Publication Bias and Death Penalty Reporting
Courtesy of Justin Wolfers:
The front page of Sunday’s New York Times contained an interesting article reviewing research linking the death penalty to homicide trends. Adam Liptak attempts to provide a balanced account of the debate, noting first one set of findings:
According to roughly a dozen recent studies, executions save lives. For each inmate put to death, the studies say, 3 to 18 murders are prevented.
And then my own research:
The death penalty “is applied so rarely that the number of homicides it can plausibly have caused or deterred cannot reliably be disentangled from the large year-to-year changes in the homicide rate caused by other factors,” John J. Donohue III, a law professor at Yale with a doctorate in economics, and Justin Wolfers, an economist at the University of Pennsylvania, wrote in the Stanford Law Review in 2005. “The existing evidence for deterrence,” they concluded, “is surprisingly fragile.”
Surely a dozen studies is itself evidence of robustness. Why then is then is it that we find these results are fragile? Two words: Publication bias (also known as the file drawer problem). . . .
As I said before, there are all kinds of problems with the research and valuations that go on here. Besides the valuations I mentioned before and the continuing use of shoddy data to confirm an apparent mass predisposition to kill in cold blood, most people are incredibly bad at looking at other alternatives, e.g. increased spending on police, education, family support, and other things, deficiencies of which seem to cause an increased chance of a life of crime. Plus, such things have other positive externalities besides satisfying an antiquated morality quenching the thirst for revenge.
