Sunday, 10 August 2014

Guns, suicide, crime

It would seem obvious that if you have fewer guns in people's hands you would get fewer suicides and less crime. But is life that simple? After reading a couple of article by Mark Gius, Professor of Economics at Quinnipiac University, Hamden, Connecticut, USA, I'm beginning to think not. In a recent article in "Significance: statistics making sense", a magazine from The Royal Statistical Society, Gius writes, with regard to gun-related murder rates in the US,
In one of the more recent studies [Gius (2014)], I attempted to determine if assault weapons bans and concealed carry laws had any effects on gun-related murder rates. I decided to focus on these two types of laws because they have changed the most over the past thirty years. I used data for the period 1980–2009, which is one of the longest time periods examined in any research on assault weapons bans or CCW laws. Using the gun-related murder rate as the dependent variable was important because most other studies looked at violent crime rates or homicide rates. Violent crime rate data is not disaggregated into gun-related and non-gun-related violent crime, and homicides include justifiable killings and state-sanctioned killings; hence, an analysis using these types of crime rates may result in spurious conclusions. After analysing the data, I found that states that had more restrictive CCW laws had higher murder rates than states with more permissive CCW laws and that assault weapons bans had no significant effects on murder rates at the state level.

The lack of an affect on the part of state level assault weapons bans was not unexpected: as mentioned previously, very few murders are committed using assault weapons. The higher murder rates during the federal assault weapons ban probably reflected the inadequacy of the federal law and the overall higher crimes rates of that period due to the crack epidemic of the late 1980s and early 1990s.

The concealed carry results, however, were somewhat unexpected. States with more restrictive CCW laws had gun-related murder rates that were 10% higher (p < 0.01). At first sight this would seem to support the deterrent effect hypothesis of many gun rights proponents. There may, of course, be other explanations for these results. Laws may be ineffective due to loopholes and exemptions. The most violent states may also have the toughest gun control measures. Nonetheless, the results of my study do suggest that the potential deterrent effect of concealed weapons should not be ignored.
In another paper, Gius (2011), Gius has also looked at the relationship between gun ownership and suicides. Using recent data on suicide rates, gun control measures, and gun ownership rates, Gius's study suggests that states that require handgun permits have lower gun-related suicide rates, and states that have higher gun ownership rates have higher gun-related suicide rates. Which is what you may expect. Regarding non-gun suicides, results suggest that stricter gun control laws may result in higher non-firearm suicides, and higher rates of gun ownership result in lower non-gun suicide rates. These results suggest that stricter gun control laws may actually induce potential suicide victims to alter the method by which they commit suicide. That is, there is substitution effect. Hence, the overall effects of firearm availability on suicides may be muted due to the fact that while reduced firearm availability reduces firearm suicides, it also increases non-firearm suicides.

  • Gius, M. (2014) "An examination of the effects of concealed weapons laws and assault weapons bans on state-level murder rates". Applied Economics Letters, 21(4), 265–267.
  • Gius, M. (2011) "The Effects of Gun Ownership Rates and Gun Control Laws on Suicide Rates". New York Economic Review, vol. 42, Fall

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