, the panic has shifted to the newer generation’s terror of mass shootings, correlated with increased media coverage of these events.

Poor Mental and Emotional State

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In order to understand why mass shootings occur, it is critical to understand the perpetrators’ condition before the incident. Consistently, researchers find it more helpful to look at mass shootings as a form of violent suicide because the perpetrators commit this act with no intention of coming out alive.¹⁵⁰ In instances of mass shootings, perpetrators commonly experience these suicidal feelings as a result of some form of early childhood trauma (45% of all mass shooters experienced this).^151,152 Examples include severe bullying, abuse, or assault. In school shootings, particularly, bullying is a common motivator for the perpetrator who then uses the school setting to end their own lives and the lives of others.

Almost all mass shooters experience a crisis in the time leading up to the incident.¹⁵³ Some negative personal experiences cause the shooter to become angry, and a person or group of people become a target due to their rage. For school shootings, the anger may be a result of bullying; for a workplace shooting, their grievance may develop from the recent loss of a job.^154,155 These dangerous mindsets are not hidden from the world—almost all mass shooters display warning signs. In the case of school shooters, all perpetrators exhibited alarming behaviors, and most of them even discussed their violent plans with someone else before the event.¹⁵⁶ However, there is a lack of standardized protocol for when a person displays warning signs, though schools and local communities may establish their protocol for threat assessment and protocol.¹⁵⁷ An English teacher was approached by a student who showed her cut marks on his arms, but she did not know how to approach the student and ultimately passed the situation along to another faculty member.¹⁵⁸ That student was the mass shooter at his school 2 years later, and the teacher expressed regret that there had not been a better protocol for her to follow when a student approached her with such an alarming concern.

If someone recognizes someone at risk for committing violence and has displayed warning signs, this should be reported immediately to local authorities.¹⁵⁹ Mental health professionals, counselors, or community leaders are vital resources if someone appears to be struggling but not at risk for committing violence.

While challenging life circumstances may cause mental or emotional problems for mass shooting suspects, it is incorrect to assume that all mass shooters have a severe mental illness. This notion comes from a common attribution of bad behavior with mental illness, which are not the same thing and are potentially harmful to confuse with one another.¹⁶⁰ Mass shooters with severe mental illness make up only 5% of incidents.¹⁶¹ Mass murderers with psychotic illnessesA group of serious illnesses affecting the mind’s ability to understand reality, behave appropriately, and make sound judgments. Examples include schizophrenia, delusional disorder, and substance-induced psychotic disorder. are less likely to use firearms and more likely to use other forms of violence.¹⁶² Much higher are rates of non-psychotic psychiatric illness among mass shooters, including depression and anxiety, though only around 25% of shooters experience these (closely matching rates of the general population), and it is incidental in most cases.^163,164 However, early childhood trauma is much more common among mass shooters, and researchers have found that when a trauma experienced earlier in life goes unaddressed, it can cause anger later in life that may fuel these incidents.¹⁶⁵ When some kind of history of trauma is paired with a more recent crisis (including suicidality), a violent incident is more likely to follow if the perpetrator adopts radical views from online engagement.¹⁶⁶ While they may not always become radicalized specifically by others who have committed mass shootings, they might be in online groups that advocate for violence directed at particular groups, such as minorities. For example, the perpetrator of a mass shooting in Buffalo, New York in 2022 that resulted in the death of 10 black people had been a member of several online platforms that promoted racism and violence, and he then live-streamed the attack on Twitch (a US live-streaming service).^167,168,169 When radicalization and mental or emotional struggles are paired with access to a firearm, the results have contributed to many attacks the United States has faced.

Consequences

Community Challenges

When a mass shooting happens, the targeted community continues to suffer long after the event has passed. A mass shooting can become part of a community’s identity, exacerbating the association between that area and the tragedy.¹⁷⁰ A community can come together or begin to fall apart in the aftermath of a mass shooting.¹⁷¹ For example, Uvalde, Texas, tried to heal after the mass shooting at Robb Elementary School in 2022, where 21 people were killed.¹⁷² Many people in Uvalde who were directly affected by this shooting continue to try and find closure since the event.¹⁷³ However, there is disagreement about how accountability should be taken, whether everyone should try to remember or move on from the event, and what change should be expected from the police department and school system.¹⁷⁴ Ultimately, this climate led to high disdain and animosity for the victims’ families in Uvalde while others struggled to move on. In another example, two students at Marjory Stoneman Douglas High School committed suicide within days of the 1 year anniversary of the shooting that occurred there, causing further grief and turmoil to torment the existing community.¹⁷⁵ Alternatively, in Newtown, family members continue to grieve the loss of life at the Sandy Hook elementary school shooting over 10 years later and describe how the trauma of that day still feels new.¹⁷⁶ While 1 mass shooting may have occurred with only a few people present, the resulting trauma affects an entire community for years after the incident.¹⁷⁷

Social tension from mass shootings is not limited to a community scale. Throughout the nation, there is disagreement about the source of mass shootings and how they should be prevented.¹⁷⁸ Families of mass shooting victims have gathered to rally for Congress to outlaw assault rifles. While unity is found among gun violence survivors and victims’ families, they face an uphill battle to create change.¹⁷⁹ Certain groups in the US disagree about how significant the issue is, with 82% of black Americans feeling that gun violence is a very big problem, 58% of Hispanic adults, and only 39% of white adults.¹⁸⁰ Around half of American adults feel that stricter gun laws would reduce mass shootings, while the rest feel that those laws would make no difference (42%) or even increase mass shootings (9%).¹⁸¹ There are frequent debates about the ethics of the National Rifle Association (NRA), its funding, and what firearms should be outlawed.^182,183 New York Attorney General Letitia James filed a lawsuit against the NRA in 2020 for mismanaging charitable funds—more than $64 million in 3 years—violating state and federal laws and even the NRA’s bylaws and policies.¹⁸⁴ The NRA has protested many accusations in recent years, but 2019 polls show that Democrat support for the NRA has lowered by 9%, independent support is 6% lower, and Republican support has remained virtually unchanged.^185,186 As a whole, 48% of Americans support the NRA, making this the second period in 30 years where support has dropped below 50%.¹⁸⁷

Economic Impact

Short-term Economic Challenges

A community's financial burdens from a mass shooting can be severe. Gun violence costs add up to $557 billion each year, including long-term medical care, criminal justice system resources, lost wages, and more.¹⁸⁸ Firearm injuries are costly to treat, with medical bills costing more than twice as much as other inpatient and emergency hospital visits.¹⁸⁹ As a response to gun violence, schools implement safety measures that cost $3 billion each year.^190,191 Communities that have experienced mass shootings also experience decreased business growth (by around 4%) as well as decreases in the growth of prices of homes.¹⁹² However, gun manufacturers often see an increase in stock price in the period following a mass shooting. Firearm manufacturer Smith & Wesson saw a 12% stock price increase in the 30 days following the Uvalde, Texas elementary school shooting.¹⁹³ However, US employees lose $147.32 million daily due to missed work due to injury or death from firearms.¹⁹⁴ Communities with growing income inequality are also more likely to experience mass shootings than others, which then further exacerbate economic challenges.¹⁹⁵ The average amount each citizen of the US spends on gun violence each year is $1,698—though the cost is half that in states with stricter gun laws and twice as much in states with weaker gun laws.¹⁹⁶

Long-Term Economic Challenges

Mass shootings that specifically affect children can lead to serious economic repercussions in their future. Economic struggles often arise in a child’s future due to challenges that develop in the time following a mass shooting. For example, children affected by a mass shooting have higher levels of disengagement at school, lower graduation rates, challenges with reading and math, and even health disparities later in life.¹⁹⁷ In 2002, there were a series of shootings in Washington DC, known as the DC sniper attacks, and elementary schools in the area experienced a 2–5% decrease in proficiency (measured by students’ achievement of required academic benchmarks).^198,199,200 Challenges with educational attainment for children decrease their economic prospects, making the economic impact of mass shootings long-lasting. A study on schools in Texas that experienced mass shootings found a 12% increase in overall absence rates and a 28% increase in chronic absenteeism, which describes a student who is absent 10% or more of the time.^201,202 The on-time graduation rate for chronically absent students is 16% lower than their peers.^203,204,205 A child who survives a school shooting in grades 10–11 is 10% less likely to attend college and 15% less likely to receive a bachelor’s degree by age 26.²⁰⁶ Black and lower-income students experience these repercussions more than their non-black and wealthier peers.²⁰⁷ A supermarket shooting in Buffalo, New York left its community struggling financially. When a mass shooting soon followed in Uvalde, Texas, many Buffalo citizens felt that the loss of national attention would once more leave the east side on their own to gain economic stability.²⁰⁸ Storeowners, grieving family members, and survivors struggled to recover financially and emotionally from the trauma a mass shooting leaves behind.

Impact on Mental Health

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A mass shooting can have a widespread impact on the trust its citizens have in their everyday safety, causing mental health concerns even among citizens who were not directly impacted by the incident. The disruption of the public’s feeling of safety is primarily due to the unpredictability of a mass shooting.²⁰⁹ The repercussions of mass shootings on young people are especially conspicuous, to the point that many of them consistently identify escape routes in public areas in case a mass shooting occurs.²¹⁰ Emma Riddle, a survivor of a school shooting, wore tennis shoes every day for 4 months after the event in case she would be forced to run away from an active shooter again.²¹¹ There was a 57% increase in suicides between 2007 and 2018, and given the rise in both suicides and mass shootings, it is possible that a correlation exists between these phenomena.²¹² The distress accompanying mass shootings is not exclusive to young Americans—one-third of US adults report avoiding certain public spaces because of their fear of mass shootings.²¹³

High media coverage of mass violence also correlates with acute stress and posttraumatic stress.²¹⁴ Additionally, more worry about future violence predicts higher levels of media consumption, which then fuels more trauma and stress symptoms and creates a damaging cycle.²¹⁵ Seventy-five percent of Americans aged 15–21 say that mass shootings are a significant source of stress for them and most adults.²¹⁶

A phenomenon sometimes referred to as “mean world syndrome” can sometimes develop when high levels of media are consumed, leaving individuals feeling that the world is more violent than it truly is.²¹⁷ Those with personal trauma histories are more prone to these symptoms when a traumatic mass violence act occurs.²¹⁸ However, the reactions to frequent mass violence vary greatly depending on a person’s factors, such as trauma history and proximity to a mass shooting incident.²¹⁹ While one person may experience an increase in fear, another may feel numb to the violent experiences.^220,221 The numbing that can occur with mass violence is common due to the high levels of fatalities that sometimes occur.²²² An example is when the Parkland, Florida school shooting resulted in the loss of 17 lives, the resulting terror did not increase 17 times in an instant versus where only 1 child was murdered.

Mental health challenges resulting from mass shootings have impacted US citizens regardless of their proximity to a mass shooting incident. However, those who are closest to them can develop specific and intense mental health challenges.²²³ Psychiatric disorders increased by 200% for a gun violence survivor in the month following the incident, and child survivors of gun violence experienced a 21% increase in the use of antidepressants in the 2 years following the incident.²²⁴ The mental and emotional health challenges that develop after a mass shooting are posttraumatic stress disorderAlso known as PTSD, is a psychiatric disorder that an individual may develop after experiencing a traumatic event or series of events that results in negative symptoms (including sadness, nightmares, or anger) related to the incident even long after it has occurred. (PTSD), self-harm, substance abuse, and major depressive disorders. Most of these will diminish over time for survivors of mass shootings, but some (including PTSD) are long-lasting.²²⁵ Younger children may experience symptoms like headaches and stomach aches and can engage in “traumatic play” where they reenact the incident (sometimes indicating PTSD).²²⁶ Children who live closest to a shooting (2–3 blocks) were more likely to have an emergency room visit for mental health-related reasons in the 2 months following the incident.²²⁷ Reasons for the visit could include self-harm, suicide ideation, or panic attacks. Mental health concerns can directly result from mass shootings for those directly involved with the incident and anyone who fears a similar event happening in their own life.

Practices

Reducing Firearm Death

Mass shootings are unique from other forms of gun violence and make up a small minority of firearm deaths. Because of this, potential solutions for mass shootings should not be understood as equally effective for different forms of gun violence. There are many laws and policies that organizations advocate for in an effort to reduce mass shootings. It is important to note that some of these policies may be specifically helpful for mass shootings rather than general instances of gun violence, including murders or suicides.²²⁸ Many US-based organizations effectively lobby for policies directed at reducing mass shootings, including Everytown for Gun Safety, Brady, Sandy Hook Promise, and Moms Demand Action.^{229,230,231,232} Some organizations advocate for increased gun control in the US, especially concerning high-capacity magazinesSometimes referred to as large-capacity magazines, high-capacity magazines can hold between 30–100 rounds of ammunition at a time that does not require the shooter to pause to reload.. These guns allow a mass shooter to fire more rounds without the pause to reload ammunition that would have otherwise allowed victims to defend themselves or find safety.²³³ Data shows that states that ban high-capacity magazine purchases have fewer casualties in mass shootings and fewer instances of mass shootings overall.²³⁴ Because the primary age for offenders is 18–21, restrictions that prevent younger people from having easy access to firearms would also likely produce a decrease in mass shootings.²³⁵

Impact and Gaps

While some laws and policies that promote gun control might intuitively seem to reduce mass shootings, some regulations have little data supporting their effectiveness. For example, little data suggesting that background checks are effective at targeting perpetrators of mass shooters (though this likely does not apply to other forms of gun violence).²³⁶ Other policies advocated for include more police in schools or drills for students to prepare for an incident. Additionally, some feel that more lax concealed carry laws would give civilians a better opportunity to defend themselves in mass shootings. However, no data supports any of these laws effectively reducing deaths from mass shootings.²³⁷

Many simple safety procedures may be effective practices in reducing firearm death; for example, a shooting at a Jewish School in Memphis in 2023 seems to have been averted when the gunman could not get past the double security doors that were in place at the school.²³⁸ The lack of data for some gun safety measures does not necessarily mean they are ineffective but are not implemented widely enough for substantive data. There are essential leads on what could decrease firearm deaths in the US, but research and data are minimal. While firearm deaths are around the same as Sepsis (a life-threatening response from infection), funding for research on firearm deaths is only 0.7% of that of Sepsis.²³⁹ Despite limited data, there was a federal ban on assault weaponsRefers to a semi-automatic gun with military features allowing rapid and accurate spray firing. between 1994–2004 associated with an anticipated 70% decrease in mass shooting deaths if enforced today.²⁴⁰ Shootings from 2015–2022 that involved an assault weapon resulted in twice as many deaths in those incidents, further demonstrating that the ban would have been effective had it persisted after 2004.²⁴¹

One organization that lobbies for effective gun control measures is Sandy Hook Promise. This organization effectively rallies people and resources to promote policies and programs that decrease firearm deaths in the US. Sandy Hook Promise has a program called Say Something that educates students on assessing potential gun violence threats. In 2022, one student who was trained in the program saw another student on the bus with a gun in their backpack and reported it to the bus driver.²⁴² Authorities retrieved the gun paraphernalia from the potential threat who confirmed their intention to kill someone at school that day. Over 18 million people and 23,000 schools in the US have undergone at least one of Sandy Hook Promise’s Know The Signs programs that are provided at no cost to schools. Sandy Hook Promise’s National Crisis Center has received 130,000 tips since their anonymous reporting system’s launch in 2018 that have averted at least 9 credible school shooting threats and hundreds of teen suicides.²⁴³ Sandy Hook Promise has established programs that successfully target mental health, depression, suicide, and bullying, critical risk factors for gun violence. While passing gun control laws can be a lengthy political battle, many organizations promoting gun safety in the US are working effectively to establish programs and policies that reduce firearm deaths.

Preferred Citation: Livingston, Sydney. “Mass Shootings in the United States.” Ballard Brief. October 2023. www.ballardbrief.byu.edu.

Viewpoints published by Ballard Brief are not necessarily endorsed by BYU or The Church of Jesus Christ of Latter-day Saints