Concealed Carry in The United States - Research On The Efficacy of Concealed Carry

Research On The Efficacy of Concealed Carry

See also: List of defensive gun use incidents

In Florida, which in 1987 introduced the "shall-issue" concealed carry law used as a model for other states, one study found that crimes committed against residents dropped markedly upon the general issuance of concealed-carry licenses. However, another study suggests that in most states with shall-issue laws, there were increases in crime of all types.

In a 1998 book, More Guns, Less Crime, economics researcher John Lott's analysis of crime report data claims a statistically significant effect of concealed carry laws on crime, with more permissive concealed carry laws correlated with a decrease in overall crime. Lott studied FBI crime statistics from 1977 to 1993 and found that the passage of concealed carry laws resulted in a murder rate decrease of 8.5%, rape rate decrease of 5%, and aggravated assault reduction of 7%.

In a 2003 article, Yale Law professors John J. Donohue III and Ian Ayres have claimed that Lott's conclusions were largely the result of a limited data set and that re-running Lott's tests with more complete data (and nesting the separate Lott and Mustard level and trend econometric models to create a hybrid model simultaneously calculating level and trend) yielded none of the results Lott claimed. However Lott has recently updated his findings with further evidence. According to the FBI, during the first year of the Obama administration the national murder rate declined by 7.4% along with other categories of crime which fell by significant percentages. During that same time national gun sales increased dramatically. According to Mr. Lott 450,000 more people bought guns in November 2008 than November 2007 which represents a 40% increase in sales, a trend which continued throughout 2009. The drop in the murder rate was the biggest one-year drop since 1999, another year when gun sales soared in the wake of increased calls for gun control as a result of the Columbine shooting.

In reporting on Lott's original analysis The Chronicle of Higher Education has said that although his findings are controversial "Mr. Lott's research has convinced his peers of at least one point: No scholars now claim that legalizing concealed weapons causes a major increase in crime."

The National Research Council, the working arm of the National Academy of Sciences, claims to have found "no credible evidence" either supporting or disproving Lott's thesis. However, James Q. Wilson wrote a dissenting opinion in which he argued that all of the Committee's own estimates confirmed Lott's finding that right-to-carry laws had decreased the murder rate and most of Lott's statistical analysis was inscrutable and survive virtually every reanalysis done by the committee. On the Ayres and Donohue hybrid model showing more guns-more crime, the NAS panel stated: "The committee takes no position on whether the hybrid model provides a correct description of crime levels or the effects of right-to-carry laws."

A 2008 article by Carlisle E. Moody and Thomas B. Marvell uses a more extensive data set and projects effects of the Ayres and Donohue hybrid model beyond a five-year span. Though their data set renders an apparent reduction in the cost of crime, Donohue and Ayres point out that the cost of crime increased in 23 of the 24 jurisdictions under scrutiny. Florida was the only jurisdiction showing positive effects from Shall-Issue Laws. Donohue and Ayres question the special case of Florida as well.

Using publicly available media reports, the Violence Policy Center claims that from May 2007 through the end of 2009, concealed carry permit holders in the U.S. have killed at least 117 individuals, including 9 law enforcement officers (excluding cases where individuals were acquitted, but including pending cases). There were about 25,000 murders by firearm that period, meaning that concealed carry permit holders committed less than 1% of the murders by firearm. Furthermore, a large number of the victims were killed in extended suicides, most of which took place in the home of the shooter, where arms can be possessed without special permits. VPC also includes in its numbers several homicides using only long guns and several instances of accidental discharge.

According to FBI police crime reports, in 2008 there were 14,180 murders and 616 justifiable homicides (of which 371 were performed by law enforcement) in the United States. However, the FBI Uniform Crime Report states that the justifiable homicide statistic does not represent eventual adjudication by medical examiner, coroner, district attorney, grand jury, trial jury or appellate court; few US jurisdictions allow a police crime report to adjudicate a homicide as justifiable, resulting in an undercount in the UCR table. The vast majority of defensive gun uses (DGUs) do not involve killing or even wounding an attacker, with government surveys showing 108,000 (NCVS) to 23 million (raw NSPOF) DGUs per year, with ten private national surveys showing 764,000 to 3.6 million DGU per year.

In 2009, Public Health Law Research, an independent organization, published an evidence summary concluding there is not enough evidence to establish the effectiveness of "Shall-Issue" laws as a public health intervention to reduce violent crime.