First one recent research summary:

Half a billion dollars spent buying back hundreds of thousands of guns after the Port Arthur massacre had no effect on the homicide rate, says a study published in an influential British journal. The report by two Australian academics, published in the British Journal of Criminology, said statistics gathered in the decade since Port Arthur showed gun deaths had been declining well before 1996 and the buyback of more than 600,000 mainly semi-automatic rifles and pump-action shotguns had made no difference in the rate of decline.

The only area where the package of Commonwealth and State laws, known as the National Firearms Agreement (NFA) may have had some impact was on the rate of suicide, but the study said the evidence was not clear and any reductions attributable to the new gun rules were slight. "Homicide patterns (firearm and non-firearm) were not influenced by the NFA, the conclusion being that the gun buyback and restrictive legislative changes had no influence on firearm homicide in Australia," the study says.

In his first year in office, the Prime Minister, John Howard, forced through some of the world's toughest gun laws, including the national buyback scheme, after Martin Bryant used semi-automatic rifles to shoot dead 35 people at Port Arthur. Although furious licensed gun-owners said the laws would have no impact because criminals would not hand in their guns, Mr Howard and others predicted the removal of so many guns from the community, and new laws making it harder to buy and keep guns, would lead to a reduction in all types of gun-related deaths.

One of the authors of the study, Jeanine Baker, said she knew in 1996 it would be impossible for years to know whether the Prime Minister or the shooters were right. "I have been collecting data since 1996 . The decision was we would wait for a decade and then evaluate," she said. The findings were clear, she said: "The policy has made no difference. There was a trend of declining deaths that has continued." Dr Baker and her co-author, Samara McPhedran, declared their membership of gun groups in the article, something Dr Baker said they had done deliberately to make clear "who we are" and head off any possible criticism that they had hidden relevant details. The significance of the article was not who had written it but the fact it had been published in a respected journal after the regular rigorous process of being peer reviewed, she said.

Politicians had assumed tighter gun laws would cut off the supply of guns to would-be criminals and that homicide rates would fall as a result, the study said. But more than 90 per cent of firearms used to commit homicide were not registered, their users were not licensed and they had been unaffected by the firearms agreement. Dr Baker said many more lives would have been saved had the Government spent the $500 million on mental health or other programs rather than on destroying semi-automatic weapons. She believed semi-automatic rifles should be available to shooters, although with tight restrictions such as those in place in New Zealand.

The director of the NSW Bureau of Crime Statistics, Dr Don Weatherburn, said he was not surprised by the study. He said it showed "politicians would be well advised to claim success of their policies after they were evaluated, not before".


And now a second recent research summary

The risk of dying by gunshot has dropped dramatically since the gun buyback scheme was introduced after the Port Arthur massacre in 1996, a new report says. Dr Philip Alpers, a University of Sydney academic who helped write the report, said the buyback saw the number of gun deaths a year fall from an average of 521 to 289, "suggesting that the removal of more than 700,000 guns was associated with a faster declining rate of gun suicide and gun homicide".

The Prime Minister, John Howard, introduced some of the world's toughest gun laws after the massacre, forcing people to surrender semi-automatic rifles, which reload each time the trigger is pulled, and pump-action shotguns.

The new report, titled Australia's 1996 Gun Law Reforms: Faster Falls in Firearm Deaths, Firearm Suicides and a Decade without Mass Shootings, finds that in the 18 years before the gun buyback there were an average of 492 firearm suicides a year. After the introduction of the buyback scheme, that figure dropped to 247 in the seven years for which reliable figures are available. The report also found the rate of gun homicides fell from an annual average of 93 in the 18 years before 1996 to an annual average of 56.

The latter finding contrasts with a report published in October which found that half a billion dollars spent removing guns had virtually no effect on homicide rates. That report - by two Australian academics, Jeanine Baker and Samara McPhedran, and published in the British Journal of Criminology - said gun homicide deaths were falling well before the buyback and the rate of decline hardly changed with the new laws.

Dr Simon Chapman, another author of the latest study, agreed that the rate of gun homicide was falling before the buyback. He said that while the rate had risen since then, the numbers involved were so small they were not statistically significant. The most important impact of the buyback was that there had been no mass shootings. He said 112 people had been killed in 11 mass shootings in the 10 years up to Port Arthur, and removing the semi-automatic weapons used in those shootings was a principal aim of the policy. It was "bordering on academic dishonesty" for Dr Baker and Ms McPhedran not to have included that fact in their paper, he said.

The director of the NSW Bureau of Crime Statistics, Dr Don Weatherburn, said that while the two papers might seem to be in conflict, they were not. "Both found that the rate of gun suicide declined faster after the gun buyback and neither found any significant difference in the rate of decline in gun homicide before and after the gun buyback," he said. "The Chapman paper points out that there has been no mass shooting since the gun buyback. The earlier paper should have mentioned this, but didn't. "The results on gun suicide and mass shootings are enough reason to be very cautious about reducing the restrictions on gun ownership."


One look at the graph reproduced above tells you all you need to know. Despite clever use of colours, it is clear that the red line (gun deaths) could best be summarized by a straight line -- in other words no effect of the new gun restrictions. So the major conclusion of the research summarized immediately above is simply a statistical fiddle.

The secondary conclusions -- that gun suicides have declined -- tells us nothing useful unless suicides overall have declined -- and that is carefully not mentioned. If people now are more likely to suicide by jumping in front of trains, is that an improvement?

The third point about mass murders is based on a very small sample size and such samples very often produce unreplicable results. In my own research, I have seen hugely high (and statistically significant) effects drop to negligibility by moving from a small sample to a large one.

I might add that this study adds further to the reputation for medical journals in general and British medical journals in particular to publish results on the basis of their political correctness rather than for their statistical rigor. My Food & Health Skeptic blog repeatedly draws attention to dodgy medical statistics and it was another British medical journal that published the scientifically ludicrous estimates of Iraqi civilian deaths.

It might be noted that generalizations about guns from the USA to Australia and vice versa are risky. Unlike the USA, Australia does not have a large violence-prone black population so few Australians feel the need to own a gun for personal protection. Gun ownership or not does therefore not prove much in Australia. It might also be noted that the Australian gun laws have large loopholes so that anyone who really wants to own a gun can in fact do so legally. A certain Australian person I know owns three Browning machine-guns legally! Beat that!


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