Another Guest Post from David Garrett:
Correlation causation and crime – the effect of active policing and sentence enhancement
When I was in parliament I sometimes had coffee with Rick Barker, a fellow member of the Law and Order Select Committee and a damn good bloke. Rick told a great story illustrating how correlation and causation can be confused – even by those who should know better.
During WW II, no bananas were imported into Britain, they presumably being deemed not to be an essential food, or just not readily available. After the war, banana imports resumed – and it was noted that within nine months or a year, the birth rate had sharply increased. For a time, banana sales went through the roof, as its “aphrodisiac” qualities became widely known. It was apparently some years – and after a couple of studies found no basis for bananas enhancing fertility – before it was realized that banana imports and rising birth rates were just a coincidence. The birth rate had risen not because of bananas, but because at the same time more and more young men were “de-mobbed” and came home to their wives and girlfriends.
When crime plummeted in New York State following the introduction of “broken windows” policing, those on right said smugly that the reduction in crime followed logically from more intensive policing. Those on the left said falling crime rates were just like those banana imports – changes in policing policy had nothing to do with it.
While it is now pretty much over in the US, for ten or fifteen years the debate raged, with lefties “feverishly searching for the ‘real’ reason crime rates plummeted”, to quote the late Dennis Dutton. Any reason would do - because surely it couldn’t be simple old style policing. Could it?
All sorts of “reasons” were suggested to explain away the precipitate drop in crime, from “demographic bubbles” passing through the population, to the crack epidemic which had been plaguing New York and other states waning . And of course the now famous “more readily available abortions” theory suggested by economist Steven Levitt. This theory of cause and effect is in Levitt’s ‘Freakonomics’ and his paper “Understanding why crime fell in the 1990’s: four factors that explain the decline and six that do not.” in ‘Journal of Economic Perspectives’ Vo. 18, 1: pp. 163-190
Leftist commentators always focus on the “more readily available abortions” factor Levitt identifies without ever mentioning two things: that the abortion ‘factor’ is number four on his list of four; and the two factors to which Levitt ascribes most of the reduction are more police per capita, and much greater use of punitive sentencing policies. While almost every one knows New York is the home of “zero tolerance policing” a.k.a. “broken windows”, it is less well known that New York state also has “sentence enhancement” laws, of which three strikes is one variant.
While lefties often derisively refer to the US experience, I suggest we can learn a lot from that country – both what works and what doesn’t. Those who have traveled widely in the US quickly realize that to a considerable extent it is a land of fifty different nations. The Boston Brahmins have about as much in common with the good old boys of Louisiana and Tennessee as New Zealand’s effete artistic elite have with banana growers in Far North Queensland.
So what does the US experience tell us about how best to reduce crime? The most obvious lesson is that a combination of more police on the streets and sentence enhancement of one sort or another makes the biggest impact. This is the major lesson from the New York experience; it is that state which has seen -by a considerable margin – the greatest reduction in crime of all types since the 1990’s.
Secondly, sentence enhancement works. Levitt himself, the darling of the left – at least on this issue – says so himself. Twenty six states have introduced “three strikes” laws which vary widely in their ambit and effect. Some states – such as California – use their laws far more than others do. With a couple of exceptions, there appears to be a close correlation between the usage of three strikes laws and the level of crime reduction: those states that apply their laws more have seen much greater reductions in crime of all types than those states which do not.
For the left, this is of course an “inconvenient truth” to borrow from Al Gore, but it is a truth nevertheless. It has often been said – including by commenters here on Whaleoil – that the drop in crime across the US, and in other countries in the western world is “unexplained”. What they really mean is if you discount the obvious, then no-one can agree on any other explanation.
Those with both common sense and a degree or two find the lessons from the US clear: put more police on the streets and lock serious felons up for longer, and crime will drop. In the last two years we have introduced a three strikes law, and put more police on the streets of South Auckland which has the highest levels of crime in the country. And as a result, those crime rates are falling, along with prisoner numbers. God help us if the socialists get their hands on the levers of power in 2014.