In the United States, a right-to-carry law (sometimes abbreviated RTC law, also known as a shall-issue law) is one that requires that governments issue concealed carry handgun permits to any applicant who meets the necessary criteria. These criteria are: the applicant must be an adult, have no significant criminal record, and no history of mental illness, and successfully complete a course in firearms safety training (if required by law).
In 1997, John Lott and David Mustard published an influential study analyzing data from all 3,054 United States counties in The Journal of Legal Studies. The study concluded that right-to-carry laws deterred violent crime, "without increasing accidental deaths". In the study, Lott and Mustard also stated that right-to-carry concealed handgun laws were "the most cost-effective method of reducing crime thus far analyzed by economists." The following year another study was published in the same journal which re-analyzed Lott and Mustard's data and concluded that there was "no basis for drawing confident conclusions about the impact of right-to-carry laws on violent crime." Also that year, a study in the American Economic Review found that the effects of concealed handgun laws on crime rates were much smaller than estimated by Lott and Mustard, and that these effects were not negative with respect to all types of crime. For example, the study found that such laws reduced murder only by, at most, a small amount, and that many states' robbery rates increased after these laws were passed. A 2003 study found that the Lott and Mustard study inappropriately used a dummy variable, leading to misspecification, and, based on a different method of analysis, concluded that the effects of these laws varies from county to county and from state to state and "are not crime-reducing in most cases".
A 2002 study found no evidence that right-to-carry laws either increased or decreased the number of mass shootings.
Another study, published in 2001, found that right-to-carry laws "appear to have statistically significant deterrent effects on the numbers of reported murders, rapes, and robberies." In 2004, a report by the National Research Council concluded that there was insufficient evidence to conclude whether there was a cause-and-effect relationship between RTC laws and crime rates. A 2005 study, looking at every American city with a population of at least 100,000 in 1990, found no evidence that these laws affected violent crime rates either. Another 2005 study reported that RTC laws were associated with higher homicide rates, but that this association was not statistically significant. A 2011 study concluded that the most consistent finding from analyses conducted over the 1977-2006 period was that after RTC laws are adopted, aggravated assault increases, though the researchers noted even this finding was not uniform.
- National Research Council Committee on Law and Justice (2004). Firearms and Violence: A Critical Review. National Academy of Sciences. pp. 120–151.
- Lott, Jr., John R.; Mustard, David B. (January 1997). "Crime, Deterrence, and Right‐to‐Carry Concealed Handguns". The Journal of Legal Studies. 26 (1): 1–68. doi:10.1086/467988.
- Mooney, Chris (13 October 2003). "Double Barreled Double Standards". Mother Jones. Retrieved 13 June 2016.
- Black, Dan A.; Nagin, Daniel S. (January 1998). "Do Right-to-Carry Laws Deter Violent Crime?". The Journal of Legal Studies. 27 (1): 209. doi:10.1086/468019.
- Dezhbakhsh, Hashem (May 1998). "Lives Saved or Lives Lost? The Effects of Concealed Handgun Laws on Crime". The American Economic Review. 88 (2): 468–474. JSTOR 116969.
- Rubin, Paul H; Dezhbakhsh, Hashem (June 2003). "The effect of concealed handgun laws on crime: beyond the dummy variables". International Review of Law and Economics. 23 (2): 199–216. doi:10.1016/S0144-8188(03)00027-9.
- Duwe, G.; Kovandzic, T.; Moody, C. E. (1 November 2002). "The Impact of Right-to-Carry Concealed Firearm Laws on Mass Public Shootings". Homicide Studies. 6 (4): 271–296. doi:10.1177/108876702237341.
- Plassmann, Florenz; Tideman, T. Nicolaus (October 2001). "Does the Right to Carry Concealed Handguns Deter Countable Crimes? Only a Count Analysis Can Say". The Journal of Law & Economics. 44 (S2): 771. doi:10.1086/323311.
- Kovandzic, T. V. (1 November 2005). "The Impact of "Shall-Issue" Concealed Handgun Laws on Violent Crime Rates: Evidence From Panel Data for Large Urban Cities". Homicide Studies. 9 (4): 292–323. doi:10.1177/1088767905279972.
- Rosengart, M (1 April 2005). "An evaluation of state firearm regulations and homicide and suicide death rates". Injury Prevention. 11 (2): 77–83. doi:10.1136/ip.2004.007062.
- Aneja, A.; Donohue, J. J.; Zhang, A. (29 October 2011). "The Impact of Right-to-Carry Laws and the NRC Report: Lessons for the Empirical Evaluation of Law and Policy". American Law and Economics Review. 13 (2): 565–631. doi:10.1093/aler/ahr009.