Advocates of the death penalty will be shocked by Levitt and Dubner's evidence that it has had no deterrent effect on the murder rate in the US. They explain this very simply: not enough people are executed, even in America, for the death penalty to produce any change in the behaviour of anyone contemplating murder. In the US as a whole, only two per cent of criminals waiting on death row can expect to be executed in any given year (it makes death row a lot safer than being a crack dealer in Chicago, where the risk of death is more than three times as high). Some states have reinstituted capital punishment and then not executed anyone. New York state, for instance, brought back capital punishment, with much political and media fanfare, in 1995. But since then, not a single criminal has been executed.
Levitt and Dubner conclude that the death penalty in the US is "an empty threat... no reasonable criminal should be deterred by it". They leave open the disturbing possibility that, if the US courts did start killing people at a much higher rate, it would have an effect on reducing crime. In discussing the failure of America's meagre controls on purchasing guns to have any effect at all on the penetration of gun ownership, the authors note that "If the death penalty were assessed to anyone carrying an illegal gun, and if the penalty were actually enforced, gun crimes would surely plunge." The authors do not say whether or not they think this would be a sensible policy.
Levitt—and the arguments are almost all his: Dubner is his amanuensis—insists that increased rates of imprisonment do reduce crime. He says the figures make that conclusion irresistible: the late 1960s, when American politicians started to send far fewer people to jail, were, as he puts it "a great time to be a criminal". Criminals were smart enough to work out that they faced dramatically reduced risks of punishment. The result was a crime boom, which was not tackled until politicians decided that prison was effective after all. Today, four times as many Americans are in prison as were incarcerated in 1972. Having risen inexorably until the early 1990s, crime in America is now at the level it was in the late 1950s.
Increased use of prison is one part of the explanation for America's spectacular, and enviable, fall in crime. So is the increase in police numbers. Levitt, however, doesn't think that more prisons and more police officers can be the whole explanation for the halving of America's rate of violent crime. The search for a further factor brings Levitt to his most controversial thesis: his suggestion that perhaps one third of the fall in crime is attributable to the legalisation of abortion in America in 1970.
my decisions on anything is hardly from emotional perspective. 