Death Penalty Deters Murders, Studies Say
Hotly Debated Academic Analyses Claim Up To 18 Lives Saved Per Execution
NEW YORK, June 11, 2007
(AP) Anti-death penalty forces have gained momentum in the past few years, with a moratorium in Illinois, court disputes over lethal injection in more than a half-dozen states and progress toward outright abolishment in New Jersey.
The steady drumbeat of DNA exonerations — pointing out flaws in the justice system — has weighed against capital punishment. The moral opposition is loud, too, echoed in Europe and the rest of the industrialized world, where all but a few countries banned executions years ago.
What gets little notice, however, is a series of academic studies over the last half-dozen years that claim to settle a once hotly debated argument — whether the death penalty acts as a deterrent to murder. The analyses say yes. They count between three and 18 lives that would be saved by the execution of each convicted killer.
The reports have horrified death penalty opponents and several scientists, who vigorously question the data and its implications.
So far, the studies have had little impact on public policy. New Jersey's commission on the death penalty this year dismissed the body of knowledge on deterrence as "inconclusive."
But the ferocious argument in academic circles could eventually spread to a wider audience, as it has in the past.
"Science does really draw a conclusion. It did. There is no question about it," said Naci Mocan, an economics professor at the University of Colorado at Denver. "The conclusion is there is a deterrent effect."
A 2003 study he co-authored, and a 2006 study that re-examined the data, found that each execution results in five fewer homicides, and commuting a death sentence means five more homicides. "The results are robust, they don't really go away," he said. "I oppose the death penalty. But my results show that the death penalty (deters) — what am I going to do, hide them?"
Statistical studies like his are among a dozen papers since 2001 that capital punishment has deterrent effects. They all explore the same basic theory — if the cost of something (be it the purchase of an apple or the act of killing someone) becomes too high, people will change their behavior (forego apples or shy away from murder).
To explore the question, they look at executions and homicides, by year and by state or county, trying to tease out the impact of the death penalty on homicides by accounting for other factors, such as unemployment data and per capita income, the probabilities of arrest and conviction, and more.
Among the conclusions:
Each execution deters an average of 18 murders, according to a 2003 nationwide study by professors at Emory University. (Other studies have estimated the deterred murders per execution at three, five and 14).
The Illinois moratorium on executions in 2000 led to 150 additional homicides over four years following, according to a 2006 study by professors at the University of Houston.
Speeding up executions would strengthen the deterrent effect. For every 2.75 years cut from time spent on death row, one murder would be prevented, according to a 2004 study by an Emory University professor.
In 2005, there were 16,692 cases of murder and non-negligent manslaughter nationally. There were 60 executions.
The studies' conclusions drew a philosophical response from a well-known liberal law professor, University of Chicago's Cass Sunstein. A critic of the death penalty, in 2005 he co-authored a paper titled "Is capital punishment morally required?"
"If it's the case that executing murderers prevents the execution of innocents by murderers, then the moral evaluation is not simple," he told The Associated Press. "Abolitionists or others, like me, who are skeptical about the death penalty haven't given adequate consideration to the possibility that innocent life is saved by the death penalty."
Sunstein said that moral questions aside, the data needs more study.
Critics of the findings have been vociferous.
Some claim that the pro-deterrent studies made profound mistakes in their methodology, so their results are untrustworthy. Another critic argues that the studies wrongly count all homicides, rather than just those homicides where a conviction could bring the death penalty. And several argue that there are simply too few executions each year in the United States to make a judgment.
"We just don't have enough data to say anything," said Justin Wolfers, an economist at the Wharton School of Business who last year co-authored a sweeping critique of several studies, and said they were "flimsy" and appeared in "second-tier journals."
"This isn't left vs. right. This is a nerdy statistician saying it's too hard to tell," Wolfers said. "Within the advocacy community and legal scholars who are not as statistically adept, they will tell you it's still an open question. Among the small number of economists at leading universities whose bread and butter is statistical analysis, the argument is finished."
Several authors of the pro-deterrent reports said they welcome criticism in the interests of science, but said their work is being attacked by opponents of capital punishment for their findings, not their flaws.
"Instead of people sitting down and saying 'let's see what the data shows,' it's people sitting down and saying 'let's show this is wrong,"' said Paul Rubin, an economist and co-author of an Emory University study. "Some scientists are out seeking the truth, and some of them have a position they would like to defend."
The latest arguments replay a 1970s debate that had an impact far beyond academic circles.
Then, economist Isaac Ehrlich had also concluded that executions deterred future crimes. His 1975 report was the subject of mainstream news articles and public debate, and was cited in papers before the U.S. Supreme Court arguing for a reversal of the top U.S. court's 1972 suspension of executions. (The court, in 1976, reinstated the death penalty.)
Ultimately, a panel was set up by the National Academy of Sciences which decided that Ehrlich's conclusions were flawed. But the new pro-deterrent studies have not gotten that kind of scrutiny.
At least not yet. The academic debate, and the larger national argument about the death penalty itself — with questions about racial and economic disparities in its implementation — shows no signs of fading away.
Steven Shavell, a professor of law and economics at Harvard Law School and co-editor-in-chief of the American Law and Economics Review, said in an e-mail exchange that his journal intends to publish several articles on the statistical studies on deterrence in an upcoming issue.
Hmmm, I'm totally sceptical, aside from the fact that I am against the death penalty on principle.
How do you draw a line of causality from an execution to potentially averted homicides? I guess I'd need to read the report in full.
As far as I can see this is entirely about statistics. These stats don't seem to be very robust.
Mike
The best way to avoid murders and criminal activity in general is to create a good, working society. If you have a good happy life you don't ruin it all killing someone, do you?
Quote from: 71 dB on June 11, 2007, 06:49:18 AM
The best way to avoid murders and criminal activity in general is to create a good, working society. If you have a good happy life you don't ruin it all killing someone, do you?
To a large extent, but it seems there are is a certain group of people whose brains are simply defective and who will go berserk even in a nominally normal situation, like the moron who killed 30 people at Virginia Tech.
Quote from: head-case on June 11, 2007, 06:53:44 AM
To a large extent, but it seems there are is a certain group of people whose brains are simply defective and who will go berserk even in a nominally normal situation, like the moron who killed 30 people at Virginia Tech.
Yes, we'll always be stuck with the nutcases - but nobody could possibly argue that the death penalty has a deterrent effect on
them!
Btw, I gather from the info that they found a rise in homicides after a ban on the death penalty. But crime is on the rise continuously. I would be much more convinced by the opposite: a
decline in homicides after a (re)introduction of the death penalty. And even than it could be argued that any decline is caused by longer jail sentences which often accompany such a measure (people in jail can't murder anybody, the longer they are in jail - the less murders you have...)
Q
A few linked studies will not change my position on the Dealth Penalty. I, too oppose it on principle
D minor,
I see this is an AP article. Is there a link to the original study? This is literally the opposite of what prior studies were saying. It would be interesting to see their methodology. Stats are only as good as the questions you're asking.
Quote from: Steve on June 11, 2007, 07:03:56 AM
A few linked studies will not change my position on the Dealth Penalty. I, too oppose it on principle
Agreed. But proponents keep telling it is an effective measure against crime and therefore necessary.
Maybe they should compare US crime statistics with European statistics. Could be very interesting..... 8)
Q
Quote from: Que on June 11, 2007, 07:12:55 AM
Agreed. But proponents keep telling it is an effective measure against crime an therefore necessary.
Maybe they should compare US crime statistics with European statistics. Could be very interesting..... 8)
Q
Indeed. This coming from the nation with the world's largest prison population... I fully intend to be a European in a few years... :)
Suppose somebody force a person to lay down
on a stretcher; tie his hands and foot so as
he can't move, and inject in his veins a lethal
liquid solution,killing the guy slowly.
In any state,that act is considered a first grade
murder with sadism and perfidy.
But if it's the state that do exactly that, you call
it justice?
IMO there's no difference between a sadistic
degenerate murder, and the executioners of
the prison.
Quote from: head-case on June 11, 2007, 06:53:44 AM
To a large extent, but it seems there are is a certain group of people whose brains are simply defective and who will go berserk even in a nominally normal situation, like the moron who killed 30 people at Virginia Tech.
Well, perfect society is an utopia but if there are hard and soft ways to reduce homisides I vote for the soft ones. Criminals are often victims of circumstancies themselves and while should be punished for the crimes committed should also be treated as human beings.
Death penalty has zero effect on those who go beserk and kill themselves after the blood bath.
Quote from: carlos on June 11, 2007, 07:23:30 AM
Suppose somebody force a person to lay down
on a stretcher; tie his hands and foot so as
he can't move, and inject in his veins a lethal
liquid solution,killing the guy slowly.
In any state,that act is considered a first grade
murder with sadism and perfidy.
But if it's the state that do exactly that, you call
it justice?
IMO there's no difference between a sadistic
degenerate murder, and the executioners of
the prison.
That is why no moral society would ever entertain such a practice. But, wait the US does... :(
Quote from: 71 dB on June 11, 2007, 07:36:21 AMDeath penalty has zero effect on those who go beserk and kill themselves after the blood bath.
There are those who don't have the decency to kill themselves.
Quote from: head-case on June 11, 2007, 06:53:44 AM
To a large extent, but it seems there are is a certain group of people whose brains are simply defective and who will go berserk even in a nominally normal situation, like the moron who killed 30 people at Virginia Tech.
No doubt. I'd wager that close to 100% of all seriel killers have a genetic brain defect (which may be triggered by environmental factors) or lived under extreme conditions (such as recurring sexual abuse) in their adolescence.
It has very little to do with their economic circumstances.
Quote from: O Mensch on June 11, 2007, 07:10:30 AM
D minor,
I see this is an AP article. Is there a link to the original study? This is literally the opposite of what prior studies were saying. It would be interesting to see their methodology. Stats are only as good as the questions you're asking.
Here's the original article ...... (http://www.cbsnews.com/stories/2007/06/11/national/main2911428.shtml) I didn't see any links .......
Quote from: Que on June 11, 2007, 07:01:33 AM
but nobody could possibly argue that the death penalty has a deterrent effect on them!
Yes, it's tough to take a sampling of would-be murderers and ask them: "what's the reason you didn't follow through with the murder? Was it the threat of the death penalty?"
Quote from: 71 dB on June 11, 2007, 07:36:21 AM
Death penalty has zero effect on those who go beserk and kill themselves after the blood bath.
100% true.
Many murderers have a latent death wish, in which case the death penalty could actually be an
inducement (unbeknownst to them) !
Quote from: carlos on June 11, 2007, 07:23:30 AM
Suppose somebody force a person to lay down
on a stretcher; tie his hands and foot so as
he can't move, and inject in his veins a lethal
liquid solution,killing the guy slowly.
In any state,that act is considered a first grade
murder with sadism and perfidy.
But if it's the state that do exactly that, you call
it justice?
IMO there's no difference between a sadistic
degenerate murder, and the executioners of
the prison.
Of all the arguments against the death penalty, I think this has to be the weakest. There are any number of acts which if done by a private citizen are a crime, yet legal by the government. By this logic, we need to abolish imprisonment since this is obviously kidnapping & vigilantism, taxes since they are of course robbery, and vehicle impoundment since this is certainly grand theft auto, not to mention extortion...
Quote from: Novitiate on June 11, 2007, 06:20:14 AM
How do you draw a line of causality from an execution to potentially averted homicides? I guess I'd need to read the report in full.
This is the fundamental weakness of any statistical regression model. You can find a
correlation with statistical methods, but you can't "point the causal arrow". However, this would seem like one case where it is pretty hard to argue that the arrow points in the opposite direction. One would have to believe that fewer murders or murderers somehow lead to stricter death penalty laws, tougher judges and juries, etc.
Quote from: knight on June 11, 2007, 06:31:16 AM
As far as I can see this is entirely about statistics. These stats don't seem to be very robust.
Mike
Just so.
Perhaps they should go out and execute people at random and see whether there is any change in the statistics.
Oh, they do...
It seems that murdering private citizens is a State's
prerogative. That's the theory of Adolf and Joseph.
All you need is a law allowing it. And if later on you
find that the victim was Innocent, you always can
apologize. Or not at all. After all, you can invoke
"national security" reasons.
Quote from: Redbeard on June 11, 2007, 09:07:01 PM
This is the fundamental weakness of any statistical regression model. You can find a correlation with statistical methods, but you can't "point the causal arrow". However, this would seem like one case where it is pretty hard to argue that the arrow points in the opposite direction. One would have to believe that fewer murders or murderers somehow lead to stricter death penalty laws, tougher judges and juries, etc.
Or there could quite simply be a host of other variables at play that the statistcs don't test and don't reflect. You can't just look at two variables and try to figure out which one is cause and effect unless you have definitively shown that no other variable has an impact on your data.
I am very skeptical of any research that purports to "prove" that an execution means that 5 or 10 or any random number of murders in the future will not occur. I don't believe that anyone murders in contemplation of the death penalty. More likely, a murder is done impulsively which means that the killer isn't thinking about consequences. If someone plans a murder, they go to great lengths to prevent their arrest and conviction, whether the penalty is death or imprisonment. In fact, those who commit murder by design usually do it because they feel they won't get caught, not that if they are caught they might get the death penalty rather than life in prison. The logic just doesn't hold water for a study like that! The one thing I have learned in my life is that statistics and data can be manipulated to support numerous and contradictory conclusions depending on who is doing the analysis.
That doesn't mean that I am completely opposed to the death penalty, but I see it as a form of justice, not as a deterrent. Frankly, there are crimes that are so hideous, and those that commit them are so incapable of redemption, that I don't have a shred of compunction in sending them to death row. I just want to be very sure that the man who gets executed really did commit the crime and so far our legal system hasn't proved to be flawless. Or, I would prefer that the burden of proof in death penalty cases be higher than for other criminal cases, beyond reasonable doubt must become without any doubt.
Quote from: O Mensch on June 12, 2007, 01:05:03 PM
Or there could quite simply be a host of other variables at play that the statistcs don't test and don't reflect. You can't just look at two variables and try to figure out which one is cause and effect unless you have definitively shown that no other variable has an impact on your data.
True. I'm sure they looked at quite a few variables beyond the two being discussed (demographic make up, etc), but this doesn't mean they didn't miss something. I don't know anything about this study beyond the reference in the OP, and honestly don't plan on changing that. However, if the study methodology is otherwise sound (proper sampling, design, etc), then critics should really either offer a plausible explanation of why lower murder rates might cause a tougher criminal justice system (seems unlikely), or suggest what untested variable might have explained this apparent correlation.
Quote from: Bunny on June 12, 2007, 01:41:57 PM
That doesn't mean that I am completely opposed to the death penalty, but I see it as a form of justice, not as a deterrent.
This is why in the end the study cited is really meaningless. Those who support the death penalty do so because they feel it is just, and those who oppose it do so because they feel it is unjust. No amount of study regarding deterrence will change most people's position. I happen to support the death penalty (like you with reservations about the possibility of executing the innocent), and I also happen to believe that there is some deterrent value to it. However, these two beliefs don't have to go hand in hand. Alternately, if I believed it was unjust I could still believe in a deterrent effect and not support it.
took 'em long enough to figure out the correlation.
Quote from: MahlerTitan on June 12, 2007, 03:09:13 PM
took 'em long enough to figure out the correlation.
If there really is a correlation. More likely, the study was framed in such a way so that the results would support the thesis. I'm sure that the anti-death penalty lobby could fund another study as well done that would show that the death penalty actually encourages murder (kill the witnesses to the crime, kill accomplices, etc.), and another group could find the stats to show that there is no correlation at all. Social science is not hard science. For a study like this there are no controls, so the results of statistical analysis need to be so strong that they cannot be denied.
The easiest way to test this theory is to ask if the murder rate in countries that don't have the death penalty is higher than in countries that do. Is the murder rate in Great Britain substantially higher than in the USA? I'll bet it's not, and in UK, there is no death penalty. Is the murder rate in Russia where they have the death penalty lower than in the Netherlands where they don't have the death penalty? Have the rates of violent crime risen in UK and France as a result of eliminating the death penalty? Do more Swedes commit murder than Egyptians because there is no death penalty in Sweden and there is a death penalty in Egypt?
After someone demonstrates that the murder rates in Sweden, UK, Netherlands, France, Spain, Belgium, Italy, et al. are higher than in Virginia, New Jersey, Georgia, Alabama, North Carolina, New York or California then perhaps I'll give some serious consideration to this study. Until then, it's just words written on paper to advance a political agenda.
Why don't they study whether an absence of guns in the general population has any effect on the murder rate? For me it seems that there would be a far more obvious connection here?
Which goes to show that this is a heavily politically biased study.
Quote from: erato on June 13, 2007, 01:31:58 AM
Why don't they study whether an absence of guns in the general population has any effect on the murder rate?
There are many. One study concludes "that many lives would be saved if all states increased their level of control to that of New Jersey, the state having the most stringent gun control laws." (http://www.saf.org/LawReviews/GeiselEtAl.htm)
See also, e.g., Murray, Handguns, Gun Control Laws and Firearm Violence, 23 SOC. PROB. 81, 88-91 (1975); Cook, The Effect of Gun Availability on Violent Crime Patterns, 455 ANNALS 63 (1981); Zimring, Is Gun Control Likely to Reduce Violent Killings?, 35 U. CHI. L. REV. 721 (1968).
Thanks! Still I notice no lack of guns chez the Sopranos.....
Quote from: erato on June 13, 2007, 04:17:04 AM
Thanks! Still I notice no lack of guns chez the Sopranos.....
Yes, but there is no chez Soprano anymore -- and who even knows why...
what next? whether incarceration deters crime?
Quote from: MahlerTitan on June 13, 2007, 07:42:34 PM
what next? whether incarceration deters crime?
Some would argue that it doesn't but others would say, so what if it doesn't because it is a punishment.