Monday, August 30, 2010

John Howard's greatest gift?

Sydney Morning Herald
200 lives per year. Well done.

Ten years of suicide data in the wake of John Howard's decision to ban and buy back half a million semi-automatic rifles and shotguns has produced a stunning conclusion.

A paper forthcoming in the American Law and Economics Review finds the buyback cut firearm suicides 74 per cent, saving 200 lives per year.

A former Australian Treasury economist Christine Neill, now with Canada's Wilfrid Laurier University says she found the result so surprising she tried to redo her calculations in the hope the effect would be smaller.

"I fully expected to find no effect at all," she told The Age from Waterloo, Ontario. "That we found such a big effect and that it meshed with a range of other data was just shocking, completely unexpected."

John Howard's agreement with the states to ban and buy back more than 600,000 weapons in the wake of the 1996 Port Arthur massacre cut Australia's stock of firearms 20 per cent and roughly halved the number of households with access to guns...

Two of the independent rural MPs now holding the balance of power in the national parliament opposed the plan. Queensland MP Bob Katter said Australia had got "to the ludicrous point of completely disarming the nation" and claimed "everywhere they ban guns the death rates from guns go up". Tony Windsor, then in the NSW parliament, attempted to introduce an amendment that would have registered gun owners rather than firearms.

Dr Neill says while it seems surprising that a 20 per cent cut in the number of firearms would have the number of suicides from firearms 74 per cent, none of her academic colleagues have found fault with her finding.

Her co-author is ANU academic Dr Andrew Leigh, elected his month as a Labor member of parliament representing the ACT.

They used what is known as a difference-in-differences approach, exploiting the fact that some states withdrew guns faster than others and examining whether their firearm suicide rates fell faster.

A previous study had found no nationwide effect, noting that firearm suicides began falling before the buyback.

However Dr Neill and Dr Leigh found that states such as Tasmania which withdrew guns quickly had a much bigger decline in firearm suicides than states such as NSW which withdrew more slowly.

Whereas the earlier study had found an uptick in suicides by other methods, suggesting substitution, Dr Neill's study found no evidence of substitution within any state.

"It is simply not the case that there was an increase in non-firearm suicide deaths in states that brought back more firearms," she told The Age. "I am confident these lives were saved."

Most of Australia's 2100 suicides per year do not involve firearms, making the 200 lives saved as a result of the firearm ban small in relation to total suicides.

But Dr Neill says applying an accepted financial value to each of these human lives results in an economic boost per year of $500 million - an outcome she says represents $800 per weapon destroyed.

"This is clearly one of John Howard's greatest legacies," she told The Age. "Perhaps even one of his greatest economic legacies.

"It also succeeded in its stated goal. Before the buyback Australia used to have a multiple shooting every year or two. In the 13 years since there have been none. I have calculated the probability of that happening by chance - it's extraordinarily low."

Published in today's SMH and Age


"Note that the bump-up in non-firearm suicides seen in the
time series data (Figure 1a) in the 1996–1998 period is not easily
attributable to method substitution or other factors associated with
firearm withdrawals or other changes in firearm legislation that varied at
the state level, since in that case we would expect to see states that had
larger falls in firearm suicide also experience increases in non-firearm
suicide. There is no empirical support for that in the data. The very late
increase in non-firearm suicides in states with higher buyback rates is
somewhat of a mystery. The magnitude of the later increase is two to
five times the magnitude of the relative reduction in firearm suicides in
the same period. Taken at face value as an indicator of method
substitution, it would suggest that individuals only began substituting to
other methods 6 years after the gun buyback and that the rate of
substitution was greater than 100%. It seems unlikely that this is
consistent with any reasonable model of method substitution. It is
possible that this reflects a change in the collection of suicide data post
2002—that possibility is explored in Section 4.1.5."

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