Academic studies that have rejected Lott's conclusions include the following. With the exception of the 2003 study by John J. Donohue, these studies generally contend that there seems to be little or no effect on crime from the passage of license-to-carry laws. Donohue's 2003 study finds an increase in violence. (This is contradicted by Moody and Marvell's September 2008 study in Econ Journal Watch; a response from Donohue and Ayres will be forthcoming in the January 2009 issue.)
Jens Ludwig, Do Permissive Concealed-Carry Laws Reduce Violent Crime? unpublished draft dated Oct. 8, 1996, on file with Albert Alschuler. Ludwig notes a correlation between PPBF4049 (percent of population black, female, aged 40 to 49) and high crime rates in the data used in the Lott & Mustard crime trends regressions. (This factor is found as a correlation, but is not cited in Lott & Mustard 1997 as a causation.)
Albert Alschuler, Two Guns, Four Guns, Six Guns, More Guns: Does Arming the Public Reduce Crime? Valparaiso U Law Rev. Spring 1997. Alschuler notes that while PPBM2029 (as perpetrators of crime) and PPBF64+ (as victims) are strongly correlated to high homicide rates in the dataset used by Lott & Mustard 1997, PPBF4049 is rated more highly as a predictor of homicide rate. Alschuler notes that Lott supplied him with his copy of Ludwig's 1996 paper as well as the Lott & Mustard data.
Franklin Zimring and Gordon Hawkins, Concealed Handguns: The Counterfeit Deterrent, 7 The Responsive Community 2 (Spring 1997). Zimring & Hawkins cite recognition of the legitimacy of defensive gun use as an impediment to the socially desirable goal of eliminating private ownership of handguns and set out to criticise Lott & Mustard.
Both Albert Alschuler and Jens Ludwig note a number of problems in their separate papers. Why, for example, should the concentration of older black women in a population predict higher crime rates in the Lott and Mustard model, but not the increased concentration of young men, age 20 to 29, who are vastly more likely to commit such offenses?
David Hemenway, 'Review of More Guns, Less Crime: Understanding Crime and Gun-Control Laws', New England Journal of Medicine, 1998. Hemenway's review states
Lott finds, for example, that both increasing the rate of unemployment and reducing income reduces the rate of violent crimes and that reducing the number of black women 40 years old or older (who are rarely either perpetrators or victims of murder) substantially reduces murder rates. Indeed, according to Lott's results, getting rid of older black women will lead to a more dramatic reduction in homicide rates than increasing arrest rates or enacting shall-issue laws
Rutgers sociology professor Ted Goertzel stated that "Lott’s massive data set was simply unsuitable for his task", and that he "compar[ed] trends in Idaho and West Virginia and Mississippi with trends in Washington, D.C. and New York City" without proper statistical controls. He alleged that econometric methods are susceptible to misuse and can even become junk science.
Ian Ayres, Yale Law School, and John Donohue, Stanford Law School, 'Shooting Down the More Guns, Less Crime Hypothesis'. Stanford Law Review, 2003.
Jens Ludwig, Georgetown University, "Concealed-Gun-Carrying Laws and Violent Crime: Evidence from State Panel Data", published in International Review of Law and Economics, 1998.
Dan Black and Daniel Nagin, "Do 'Right-to-Carry' Laws Deter Violent Crime?" Journal of Legal Studies, Vol. 27, No. 1, pp. 209-213 (January 1998).
Mark Duggan, University of Chicago, "More Guns, More Crime," National Bureau of Economic Research, NBER Working Paper No. W7967, October 2000, later published in Journal of Political Economy.
Steven Levitt, University of Chicago, 'Understanding Why Crime Fell in the 1990s: Four Factors that Explain the Decline and Six that Do Not'. Journal of Economic Perspectives, 2004. Levitt lists 'Laws allowing a right to carry concealed weapons' as number five in his list of 'Six Factors that Played Little or No Role in the Crime Decline'.
Jeffrey Miron, Boston University, 'Violence, Guns, and Drugs: A Cross-Country Analysis'. The Journal of Law and Economics, October 2001.
Tomislav V. Kovandzic and Thomas B. Marvell, "Right-To-Carry Concealed Firearms and Violent Crime: Crime Control Through Gun Decontrol?" Criminology and Public Policy 2, (2003) pages 363-396.
John J. Donahue III, Stanford Law School, 'The Final Bullet in the Body of the More Guns, Less Crime Hypothesis', Criminology and Public Policy, 2003.