Skip to main content

In school rampages, the weapon matters

By Philip J. Cook and Kristin A. Goss
updated 11:22 AM EDT, Fri April 11, 2014
Parents and students embrace near Franklin Regional High School, where authorities say at least 20 people were injured in a stabbing spree Wednesday, April 9, in Murrysville, Pennsylvania. Parents and students embrace near Franklin Regional High School, where authorities say at least 20 people were injured in a stabbing spree Wednesday, April 9, in Murrysville, Pennsylvania.
HIDE CAPTION
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
Stabbings at Pennsylvania high school
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
>
>>
STORY HIGHLIGHTS
  • Authors: Injury, not death, came from school stabbings in Pennsylvania
  • They say research has long found for purposes of life and death, the weapon matters
  • Writers: Deaths from gun attacks higher than those from knives, other weapons
  • If public policy led to reduction in gun use in crimes, murder rate would go down, they say

Editor's note: Philip J. Cook is ITT/Terry Sanford Professor of Public Policy, and Kristin A. Goss is associate professor of public policy at Duke University's Sanford School of Public Policy. They are co-authors of "The Gun Debate: What Everyone Needs to Know," published this month by Oxford University Press. The opinions expressed in this commentary are solely those of the authors.

(CNN) -- It rarely makes sense to draw big conclusions or make public policy on the basis of anecdotes. But the plural of "anecdote" is data, and sometimes one-off events are useful in crystallizing lessons to guide policymakers and inform the public.

So it was with the Pittsburgh-area rampage this week in which a teenager bearing two kitchen knives is accused of injuring 21 high school classmates and a security guard -- but none of them were killed. It's hard to imagine an anecdote that better illustrates what decades of data show: that for purposes of life and death, the weapon matters.

It's called "the instrumentality effect," and we owe the original scholarly findings (more than four decades old at this point) to the eminent University of California criminologist Franklin Zimring. Others, including one of us (Cook), have validated and built upon his insights.

Kristin A. Goss
Kristin A. Goss

The idea that the weapon matters emerges in studies of robberies and assaults. When committed with a gun, these crimes are far more likely to result in the victim's death than are similar violent crimes committed without a gun. For example, the likelihood that a victim will die when robbed by a firearm-wielding attacker is three times as high as when the victim faces an attacker bearing a knife and 10 times as high as when the attacker has another type of weapon. For victims injured in an assault, the likelihood of death is also greater when a gun is involved, especially in cases of domestic violence.

Of course, the choice of weapon could be simply a product of the perpetrator's focus on killing; perhaps it's this intensity, not the choice of weapon, that is really to blame. In light of Wednesday's knife attacks in Pennsylvania, Zimring's findings are particularly telling.

Heroic acts during Pennsylvania stabbing
Newtown mom reflects on anniversary
Community seeks motive for stabbing

To separate the effects of the weapon vs. the intent of the perpetrator, he looked at fatality rates for different calibers of guns. If perpetrator intent were really to blame, zeroing in on attacks with guns would "control" for that effect. Zimring found, as the instrumentality perspective would predict, that people shot by larger caliber guns -- which carry bigger and more destructive bullets -- were more likely to die than those shot by smaller caliber guns.

Adding more evidence to the case that the weapon matters, Zimring and Gordon Hawkins later demonstrated that overall crime rates aren't that much higher in American cities than in comparable cities in other developed countries. We just have higher rates of homicide, and that is because our criminals are more likely to be armed with guns and thus their attacks are more likely to end in the victim's death.

The most important and interesting implication of the instrumentality effect is that if public policy could reduce gun use in crime, the murder rate would go down -- even if the overall crime rate did not. As it turns out, about half of American states have enacted policies that add prison time to felons who use a gun when committing their crimes.

These so-called sentencing enhancements, most of which were adopted in the 1970s and 1980s, were intended to reduce the use of guns in violent acts. Scholarly evaluations based on data, not anecdotes, offer some evidence that these policy innovations have been effective.

This week's tragedy can't help but invoke memories of the mass shooting at Sandy Hook Elementary School some 16 months ago. The difference today is that, because the Murrysville, Pennsylvania, perpetrator chose to use knives, victims' families can look forward to a future with their loved ones -- instead of planning their funerals.

Follow us on Twitter @CNNOpinion.

Join us on Facebook/CNNOpinion.

ADVERTISEMENT
Part of complete coverage on
updated 9:42 PM EST, Fri December 19, 2014
Conservatives know easing the trade embargo with Cuba is good for America. They should just admit it, says Fareed Zakaria.
updated 8:12 PM EST, Fri December 19, 2014
We're a world away from Pakistan in geography, but not in sentiment, writes Donna Brazile.
updated 12:09 PM EST, Fri December 19, 2014
How about a world where we have murderers but no murders? The police still chase down criminals who commit murder, we have trials and justice is handed out...but no one dies.
updated 6:45 PM EST, Thu December 18, 2014
The U.S. must respond to North Korea's alleged hacking of Sony, says Christian Whiton. Failing to do so will only embolden it.
updated 4:34 PM EST, Fri December 19, 2014
President Obama has been flexing his executive muscles lately despite Democrat's losses, writes Gloria Borger
updated 2:51 PM EST, Thu December 18, 2014
Jeff Yang says the film industry's surrender will have lasting implications.
updated 4:13 PM EST, Thu December 18, 2014
Newt Gingrich: No one should underestimate the historic importance of the collapse of American defenses in the Sony Pictures attack.
updated 7:55 AM EST, Wed December 10, 2014
Dean Obeidallah asks how the genuine Stephen Colbert will do, compared to "Stephen Colbert"
updated 12:34 PM EST, Thu December 18, 2014
Some GOP politicians want drug tests for welfare recipients; Eric Liu says bailed-out execs should get equal treatment
updated 8:42 AM EST, Thu December 18, 2014
Louis Perez: Obama introduced a long-absent element of lucidity into U.S. policy on Cuba.
updated 12:40 PM EST, Tue December 16, 2014
The slaughter of more than 130 children by the Pakistani Taliban may prove as pivotal to Pakistan's security policy as the 9/11 attacks were for the U.S., says Peter Bergen.
updated 11:00 AM EST, Wed December 17, 2014
The Internet is an online extension of our own neighborhoods. It's time for us to take their protection just as seriously, says Arun Vishwanath.
updated 4:54 PM EST, Tue December 16, 2014
Gayle Lemmon says we must speak out for the right of children to education -- and peace
updated 5:23 AM EST, Wed December 17, 2014
Russia's economic woes just seem to be getting worse. How will President Vladimir Putin respond? Frida Ghitis gives her take.
updated 1:39 AM EST, Wed December 17, 2014
Australia has generally seen itself as detached from the threat of terrorism. The hostage incident this week may change that, writes Max Barry.
updated 3:20 PM EST, Fri December 12, 2014
Thomas Maier says the trove of letters the Kennedy family has tried to guard from public view gives insight into the Kennedy legacy and the history of era.
updated 9:56 AM EST, Mon December 15, 2014
Will Congress reform the CIA? It's probably best not to expect much from Washington. This is not the 1970s, and the chances for substantive reform are not good.
updated 4:01 PM EST, Mon December 15, 2014
From superstorms to droughts, not a week goes by without a major disruption somewhere in the U.S. But with the right planning, natural disasters don't have to be devastating.
updated 9:53 AM EST, Mon December 15, 2014
Would you rather be sexy or smart? Carol Costello says she hates this dumb question.
updated 5:53 PM EST, Sun December 14, 2014
A story about Pope Francis allegedly saying animals can go to heaven went viral late last week. The problem is that it wasn't true. Heidi Schlumpf looks at the discussion.
updated 10:50 AM EST, Sun December 14, 2014
Democratic leaders should wake up to the reality that the party's path to electoral power runs through the streets, where part of the party's base has been marching for months, says Errol Louis
updated 4:23 PM EST, Sat December 13, 2014
David Gergen: John Brennan deserves a national salute for his efforts to put the report about the CIA in perspective
updated 9:26 AM EST, Fri December 12, 2014
Anwar Sanders says that in some ways, cops and protesters are on the same side
updated 9:39 AM EST, Thu December 11, 2014
A view by Samir Naji, a Yemeni who was accused of serving in Osama bin Laden's security detail and imprisoned for nearly 13 years without charge in Guantanamo Bay
updated 12:38 PM EST, Sun December 14, 2014
S.E. Cupp asks: How much reality do you really want in your escapist TV fare?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT