Natalie Frank, a Ph.D. in clinical psychology, specializes in pediatric psychology and behavioral health.
After a mass shooting like the June 24, 2018 shooting at a North Carolina dance studio leaving one dead and six seriously injured or the February 14, 2018 school shooting in Parkland, Florida which left 17 people dead and 17 more wounded, many wonder if such incidents could have been prevented. They try to determine if there were warning signs that should have been noticed, whether the person had a mental illness, or if the shooter held extreme views on politics or the Middle East.
Even before the final death count had been reported from the shooting spree in Parkland, Florida, politicians, policy makers, mental health professionals, and other experts could be found on the media, voicing their proposals for change. Some talked about gun control, others about mental health screenings, and still more about the need for better security in schools and other public places. Whatever the these individuals made certain assumptions concerning patterns they believed could be found based on profiles created from aggregated data of mass killers. Unfortunately, these assumptions were not always consistent with the facts. These beliefs also failed to recognize that predicting such violence is almost impossible based on common characteristics.
One of the main aspects that has been assumed to be useful in predicting future violence is mental illness. Following the Parkland shooting, President Trump called for a greater focus on mental health problems and care as a means of stopping future mass shootings. However, while it is easy to assume that those who commit such crimes must be mentally ill, the idea that mental health difficulties predispose someone to mass violence is, in large part, a myth. This means mental illness factors cannot be used to predict this type of crime, and increasing screening and treatment, while important in their own rights, will not likely affect future gun violence.
Another problem that make prediction of mass shootings incredibly difficult is the fact that these types of shootings are extremely rare. The vast majority of people in the U.S. and elsewhere will never commit a mass shooting, despite there being a problem in America with gun violence. Even estimating that one in a million people will become mass shooters would be much too high. Given that of the approximately 323 million people in the U.S. almost none will become mass murderers, this makes prediction practically impossible. This is due to the realities of statistics and how they lend themselves to the power of prediction. The rarity of these types of shootings and the fact that most shooters are deceased also means we have limited data to use for prediction.
Probability and Predicting Mass Shootings
Myth: A strong enough prediction model could reliably predict future shootings.
Our inability to determine who could be a mass shooter comes down to statistics and the power of prediction models. This can be best explained through a hypothetical example.
Let’s say that we have a prediction model that is 95 percent accurate. This of course is imaginary as we can’t even predict the weather accurately 95 percent of the time, much less human behavior. However, for the purposes of this example we’ll assume it. This would be considered a great model and one most of us would be willing to trust.
Now let’s say that one in a million people will become a mass shooter. This is also an overestimate since we know the incidence rates of such crimes are far less. So this means that in a sample of one million people, our prediction model will label 95 percent of the harmless people accurately. It should also pick up the one who will become a mass shooter. This seems like good news. What’s the problem.
The problem comes when you realize the prediction model will identify five percent of the harmless people as potential mass shooters along with the one who really is the future murderer. This means in addition to the correctly identified future shooter, the model will also identify 50,000 people who won’t go on to become shooters. We will then simply have narrowed our odds down to knowing that one person in this group of 50,001 people will become a mass murder. This isn’t very useful information.
Other Statistical Reasons That Prevent Prediction of Mass Shooters
Myth: if you use the right statistics you could find what factors predict future shootings reliably.
When conducting research, you need enough data points, in this instances cases of mass shootings, to be able to determine a real effect. In other words, you need a large number of shooters that you have information about to be able to use that information to reliably predict future shootings. When there is too few cases or data points, this means there is low statistical power and you are unlikely to find any meaningful results.
A study with limited statistical power has two problems. First, there is a decreased chance of detecting a real effect when it exists. So if certain factors exist that could reliably predict future shootings, the low number of cases means that you won’t likely determine what these factors actually are.
At the same time, low statistical power means that when you do find statistically significant results, these results are unlikely to reflect a real effect. This means that even if your prediction model has indicated there is a specific factor that predicts future shootings, it is probably this is an inaccurate finding.
Prediction from Warning Signs
Myth: We know enough about warning signs that if we had proper screening techniques we could predict mass shootings.
Most of the attention related to mass shooters has focused on identifying warning signs. The fact is that we do have some information about features that have been found in what is considered to be the typical mass shooter.
For example, 95 percent of mass shooters are male, 67 percent are caucasian and they tend to be older than murderers overall. About 50 percent of mass shooters are over the age of 30, 38 percent are between the ages of 20 and 29 and slightly over 12 percent are under the age of 20.
Common psychological factors that have been determined in these individuals include depression, anxiety, resentment of others, social isolation and withdrawal. They tend to externalize blame or blame others instead of accepting responsibility for their problems. They also often have an interest in violent entertainment and a fascination with weapons, guns in particular.
Yet even knowing all this, it is still almost impossible to determine who might become a multiple shooter before the fact. This is because these characteristics are fairly prevalent in the general population. For example, it has been estimated that about 20 percent of the U.S. adult population suffers from a mental disorder at any time. This amounts to more than 60 million people. We also know that the vast majority of people with mental illnesses are not violent. So although mass shooters share common characteristics most people with those characteristics are not dangerous and do not turn out to be mass murderers. Without risk factors that are specific to mass shooters or even those prone to gun violence or murder, we cannot predict future shootings.
Although there are apparently certain characteristics that are common in mass shooters, this does not mean we can use them to predict the next one. There are two main reasons this is the case. First, prediction models will grossly overestimate who could become a future shooter, providing largely useless information.
The second reason is that the characteristics found in mass shooters are common in the overall population even in combination. However, the vast majority of people with those features are not mass murderers or even violent. Many people may closely resemble the profile for mass shooters. They may be angry, and frustrated about work, school or homelife. They may be withdrawn and reclusive, quick to blame others for their problems and they may even make threatening remarks. However, very few if any of these people will go on to commit murder, much less mass murder.
This also applies to the most commonly referenced factor, mental illness, despite the automatic assumption that anyone who commits such a crime must be mentally ill. While some individuals who become mass shooters appear to have mental health issues, these issues are only identified as problematic after the fact. The fact remains that most people with mental difficulties are not dangerous. While increased and better-funded interventions for mental illness is clearly a great thing, it ultimately won’t have much of a direct effect on mass shootings. Sometimes these shooters have a history of mental illness, or are currently mentally ill, but many individuals who commit mass shootings are not mentally ill in any diagnosable way. Not to mention that the vast majority of those with mental illness do not harm others or become mass murderers as a function of their difficulties.
Although gun control is controversial in the U.S., it is possible that controlling gun access can go hand in hand with mental health treatment to prevent tragedies including mass shootings. Many people with suicidal or homicidal intent are fixated on certain methods of carrying out the impulse. When something blocks their ability to use the method on which they have settled, sometimes that is enough to throw them off balance and delay them in carrying out the deed. This may also make them open to the possibility of getting help which may prevent the action entirely. So while it may not solve the entire problem, limiting access to guns even if there is only a waiting period, may derail an impulse long enough for the person to solve their perceived problem in a different way. If the person decompensates further this may also result in helping them come to attention of someone else who might get them the help they need if they themselves are not in a place to do so.
While this may not address many possible mass shootings in the case of those individuals who meticulously plan their attacks, there is evidence from other countries that limited gun access is related to lower mass shooting rates. One study examining data from 171 countries for the years 1966 through 2012 suggested that rampage shootings were at least partially attributable to differences in firearm accessibility. This study seem to lend support to the possibility that the U.S. and other countries with high rates of gun ownership may be particularly susceptible to future mass shootings. This may be the case even if these countries can be seen as relatively peaceful or mentally healthy based on other national indicators.
When all is said and done, the main questions, I find myself left with after struggling with the fact there seems to be nothing that will consistently eliminate these murderous rampages are these:
Has violence become viewed as something we just have to accept? Or, worse, has it perhaps become a core value of our culture? Is violence now seen as a way of getting what we want or getting revenge we feel we are owed when nothing else seems to work? Most importantly, if the answers to these questions are yes, where does that leave us as individuals and as a nation?
Deadliest Mass Shootings in the U.S. Since 2000
10 killed - May 18, 2018 - Ten children and one teacher are killed and 10 others wounded in Santa Fe Texas, when a 17 year old student opens fire with a shotgun and a revolver. Explosive devices including pipe bombs and pressure cooker devices were found in and around the school placed by the suspect. The shooter was captured unharmed.
17 killed - February 14, 2018 - Seventeen adults and children are killed at a high school in Parkland Florida by Nikolas Cruz a former student. He is charged with 17 counts of premeditated murder.
25 and an unborn child killed - November 5, 2017 - A lone gunman begins shooting at a church in Sutherland Springs. Before it’s over, 25 people are killed. One woman killed was pregnant, bringing the total to 26. Twenty others were wounded. The killer, Devin Patrick Kelley, is found dead though it’s unclear if the gunshot that killed him was self-inflicted.
58 killed - October 1, 2017 - A gunman, later identified as Stephen Paddock, opens fire on a crowd of people attending a concert in Nevada. The gunshots continue for around 15 minutes, according to witnesses. Fifty-eight people are killed and over 500 injured. Paddock is found dead after police believe he shot himself.
49 killed - June 12, 2016 - Forty nine people are killed and 58 wounded in a hate crime inside a gay nightclub in Orlando, Florida. The shooter, Omar Mateen, is shot and killed by police who are attempting to free hostages following a standoff lasting over three hours.
14 killed - December 2, 2015 - Syed Rizwan Farook and Tashfeen Malik, a married couple, kill 14 employees and injures 22 others at a gathering in San Bernardino, California, during a shooting rampage. Both perpetrators are shot and killed by police.
9 killed - October 1, 2015 - Armed with three pistol and a rifle, Christopher Sean Harper-Mercer shoots and kills nine people at Umpqua Community College in Roseburg, Oregon. Nine others are injured. Harper-Mercer is killed during a shootout with police.
9 killed - June 17, 2015 - Dylann Roof, shoots nine people at the historic Emanuel African Methodist Episcopal Church, in Charleston, South Carolina. Eight die at the scene and the ninth dies at a hospital. Roof tells investigators after being arrested the next day he intended to start a race war. Roof is convicted of murder and hate crimes and sentenced to death. If carried out, he would be the first person executed for committing hate crimes.
12 killed - September 16, 2013 - A shooting rampage, carried out by Aaron Alexis, a former navy reservist, occurs at the Washington Navy Yard, in northern Virginia kills 12. Alexis was shot and killed by police.
27 killed - December 14, 2012 - In Newtown, Connecticut, Adam Lanza kills 20 six and seven year old children and six staff and faculty at Newtown Elementary School. Lanza shoots himself and later his mother is also found dead from a gunshot wound.
12 killed - July 20, 2012 - At a screening of the new Batman film in Aurora, Colorado, James E. Holmes sets off two bombs which he follows with a spray of bullets from an AR-15 rifle, a 12-gauge shotgun and two .40-caliber handguns. When it is over, 12 people are dead and 58 are injured. Holmes is convicted on 24 first-degree murder charges, 140 attempted murder charge and a possession or control of an explosive or incendiary device charge. He is sentenced to life in prison without the chance of parole.
8 killed - October 12, 2011 - Eight people are killed during a shooting at the Salon Meritage in Seal Beach, California. Scott Evans Dekraai, shoots and kills eight people at a salon in Seal Beach, California, including his ex-wife. When he is arrested, he is armed with a 9 mm Springfield, a Smith & Wesson .44 Magnum, and a Heckler & Koch .45. Dekraai is convicted and sentenced to eight terms of life in prison without parole, plus an additional 232 year to life term for attempted murder.
8 killed - August 3, 2010 - In Manchester, Connecticut, Omar Thornton is asked to resign after he is caught stealing and selling alcohol. He kills eight co-workers at Hartford Distributors then shoots himself.
13 and an unborn child killed - November 5, 2009 - A U.S. military psychiatrist, Maj. Nidal Malik Hasan opens fire on unarmed soldiers, at a military base at Fort Hood in Texas. He is shot by police and paralyzed from the waist down. Hasan is found guilty of 14 counts of premeditated murder and 31 counts of attempted premeditated murder and is sentenced to death.
8 killed - March 29, 2009 - In a Carthage, North Carolina nursing home, Robert Stewart shoots and kills a nurse and seven elderly patients. He is found guilty of second-degree murder. The district attorney seeks the death penalty but Stewart is sentenced to 141-179 years in jail.
13 killed - April 3, 2009 - After being laid off, Jiverly Wong shoots and kills 13 people and injures four other at an immigrant community center in Binghamton, New York. He then kills himself.
10 killed - March 10, 2009 - Michael McLendon leaves 10 dead in a shooting spree in three different communities in southern Alabama. Those killed include his mother, uncle, two cousins, great aunt, a neighbor and wife of a police officer and their infant daughter. Also killed were a motorist, a woman outside a convenience store and a man who tried to run away and was shot in the back. McLendon was corned at a metals plant and he killed himself when police started shooting. Six others were wounded. When he was killed, McLendon was armed with a handgun, two assault rifles and a shotgun. Police said it looked as if he intended to keep killing people at the plant as his car was filled with more guns and ammunition.
8 killed - December 5, 2007 - In Omaha, Nebraska, 19-year-old Robert Hawkins goes to an area mall, enters the Von Maur department store, shoots and kills eight people and critically wounds four others. He then turned the gun on himself and committed suicide.
32 killed - April 16, 2007 - Another school shooting occurs at Virginia Tech in Blacksburg, Virginia, Seung-Hui Cho, guns down 32 people in two locations and wounding dozens of others on campus. Cho commits suicide before police can apprehend him.
9 killed - March 21, 2005 - At Red Lake High School, in Minnesota, Jeff Weise a sixteen year old, kills his grandfather and his grandfather’s partner at their home. He takes his a Glock pistol and a shotgun and heads for his high school. He shoots and kills five classmates, a teacher and a security guard then kills himself. While many of the kids knew of Weise’s interest in school shootings, there was no motive ever discovered.
Bagalman, E., Caldwell, S. W., Finklea, K. M., & McCallion, G. (2013). Public mass shootings in the United States: Selected implications for federal public health and safety policy. Congressional Research Service.
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Fox, J. A., & Fridel, E. E. (2016). The tenuous connections involving mass shootings, mental illness, and gun laws. Violence and gender, 3(1), 14-19.
Holmes, R. M., & Holmes, S. T. (2001). Mass murder in the United States. Upper Saddle River, NJ: Prentice Hall.
Lankford, A. (2016). Public mass shooters and firearms: a cross-national study of 171 countries. Violence and victims, 31(2), 187.
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© 2018 Natalie Frank
Natalie Frank (author) from Chicago, IL on April 24, 2018:
Will - Thanks for the comment. You make a good point about equating unacceptable violence with unacceptable risk. Along with gang violence, child violence and abuse and other types of violence against youth, we need to first become committed to addressing this type of violence before a real difference can be made. Rare or not all of these things affect lives and cost lives. At the same time when we sensationalize rare events we are taking awareness away from what's important and instead creating fallacies for people to believe. Thanks for stopping by and for the comment.
WillStarr from Phoenix, Arizona on April 12, 2018:
One of the logical fallacies in dealing with such mass shootings is equating unacceptable violence with unacceptable risk. As you point out, mass shooters are extremely rare; therefore the risk is extremely low. In fact, like airliner crashes, mass shootings are big news only because they are rare events. Inner city drug gangs kill an average of 38 teens every week, but because it is so routine, it is not news.
Very well written researched, and presented.
Natalie Frank (author) from Chicago, IL on April 10, 2018:
Thanks for stopping by Linda. It is an important topic and we do need to think about it rationally. Sometimes I think we get caught up in having the right to do something, own something, say something despite the fact it may not ultimately be in our or anyone else's best interest. Gun violence and arguments about what to do about it often feels like that to me.
Natalie Frank (author) from Chicago, IL on April 10, 2018:
You are welcome Dora. It is definitely not an easy problem to solve on any level. My thinking though is anything we can do to prevent even one shooting, though obviously in a perfect world we'd want to stop all of them, is worth the effort. Unfortunately, this is just not a perfect world. Thanks for the comment.
Natalie Frank (author) from Chicago, IL on April 06, 2018:
Yes Billy, we can definitely create safer options for everyone but I think we can do more if we focus on everything we know and accept responsibility for each other. If we know a child is child is bullied we need to do more than just tell them it's a normal part of growing up or to get over it. We need to create work and school environments where harassment isn't an option and if it occurs apply serious consequences to the person and company. We need to have better options for those in abusive situations and heavier penalties for those hurting others. We also need to have serious consequences for those who report these types of occurrences falsely as a means of manipulating or punishing others, such as in the case of swatting. Without the willingness to take a strong line when it comes to all of these situations we will not just continue to have negative events occur such as shootings and other types attacks and aggression but we always be a people in fear who fail to truly connect with others in meaningful ways.
Linda Crampton from British Columbia, Canada on April 06, 2018:
This is an interesting and very informative article. It's also thought provoking. Thank you for sharing all the details, Natalie. Gun violence is an important topic that we need to think about.
Dora Weithers from The Caribbean on April 05, 2018:
Thanks for sharing your insights on this topic. You have given us food for thought, and made us realize that eliminating the problem may not be as easy as we seem to think.
Darla Sue Dollman from Coolidge, Arizona on April 05, 2018:
Is there actually a proven connection between people who use antidepressants (I remember Zoloft was mentioned frequently by the press) and mass shootings? I still have a news article from five years ago that listed all of the mass shootings from recent years and every one of the "shooters" (I hate that word, but can't think of another) was later determined to be on some brand of antidepressants.
Natalie Frank (author) from Chicago, IL on April 05, 2018:
Thank you for your well reasoned response, Flourishanyway. Yes, it is easy to make mental illness a scapegoat for this type of violence as well as other problems we see in society. We have done this for decades and you are right - there is still stigma and bias that goes along with being labeled with a mental disorder. Limiting access to guns or even delaying access can have have a big effect on this type of thing. But this is also much like addressing excessive alcohol consumption with prohibition. There will always be those who shouldn't have guns who none-the-less find a way to get them and at least some of those who really want to carry out a crime involving guns who aren't impulsive will manage to do so. But if gun control prevents even one innocent life lost to me it's worth it. At the same time addressing other issues like mental health and security are important as well. Thanks for stopping by.
Natalie Frank (author) from Chicago, IL on April 05, 2018:
Thanks for the comment, Greenmind. I know the topic is difficult for most people but I am glad to know it came across with some humanity. Thanks for stopping by.
Dr Billy Kidd from Sydney, Australia on April 05, 2018:
We can build a safer environment. That's about it.
Benjamin McQuaid from England, United Kingdom on April 05, 2018:
A very interesting read, Natalie. Predicting mass shootings in the US is similar to predicting terrorism in Europe - hopeless. No model could accurately predict such sporadic events, which is highly unfortunate. Finding a solution to tragedies like these could prove to be very difficult as criminals will always find a way.
Bill Holland from Olympia, WA on April 05, 2018:
Well-researched and dispassionate look at the number one issue in America today.....I really wish I had an answer, but I don't. It's just not as simple as saying eliminate guns from this country....it's just not that simple.
Nikki Khan from London on April 05, 2018:
This is very interesting and informative article Natalie on this very serious issue, Trump Government must take some very strict steps in order to get control over it.
Hundreds innocents have been killed so far in these brutal deeds which could be prevented if precautions were taken before and on time.
But unfortunately I haven’t seen any significant change to prevent this happening again.Hopefully in future may be.
Suzie from Carson City on April 05, 2018:
This is a well-written, educational, common sense presentation of "myths about mass shootings." At the end of the day, it is not something we can easily predict and/or prevent. However sad or maddening this can be, (and to be sure, none of us want to hear this) the best attitude is an honest, clear & concise one. Only then can we hope to arrive at ways to lessen the occurrence of these horrific events & create successful programs to protect and defend human life at all times.
Val Karas from Canada on April 04, 2018:
I am inclined to agree about unpredictability of such shootings. This mostly because shooter's behavior may appear normal in every sense prior to his crime, mainly for two reasons:.
First, because he feels justified for doing it and there is no inner conflict with conscience which would exteriorize itself in an outer animosity which would draw attention to him.
And second, he is keeping his calm "not to spoil the desired effect of a surprise".
As for his motive, it may not even play any significant part at all. Little grudges are a normal part of hormonally stimulated youngsters' interactions---and a potential shooter's twisted mind is likely to blow just about any of those little grudges out of proportion to make it a reason for ultimate violence.
And then, let's face it---any society in which guns availability is close to that of spoons and forks simply has to be ready to pay the price for that (peculiar) pleasure and privilege. Pessimistic as it may sound, there is no way to stop those shootings---period.
A great and thought provoking article, Natalie.
FlourishAnyway from USA on April 04, 2018:
What a superb and rationally presented article. Many people do not understand statistical power, Type I and II errors and their resultant implications. Every one of us knows someone who has a mental illness, whether we realize it or not. With mental illness so prevalent and these types of incidents so rare I get concerned that labeling people with serious mental illness as potential powder kegs/mass violence shooters might prevent them from seeking help. It may also cause them to be ostracized rather than supported by their friends, coworkers, and family.
Mental illness is a convenient scapegoat. We instead need to talk about our gun culture and our easy lax access to guns as a society. Everyone — mentally ill or not — can on occasion lose their self-control. However, when there’s access to firearms, the ability to inflict deadly damage NOW becomes more of a reality. (Just look at suicides as an example.)
GreenMind Guides from USA on April 04, 2018:
What a great article. Thank you for injecting some facts and some humanity into this issue.