In the current debate on imposing even more infringements on the right to keep and bear arms than already exist, reference is often made to the Australian gun confiscation scheme that was put into effect in 1996. While the results of the scheme have been subject to argument, with papers showing both no effect, small overall increases in crime, and small decreases in homicide, proponents have claimed that the confiscation and ban are responsible for the lack of mass shootings since 1997.
I have found only one paper on the subject;
Mass shootings in Australia and New Zealand: A descriptive study of incidence, by Samara McPhedran and Jeanine Baker, pulblished in the Justice Policy Journal, Vol. 8, No. 1, Spring 2011
Here is the abstract from the paper:
The development of legislation aimed at reducing the incidence of firearm-related death is an ongoing interest within the spheres of criminology, public policy, and criminal justice. Although a body of research has examined the impacts of significant epochs of regulatory reform upon firearm-related suicides and homicides in countries like Australia, where strict nationwide firearms regulations were introduced in 1996, relatively little research has considered the occurrence of a specific type of homicide: mass shooting events. The current paper examines the incidence of mass shootings in Australia and New Zealand (a country that is socioeconomically similar to Australia, but with a different approach to firearms regulation) over a 30 year period. It does not find support for the hypothesis that Australia’s prohibition of certain types of firearms has prevented mass shootings, with New Zealand not experiencing a mass shooting since 1997 despite the availability in that country of firearms banned in Australia. These findings are discussed in the context of social and economic trends.
The focus of the paper, mass shootings, falls in the trap of looking only at shooting incidents. This approach is fundamentally flawed because of the possibility of substitute methods. It does not matter to the person murdered if they are killed with a gun, petrol bomb, or knife. For public policy, it is overall homicide rates that are important, not the type of instrument used. Still the study has useful information not available elsewhere.
I found particularly interesting the fact that mass shootings are extremely rare events. They were even rarer before the modern era of gun regulation and mass media. Only one was noted in Australia before 1980, that one occurred in 1971. One was found in New Zealand, that occurred in 1941. During that time period, gun regulations were far less stringent than they are today.
The paper merely notes the study of the "copycat effect" induced by media coverage; the focus is on the incidence of mass shootings.
Since 1980, 12 mass shootings occurred in Australia and 4 in New Zealand, about the same when corrected for population differences. Most of the mass shootings were domestic, 8 of the 12 in Australia, 2 of the 4 in New Zealand. New Zealand has significant ownership of the firearms banned in Australia. Neither country has has a mass shooting since 1997.
I recommend the study to anyone interested in criminology, mass killings, or citizen disarmament.