Outfitter Paul Harris stands behind a shotgun display in the gun library of a new Cabela's store in Anchorage, Alaska, Thursday, March 27, 2014. (photo: Dan Joling/AP)
07 July 15
high-profile shooting, like the June 17 crime that left dead nine
members of a historically black church in Charleston, South Carolina, is
typically followed by calls for greater gun control, along with counter
arguments that the best way to stop gun crimes is with more guns.
"The one thing that would have at least ameliorated
the horrible situation in Charleston would have been that if somebody in
that prayer meeting had a conceal carry or there had been either an
off-duty policeman or an on-duty policeman, somebody with the legal
authority to carry a firearm and could have stopped the shooter,"
presidential candidate Mike Huckabee said in a Fox News interview on
June 19.
A new study, however, throws cold water on the idea that a well-armed populace deters criminals or prevents murders. Instead, higher ownership of guns in a state is linked to more firearm robberies, more firearm assaults and more homicide in general. [5 Milestones in Gun Control History]
"We found no support for the hypothesis that owning
more guns leads to a drop or a reduction in violent crime," said study
researcher Michael Monuteaux, an epidemiologist and professor of
pediatrics at Harvard Medical School. "Instead, we found the opposite."
More guns, more gun crime
Numerous studies have found that gun ownership
correlates with gun homicide, and homicide by gun is the most common
type of homicide in the United States. In 2013, for example, there were
16,121 total homicides in the United States, according to the Centers
for Disease Control and Prevention (CDC), and 11,208 of those were
carried out with a firearm. (Gun suicides
outpace gun homicides by far; in 2013, the CDC recorded 21,175 suicides
by firearm, about half of all suicides that year. Contrary to popular
belief, suicide is typically an impulsive act, psychiatrists say. Ninety percent of people who attempt suicide once will not go on to complete a suicide later, but a suicide attempt using a gun is far more lethal than other methods.)
Monuteaux and his colleagues wanted to test whether
increased gun ownership had any effect on gun homicides, overall
homicides and violent gun crimes. They chose firearm robbery and
assault, because those crimes are likely to be reported and recorded in
the Federal Bureau of Investigation (FBI) Uniform Crime Report.
Along with that FBI data, the researchers gathered gun
ownership rates from surveys in the CDC's Behavioral Risk Factor
Surveillance System, an ongoing, nationally representative survey in
which participants answered questions about gun ownership in 2001, 2002
and 2004. Using those years and controlling for a slate of demographic
factors, from median household income, population density, to age, race
and more, the researchers compared crime rates and gun ownership levels
state by state.
They found no evidence that states with more
households with guns led to timid criminals. In fact, firearm assaults
were 6.8 times more common in states with the most guns versus states
with the least. Firearm robbery increased with every increase in gun
ownership except in the very highest quintile of gun-owning states (the
difference in that cluster was not statistically significant). Firearm
homicide was 2.8 times more common in states with the most guns versus
states with the least. [Private Gun Ownership in the US (Infographic)]
The researchers were able to test whether criminals
were simply trading out other weapons for guns, at least in the case of
homicide. They weren't. Overall homicide rates were just over 2 times
higher in the most gun-owning states, meaning that gun ownership
correlated with higher rates of all homicides, not just homicide with a
gun. The results will be published in a forthcoming issue of the American Journal of Preventive Medicine.
Pinpointing causation
The results do need to be interpreted with caution —
this study method proves that more guns are linked to more gun crime and
overall homicide, but not that access to guns directly causes this
criminal uptick, said study researcher David Hemenway, the director of
the Harvard Injury Control Research Center.
"This study suggests that it's really hard to find
evidence that where there are more guns, there are less crimes, but you
can easily find evidence that where there are a lot more guns, there are
a lot more gun crimes," Hemenway told Live Science.
It's possible that people stockpile guns in response
to higher levels of crime. The researchers tried to tease out whether
this was the case by testing whether gun ownership levels were a
prerequisite for crime or a response to higher crime levels. Though they
still couldn't prove causation, they did find that higher gun ownership
levels preceded crime increases, not the other way around.
"It's difficult to imagine how the hypothesis that
increased ownership reduces criminal behavior could be valid, given our
findings," Monuteaux said.
Other researchers have tried to explore this question
in different ways. Boston University researcher Michael Siegel and
colleagues found in a 2013 study published in the American Journal of Public Health
that over 30 years, gun ownership levels correlated with firearm
homicides, such that the higher the gun ownership rate, the higher the
firearm homicide rate.
However, Siegel said, it was possible that when people noticed the gun homicide rate
going up around them, they went out to purchase guns for protection. To
see if the idea held water, the researchers repeated the study, but
differentiated between the stranger firearm homicide rate and the
nonstranger firearm homicide rate.
They found something striking. Firearm ownership was
not related to the number of stranger firearm homicides — cases where
someone is killed by a stranger.
But when more people owned guns, the nonstranger
firearm homicide rate rose — cases where someone is killed by someone
they know.
"It wouldn't make sense to argue that people only go
out to buy guns if the nonstranger homicide rate goes up, but not if the
stranger homicide rate goes up," Siegel told Live Science. The data, he
said, points to a picture in which confrontations between families,
friends, bosses and acquaintances become lethal in the presence of guns.
"The types of fatalities that occur with nonstrangers
are often situations where the presence of a gun makes all the
difference in the world," Siegel said. "Having guns available makes the
difference between having a fatal confrontation and a nonfatal
confrontation."
Lingering questions
Despite the political firestorm over firearms, some
questions about guns are settled science, Hemenway said. He's made a
side project of surveying active firearm researchers on the literature
in an attempt to learn what areas of research have reached a consensus,
and which remain open.
What's known? One, the presence of a gun in the home
increases the risk of suicide in that home. "That relationship we really
know, no doubt about it," Hemenway said.
Second, the research also confirms that more access to
guns means more firearm homicides, Siegel added. Research on whether
other weapons replace guns when guns are unavailable suggests that they
do not: Overall homicide rates, not only gun homicides, creep up when
guns are in the picture. A 2014 study published in the journal Injury Prevention, for example, found a 0.7 percent increase in overall homicides for every 1 percent increase in household gun ownership. [Fight, Fight, Fight: The History of Human Aggression]
The devil, however, is in the details, which often remain unexamined.
"We know so little about gun training, we know so
little about gun theft, we know some about self-defensive gun use but
not really much," Hemenway said. He and his colleagues are working on
studies about accidental gun deaths in children, about who kills police
and whom police kill, and they'd like to research gun deaths in the
elderly and gun intimidation events, in which a person brandishes a gun
to scare another.
Also unclear are what policies work best to lower the
number of firearms available, Siegel said. He and his colleagues are
tackling that question now.
Another recent study highlighted just how little
researchers know. In July 2013, researchers published a paper in the
open-access journal PLOS ONE,
attempting to mathematically model the trade-off between increased gun
crimes with gun ownership and gun use for self-protection. Because the
available data isn't comprehensive enough, the researchers weren't able
to make specific policy recommendations, study researcher Dominik Wodarz
of the University of California, Irvine, told Live Science.
"What this really does, this model, is it identifies
what parameters are important, which should be measured," Wodarz said.
The hope is to motivate future studies on factors like how many people
own guns legally versus illegally, how likely someone is to die if there
is a shooting, and how many people carry their guns around on a regular
basis.
"The model essentially said that reducing the amount
of guns would be beneficial with the data we have, but this is not
something that we say should inform policy," he said.
How — or if — gun research will inform policy remains
an open question. After federally funded research in the 1980s and 1990s
began to reach a consensus that firearms in the home were linked to
higher chances of violent death in the home, the National Rifle
Association (NRA) lobbied successfully for an end to federal funding of firearms research. The prohibition had a chilling effect on the field. After the elementary school shooting in Newtown, Connecticut, in 2013, President Obama issued an executive order lifting the ban on funding gun research,
but little has changed in the two years since that order, scientists in
the field say. Congress has to earmark the money for such research, and
has not made that cash available to the CDC. The National Institute of
Justice and National Institutes of Health have limited funding for gun
research, but there is very little federal money available, Hemenway
said.
Nor do decision makers necessarily care about
science-based policy: Hemenway recalls presenting his research to a
group of congressional representatives and having one declare that he
didn't care what the data had to say.
"One of the bad things the gun lobby has done is
they've said, 'it's us or them, and you've got to choose sides,'"
Hemenway said. "That makes it so people choose sides, and then they look
for confirmatory data instead of trying to see what the world is really
like."
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