July 24, 2012

2 min read

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Have Lax Concealed-Carry Gun Laws Increased Assaults?

Gun-control laws have changed rapidly in recent years; how they affect crime rates is hotly debated

By Evelyn Lamb & Mark Fischetti

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The tragic shooting at a movie theater in Aurora, Colo., on July 20 has reignited a long-running debate about gun control and laws allowing citizens to carry concealed weapons. Some argue that armed civilians in the movie theater could have mitigated Friday's massacre, whereas others believe that more guns could have led to even more confusion and greater loss of life.

In fact, more guns than ever are in citizens' hands today. Although a lower percentage of the U.S. adult population owns them, those who do own several; the average number of guns per owner is up from 4.1 per person in 1994 to 6.9 in 2004.

Growing roughly in tandem with rising gun ownership is the increase of more lenient regulations allowing people to carry concealed weapons. These laws are up markedly. Concealed-carry laws can be of the "shall issue" or "may issue" variety; in "shall issue" states, law enforcement must issue a permit if certain criteria are met, whereas in "may issue" states, law enforcement has discretion.  Colorado is a "shall issue" state, although some businesses, such as the movie theater where the shooting occurred, prohibit guns on their premises.

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More states are also considering legislation that would permit the carrying of concealed weapons in bars, churches and on college campuses, despite recent tragedies. Both trends are worrisome because they place more hidden guns in more public places. Whether lenient gun-control laws contribute to an increase in gun violence is a hotly contested issue, but research to determine the root of such associations is necessary so that lawmakers can protect citizens' lives as well as their rights.

Graphic by Jen Christiansen

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Evelyn Lamb is a freelance math and science writer based in Salt Lake City, Utah.

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Mark Fischetti was a senior editor at Scientific American for nearly 20 years and covered sustainability issues, including climate, environment, energy, and more. He assigned and edited feature articles and news by journalists and scientists and also wrote in those formats. He was founding managing editor of two spin-off magazines: Scientific American Mind and Scientific American Earth 3.0. His 2001 article “Drowning New Orleans” predicted the widespread disaster that a storm like Hurricane Katrina would impose on the city. Fischetti has written as a freelancer for the New York Times, Sports Illustrated, Smithsonian and many other outlets. He co-authored the book Weaving the Web with Tim Berners-Lee, inventor of the World Wide Web, which tells the real story of how the Web was created. He also co-authored The New Killer Diseases with microbiologist Elinor Levy. Fischetti has a physics degree and has twice served as Attaway Fellow in Civic Culture at Centenary College of Louisiana, which awarded him an honorary doctorate. In 2021 he received the American Geophysical Union’s Robert C. Cowen Award for Sustained Achievement in Science Journalism. He has appeared on NBC’s Meet the Press, CNN, the History Channel, NPR News and many radio stations.

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