Patterico's Pontifications

6/12/2007

Studies Show the Death Penalty Does Indeed Deter Murders

Filed under: Crime,General — Patterico @ 12:20 am

The AP reports:

[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.

I tend to be skeptical of social science studies like this, and indeed, the article indicates that there is considerable disagreement over the merit of the studies. Unfortunately, it doesn’t provide a way to definitively resolve the question, and I lack the familiarity with the studies or the necessary statistical expertise to make a judgment.

At the very least, this article should prevent death penalty opponents from lazily arguing that there is no scientific support for the proposition that the death penalty deters murders. They are welcome to question the studies, and I would enjoy reading thoughtful criticism along those lines. But they don’t get to claim that there is no evidence to support deterrence, without taking these studies head-on.

For me, the case for the death penalty doesn’t rest on the outcome of studies on general deterrence. It comes primarily from a sense that this penalty is the just result for callous criminals who commit premeditated murder, and secondarily from a concern that murderers can still kill as long as they are alive, whether in prison or not.

But the concept of deterrence is important to many, and with good reason. If these studies are accurate, it spells trouble for death penalty opponents.

Thanks to Christoph.

35 Responses to “Studies Show the Death Penalty Does Indeed Deter Murders”

  1. As a former Investigator/Violent Crime for a state that does not have the death penalty, the studies conclusion is a no brainer for me. The death penalty is a definite deterrent.

    Glenn Beebe (ed5905)

  2. This study simply reiterates what other studies have shown before, and the numerical range of murders prevented per execution is also in line with earlier studies. But the liberal view of execution is that it is never justified, period. So I do not believe this study will change anyone’s mind about capital punishment – opposition to the death penalty is too much a part of the liberal’s concept of self.

    Aside: Some might remember when the feckless Mike Dukakis was asked during a televised debate what he would say if his own wife were the victim of a horrific crime – sensing the trap, he said he still would not want the death penalty. I think millions of men looking on that night intuited (correctly) that the guy was a total weenie, and weenies don’t need to be president. That moment, and the ridiculous picture of the little man in the big tank with the helmet over his ears like a 5 year old T-baller in his too-big batting helmet, sealed his electoral fate, in my mind.

    Jeff Hull (9672ef)

  3. The same guys who will question the study are the ones who hang their approval of minimum wage increases on one of the most dubious and criticized economic studies ever.

    spongeworthy (45b30e)

  4. As far as deterrence goes, I sleep quite soundly knowing that some SOB will never be able to do it again.

    What never seems to be discussed in the MSM is that it is punishment. That is what the criminal justice system was meant to be about. Punishment.

    William Teach (6b9910)

  5. Well one thing is for sure ROBERT ALTON HARRIS,TOOKIE WILLIAMS and TED BUNDY will never kill anyone again and SCREW THE BLEEDINGHEARTS

    krazy kagu (d982eb)

  6. Pro-death-penalty moralists like P and me are going to be happy this helps with the politics, but we’d support it even if the deterrence studies proved the opposite. As it is, they’re icing on the cake.

    Attila (Pillage Idiot) (68fd1f)

  7. This quote amused me:

    “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.”

    I think what he’s saying is that they definitively don’t have enough data to say anything definitive.

    Crust (399898)

  8. “For me, the case for the death penalty doesn’t rest on the outcome of studies on general deterrence. It comes primarily from a sense that this penalty is the just result for callous criminals who commit premeditated murder, and secondarily from a concern that murderers can still kill as long as they are alive, whether in prison or not.”

    I couldn’t agree with you more. I even like the order you put them in.

    Christoph (353eca)

  9. I prefer to think of the death penalty in terms of recompense.

    The interesting question for me is not whether the death penalty is ever justified, but, rather, whether our society should use its ultimate authority in this way. Given other studies at least as good as the ones that Patterico mentioned, that show that the death penalty is sometime unfairly meted out on the basis of race or the competence of legal representation, I would think that while the state should reserve the right to use that punishment, it should refrain in from using it because it can never fairly recompense those to whom it has done an injustice.

    Fritz (45e987)

  10. Dennis Prager was talking about this this morning and gave an example of a society that had the death penalty only on Monday, Wednesday and Friday. I don’t think the deterrence effect is that precise. I think it is a general deterrent but most first degree murders are committed by sociopaths with poor impulse control. The chief benefit is to the gene pool and as a deterrent to in-prison murders. I think taking the murderer off the street comes first. Second is permanence because these sociopaths do not learn to control their impulses with age. Remember that the “Bird Man of Alacatraz” committed another murder in prison. The worst of these murderers are not safe to return to society ever. Execution is permanent. If banning DDT to save pelicans is worth 300 million African children dying of malaria, the risk of executing an innocent man is acceptable.

    Mike K (6d4fc3)

  11. Mike K,

    Both “poor impulse control” and “in-prison murders” as reasons for the death penalty remove moral agency from the person to whom the death penalty has been applied.

    Fritz (45e987)

  12. A society that doesn’t have the will to carry out the ultimate sanction is a society that doesn’t have the will to survive.

    Joe Miller (a85074)

  13. I would think that while the state should reserve the right to use that punishment, it should refrain in from using it because it can never fairly recompense those to whom it has done an injustice.

    If I understand you correctly, because some killers whose victims are white do not get the death sentence, no one should.

    By that reasoning no one should get life either.

    aunursa (1b5bad)

  14. Years ago, W.F. Buckley predicted that those who claim the DP is wrong because it doesn’t deter–and who by implication consider deterrence important–would not change their minds if it were shown to deter.
    Let’s wait and see.

    Richard Aubrey (67d560)

  15. Steve Levitt — an economist who I trust to call it as he sees it (not necessarily the same as getting it right of course) — is not impressed:

    Given the evidence I’ve examined, I believe that Wolfers is on the right side of this debate. There are recent studies of the death penalty — most bad, but some reasonable — that find it has a deterrent effect on crime. Wolfers and John Donohue published an article in the Stanford Law Review two years ago that decimated most of the research on the subject.

    Analyses of data stretching farther back in time, when there were many more executions and thus more opportunities to test the hypothesis, are far less charitable to death penalty advocates. On top of that, as we wrote in Freakonomics, if you do back-of-the-envelope calculations, it becomes clear that no rational criminal should be deterred by the death penalty, since the punishment is too distant and too unlikely to merit much attention. As such, economists who argue that the death penalty works are put in the uncomfortable position of having to argue that criminals are irrationally overreacting when they are deterred by it.

    Crust (399898)

  16. Mike K:

    If banning DDT to save pelicans is worth 300 million African children dying of malaria…

    That’s kind of like saying “if pigs fly…” According to Wikipedia, malaria kills a total of one to three million people a year.

    And with the DDT debate, it’s important to remember that for the most part DDT bans are (and were) bans for agricultural use, not malaria prevention. Using DDT as a broad pesticide promotes DDT resistance in mosquitoes (a major problem in many parts of the world, although there are alternatives). So bans on agricultural use can ultimately save lives.

    Crust (399898)

  17. Sure cuts down on recidivism, anyway. Not so sure about deterrence.

    mojo (8096f2)

  18. I read a lot of quantitative social studies in my work, and believe me, all studies are suspect, in that the researcher is trying to prove something that he or she believes is true. That being said, the hypothesis that the DP deters crime would be automatically suspect in today’s PC climate. No one would question the opposite hypothesis, however, at least no one at AP.

    As for DDT, here’s an African who thinks that the mere 1 million malaria dead should be prevented.
    Give us DDT!

    Patricia (824fa1)

  19. Patricia, I would hope that everyone would like to see all malaria deaths prevented. Or for that matter thinks that talk of a “mere” 1 million dead is callous (yes I realize you meant that as humor).

    Crust (399898)

  20. I would think that while the state should reserve the right to use that punishment, it should refrain in from using it because it can never fairly recompense those to whom it has done an injustice.

    Interesting stance. How would the state fairly recompense someone who was wrongfully convicted of murder and died in prison before he was cleared? How would it recompense someone mistakenly shot and killed by the police?

    Do you not agree that both of those scenarios are not materially different from wrongfully executing someone? Would you admit that there is a way to compensate families of victims of wrongful death?

    By all means, the state should strive to eliminate all possible doubt of guilt before executing. But letting murderers live causes the case of them committing more murders without ever having to pay a higher price than prison.

    Steverino (d27168)

  21. Crust (#15): You quote an economist who argues that “no rational criminal should be deterred by the death penalty, since the punishment is too distant and too unlikely to merit much attention.” And you’re right that the death penalty may be remote and uncertain and entirely theoretical in states like California.

    But where I live — in Houston — it’s none of those things. The thugs and the gang members, the professional criminals and the amateurs — everyone here knows that a conviction for killing a police officer, for example, is genuinely likely to translate into that cold needle within a reasonably short period of time.

    I agree 100% with Patterico that the death penalty can be justified without reference to deterrence. I also agree with critics who contend that deterrence is hard to quantify or prove. But clearly, both retributive justice and deterrence are dis-served in those states where public officials lack the guts and/or competency to enforce their death penalties with regularity. Most of the time, our system works — not perfectly, but then, no system of justice has ever been perfect. And indeed, Texans take the death penalty very seriously here in large part precisely because it’s not hypothetical or remote.

    Beldar (977b40)

  22. Crust,
    You quibbled with this statement:

    If banning DDT to save pelicans is worth 300 million African children dying of malaria…

    because the actual number per year is closer to one million. Over 30 years though the total would be larger. This is off topic…but if you are denying these deaths are linked to the banning of DDT, or denying that criminals understand and fear execution, I don’t know what to say.

    Patricia (824fa1)

  23. This is just one of those no duh kind of things. But again, it really makes no difference, the death penalty is about being the only just punishment for certain heinous crimes, and must be used. In any event Levitt’s conclusions that the death penalty should not deter crime because the execution is so remote is interesting because the studies show that the speed at which the penalty was carried out had a strong deterrent effect. BUT, none of this is the slightest bit new:

    Ecclesiastes 8:11: Because the sentence against an evil deed is not executed quickly, therefore the hearts of the sons of men among them are given fully to do evil.

    JB (7e0e87)

  24. We do need to mandate that DNA evidence is necessary before the death penalty can be imposed. Eye witness accounts are not even trustworthy nor are lie detector tests trustworthy enough to be used as justification to take a person’s life.

    amhcw (f6db75)

  25. amhcw,

    We do need to mandate that DNA evidence is necessary before the death penalty can be imposed.

    How about for Richard Allen Davis? His prints were found in Polly Klaas’ bedroom and he led the police to her corpse.

    I don’t know for sure whether there’s DNA evidence (as the body decomposed for months before being found…the exact cause of death was not determined), but there’s no doubt that Davis did the deed. While I get and agree with your larger point, I also have no qualms about putting this dog down in the absence of DNA evidence.

    Pablo (99243e)

  26. “Mike K,

    Both “poor impulse control” and “in-prison murders” as reasons for the death penalty remove moral agency from the person to whom the death penalty has been applied.

    Comment by Fritz”

    I was not trying to make a moral argument. Feel free to do so. The discussion was about the utility of the death penalty to society.

    As for DDT and the alleged ban for “only agricultural use,” you must not get out much. The number of African children who have died since the 1972 ban is unknown but 300 million is not out of the ballpark. If you prefer, use 30 million. I still know lefties who are arguing that DDT spraying inside homes does not work. You might read the article by the Uganda health minister. This is a hot topic for environmentalists and the fraud that was Rachel Carson’s book has never been refuted successfully. Too many people want to believe. The same is true of Margaret Meade and “Coming of Age in Samoa.” The Samoans played a joke on her and we are all paying the price 80 years later.

    Mike K (86bddb)

  27. If I understand you correctly, because some killers whose victims are white do not get the death sentence, no one should.

    By that reasoning no one should get life either.

    I’m trying to say a few things. First, I would argue that the state has a natural right to punish violators of the law, up to and including the punishment of death.

    Second, the death penalty is an appropriate recompense for certain crimes.

    Third, our ability to apply the death penalty is so biased and broken that we ought to seriously reconsider our process. Any utility gained from the process is lost because of its capriciousness.

    Fourth, while it may be small comfort to give monetary compensation of a man who has been unfairly imprisoned for 20 years, it’s something. For the dead, there is nothing.

    Fifth, in a propositional nation, founded on a principle of inalienable human rights, utility as a justification of the death penalty seems, to me at least, strangely inappropriate.

    Fritz (45e987)

  28. Third, our ability to apply the death penalty is so biased and broken…

    It will always be “broken” because we are but poor fallible humans. Yes, make it as faultless as possible, but don’t throw out the baby with the bath water.

    Patricia (824fa1)

  29. Donohue and Wolfers (and Donohue) have been strongly rebutted:

    (2006) “This analysis shows that attempts to make the deterrence effect disappear are ineffective.” (p 16)
    — Existence of the death penalty, in law, has a statistically significant impact on reducing murders. (p 23)
    — Execution rates show significant impact in reducing murders. (p 13 & 23)
    — Death row commutations, and other removals, increase murders. (p13 & 23)
    — The criticism of our studies is flawed and does not effect the strength of the measured deterrent effect.
    “The Impact of Incentives On Human Behavior: Can we Make It Disappear? The Case of the Death Penalty”, Naci H. Mocan, R. Kaj Grittings, NBER Working Paper, 10/06, www(dot)nber.org/papers/w12631

    (2006) ” . . . (Donohue and Wolfers’ “D&W”) criticisms of Zimmerman’s analysis are misrepresentative, moot or unsupportable in terms of the analyses they perform.” “It is shown that Zimmerman’s published empirical results, or the conclusions drawn from them, are not in any way refuted by D&W’s critique.” (pg 3) “This later estimate suggests that each execution deters 14 murders on average . . .”. (pg 7) “It is shown that D&W made a number of serious misinterpretations in their review of Zimmerman’s study and that none of the analyses put forward by D&W (which ostensibly refute Zimmerman’s original results and conclusions) hold up under scrutiny. (pg8) ” . . . D&W do not even report Zimmerman’s “preferred” results correctly, and then proceed by carrying on this error throughout the remainder of their critique.”(pg8) “Of course, (D&W’s) omission tends to create a strong impression that Zimmerman’s analysis ‘purports to find reliable relationships between executions and homicides’, when his actual conclusions regarding the deterrent effect of capital punishment are far more agnostic.” (pg10) ” . . . D&W’s method of interpreting their results is not consistent with that proscribed by the received econometric literature on randomized testing . . .”. “As such, D&W’s interpretation of their randomized test in itself does not (and cannot) reasonably lead one to conclude that Zimmerman’s estimates suggesting a deterrent effect of capital punishment are spurious.” (pg12) ” . . . D&W do not appear to have interpreted their randomization test in any meaningful fashion.” (pg14) ” . . . the state clustering correction employed by D&W may not be producing statistically meaningful results.” (pg16) “And while D&W once lamented that recent econometric studies purporting to demonstrate a deterrent effect of capital punishment yield ‘heat rather than light’, as shown herein, their criticisms of Zimmerman (2004) tend to yield ‘smoke rather than fire’.”(pg26)
    Zimmerman, Paul R., “On the Uses and ‘Abuses’ of Empirical Evidence in
    the Death Penalty Debate” (November 2006). ssrn(dot)com/abstract=948424

    Dudley Sharp (fc7c50)

  30. I didn’t agree with the studies/survey..Death penalty is definitely deterrent,that is why at least the murders are hiding their faces after committing crimes.Otherwise they feel free to commit crimes and spend some years in the prison…
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    sakthi (52d4ff)

  31. It will always be “broken” because we are but poor fallible humans. Yes, make it as faultless as possible, but don’t throw out the baby with the bath water.

    Comment by Patricia

    The fallibility of human justice goes without saying. However, I think that there is clear evidence that the death penalty is more screwed up than normal human fallibility might lead you to believe.

    Fritz (45e987)

  32. Funny that Fritz hasn’t addressed my comment that (a) we already have a mechanism to compensate those killed wrongfully and (b) someone executed wrongfully (and to the best of our knowledge this has yet to happen) isn’t any more horrendous than someone wrongfully imprisoned and dying therein.

    Steverino (d27168)

  33. Let me clarify: you can’t compensate people who are killed. As I said in a previous comment, we compensate the families of those killed wrongfully.

    I apologize for any confusion I may have caused with #32

    Steverino (d27168)

  34. Does that mean that you don’t think the death penalty is appropriate in cases of felony murder, where there was absolutely no intent to kill, but an intent to commit a robbery very carefully where death to a victim (or even a crime participant) occurs unintentionally? Most capital cases in California flow from felony murders where the special circumstance making a person death eligible is that the murder occurred during the course of an inherently dangerous felony (i.e., the same fact that makes the unintentional killing into a murder in the first place).

    Lloyd Handler (d428d9)

  35. That’s an interesting statistic you claim in your Comment #34, Lloyd. Could you cite even one capital case “where there was absolutely no intent to kill, but an intent to commit a robbery very carefully where death to a victim (or even a crime participant) occur[ed] unintentionally”?

    nk (616f8b)


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