Not All Right-To-Carry Laws Are The Same, Yet Much Of The Literature Keeps Ignoring The Differences
John R. Lott Jr.
Crime Prevention Research Center
September 5, 2014
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Econ Journal Watch, Vol 12(3), September 2015
Unfortunately, many who have examined the impact of so-called “shall-issue” or “right-to-carry” laws assume that the adoption of such laws causes a large, immediate increase in the number of permits. But that is often not the case, for states differ widely as to how easily permits can be obtained. This problem is particularly problematic for studies that have looked at the period after 2000. In fact, the share of the adult population with permits increased less during the 1999-2010 period in the states that adopted right-to-carry laws than the states that they are being compared against.
Not All Right-To-Carry Laws Are The Same, Yet Much Of The Literature Keeps Ignoring The Differences – Introduction
Making more arrests or imposing more severe criminal penalties make it riskier for criminals to commit crimes. Are criminals deterred as well by allowing potential victims better means to defend themselves?
The academic literature assumes that state adoption of so-called “right-to-carry” or “shall-issue” laws results in relatively more people carrying concealed handguns, compared to the states that they are being compared against. Yet, that isn’t always the case (Lott, 2000, 2010, and 2012).
Many who have empirically examined the impact of these laws assume that these laws are the same across states and over time. The laws are not the same, however, because states differ widely as to how easily permits can be obtained. The differences affect not only the immediate increase in permits after the laws are adopted, but also the growth in permits over time. Failing to take these differences into account results in inaccurate measurement of the laws’ impact on crime.
The problem proves particularly troublesome in recent research by Mark Gius (2014), Carlisle Moody et al. (2014), Paul Zimmerman (2014), and Abhay Aneja et al. (2014), all of whom extended the data past the late 1990s. Gius examines data from 1980 to 2009, Moody et al. from 1977 to 2006, and Zimmerman and Aneja et al. both study the laws in the years from 1999 to 2010. In all these panel data studies, it is assumed that the states that are adopting right-to-carry laws during their sample periods are seeing the biggest increases in concealed handgun permits. The other states – both those that adopted right-to-carry laws prior to the beginning of the sample and those with more restrictive concealed carry laws (so-called “May issue” states) – are assumed to have relatively smaller increases in permits. If that wasn’t the assumption, there would be no reason to expect that panel studies would find a drop in crime rates for states that adopted right-to-carry laws during the sample periods. But no explanation is provided for such an assumption about rates of permitting. As we will see, sometimes the opposite is true.
The authors with the shortest time periods have their reasons. Zimmerman uses the period of time he does only because other data that he was using to measure private law enforcement activity were limited to those years. Aneja et al. also exclude the earlier data “to remove the confounding influence of the crack cocaine epidemic”, though even the research that they cite indicates that the impact of the epidemic had ended even for blacks by 1995, thus well before 1999.3 Excluding more than twenty years of data also seems a rather extreme solution to dealing with the impact of cocaine on crime rates, as there are variables and approaches that allow one to directly account for the impact of cocaine.
Here I focus focus on Zimmerman (2014), both because of the short time period that it examines and because it is published. But our discussion applies as well to the other papers, though its import varies in each case.5 Studies with data covering a long time period, such as Gius (2014)6 and Moody et al. (2014), which found that right-to-carry reduce violent crime, face some bias against finding that result, but it is clearly a much bigger problem for Zimmerman (2014). The same goes for Aneja et al. (2014), an unpublished working paper; that paper provides the only reported claim that right-to-carry laws increase murder rates, a finding that would disappear if they included data prior to 1999.
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