Is it a Deterrent?
Answering the hard questions: Deterrence
“I have inquired for most of my adult life about studies that might show that the death penalty is a deterrent. And I have not seen any research that would substantiate that point.” -U.S. Attorney General Janet Reno, January 21, 2000
Consider the following:
Generally, states without the death penalty have consistently lower murder rates than states with the death penalty. A New York Times review in 2000 of murder rates over the past 20 years found that the murder rate in states with the death penalty has been 48% to 101% higher than in non-death penalty states.
Consistent with previous years, the 2006 FBI Uniform Crime Report showed that the South had the highest murder rate and accounts for over 80% of the executions in the nation. The Northeast, which has less than 1% of executions, again had the lowest murder rate.
The U.S. with the death penalty has a much higher murder rate than countries in Europe which do not have the death penalty.
According to a survey of the former and present presidents of the nation’s top academic criminological societies, 88% of these experts rejected the notion that the death penalty acts as a deterrent to homicide. (“Do Executions Lower Homicide Rates? The Views of Leading Criminologists,” Northwestern University School of Law’s Journal of Criminal Law and Criminologyby Professor Michael Radelet and Traci Lacock, June 2009).
Some studies have shown a reverse deterrent effect, or brutalization effect, associated with the death penalty. Murders in some jurisdictions increased in the periods following well publicized executions, just the opposite of what a deterrent effect would produce.
Researchers Find Flaws in Studies Claiming Deterrent Effect
In an article entitled, “The Death Penalty: No Evidence for Deterrence,” John Donohue and Justin Wolfers examined recent statistical studies that claimed to show a deterrent effect from the death penalty. The authors conclude that the estimates claiming that the death penalty saves numerous lives “are simply not credible.” In fact, the authors state that using the same data and proper methodology could lead to the exact opposite conclusion: that is, that the death penalty actually increases the number of murders. The authors state: “We show that with the most minor tweaking of the [research] instruments, one can get estimates ranging from 429 lives saved per execution to 86 lives lost. These numbers are outside the bounds of credibility.”
The authors conclude that the evidence of deterrence is far too weak to rely on as a justification for the death penalty:
The view that the death penalty deters is still the product of belief, not evidence. The reason for this is simple: over the past half century the U.S. has not experimented enough with capital punishment policy to permit strong conclusions. Even complex econometrics cannot sidestep this basic fact. The data are simply too noisy, and the conclusions from any study are too fragile. On balance, the evidence suggests that the death penalty may increase the murder rate although it remains possible that the death penalty may decrease it. If capital punishment does decrease the murder rate, any decrease is likely small.
John Donohue is a professor at Yale Law School and a Research Associate at the National Bureau of Economic Research. Justin Wolfers is a professor at the Wharton School of Business and a Research Affiliate at the National Bureau of Economic Research. (The Economists’ Voice, April 2006).