Saturday, November 17, 2007

Capital Punishment: More Con from Econometrics

Mark Thoma and I are both opposed to capital punishment. Mark points to some new ”evidence” that capital punishment deters murder:

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.

To paraphrase John Edwards, we’ve seen this movie before.

Jeffrey Fagan of Columbia Law School offered some interesting testimony a couple of years ago:

Recent studies claiming that executions reduce murders have fueled the revival of deterrence as a rationale to expand the use of capital punishment. Such strong claims are not unusual in either the social or natural sciences, but like nearly all claims of strong causal effects from any social or legal intervention, the claims of a “new deterrence” fall apart under close scrutiny. These new studies are fraught with technical and conceptual errors: inappropriate methods of statistical analysis, failures to consider all the relevant factors that drive murder rates, missing data on key variables in key states, the tyranny of a few outlier states and years, and the absence of any direct test of deterrence. These studies fail to reach the demanding standards of social science to make such strong claims, standards such as replication and basic comparisons with other scenarios. Some simple examples and contrasts, including a careful analysis of the experience in New York State compared to others, lead to a rejection of the idea that either death sentences or executions deter murder … In 1975, Professor Isaac Ehrlich published an influential article saying that during the 1950s and 1960s, each execution averted eight murders. Although Ehrlich’s research was a highly technical article prepared for an audience of economists, its influence went well beyond the economics profession … Over the next two decades, economists and other social scientists attempted (mostly without success) to replicate Ehrlich's results using different data, alternative statistical methods, and other twists that tried to address glaring errors in Ehrlich’s techniques and data. The accumulated scientific evidence from these later studies also weighed heavily against the claim that executions deter murders.

Dr.Fagan calls this research junk science but where have I heard of Ehrlich's results. Could it be when Ed Leamer was presenting his Let’s Take the Con Out of Econometrics? Mark says:

This is easy for me. It doesn't matter whether the research on the issue is valid or not. I'm against the death penalty.

Dr. Fagan would likely add that this new research is likely no more valid that the rest of the junk science we have seen.


Bruce Webb said...

"I do believe that people respond to incentives"

Yeah like eliminating witnesses. I support the death penalty for a narrow range of murder crimes. Washington State actually does a pretty good job. We have few executions but nobody gets railroaded here like you often see in Texas.

As an example we had a guy pull a gun on a blind friend in that friend's house, kill him, then call 911, and then gun down the Deputy when he responded. Well lets just say that we didn't have a lot of candlelit vigils the night of the execution (though the guy may have died waiting).

The problem comes when you extend the death penalty beyond murder, the deterrence to following up on a rape by killing the victim is reduced to some degree by the increased probability of getting away with the crime. That is the result may be statistically significant but still not morally acceptable, a decrease in male homicide rates might be offset by an increase in murder-rape.

It is kind of how I feel about Iraq. The logic of fight them over there so that we don't fight them here privileges the value of my life in ways that I don't find acceptable, I have a problem with my country killing women and children in my name on the off chance that it might save me from a terrorist act.

Studies like this show why it is often a good thing to keep economists out of policy shops. Everything tends to get reduced to high level efficiency, while equity and social morality somehow don't make it to the table.

Shane Taylor said...

Albert Camus, in "Reflections on the Guillotine," argued that murderers fear the death penalty after the verdict, but not before the crime. In which case, the incentive would be: don't get caught.

Camus also argued that no human passion is so weak that it cannot, when roused, overcome the fear of death. That won't fit in the straight-jacket binary of Self-Interest/Altruism, so I expect it would be a hard sell for most economists (no offense to present company intended).

Shane Taylor said...

From my Dallas birth until June of last year, I lived in Texas. So, as for the death penalty, I recommend the caustic A Handbook on Hanging.

Shag from Brookline said...

Might the death penalty or castration deter the humongous financial crimes that have robbed so many innocent victims of millions, billions of dollars plus much sorrow?

Myrtle Blackwood said...

An interesting article describing the usefulness of 'econometrics' in Australia for the Federal election campaign. [Australians vote on 24th November 2007].

The Australian Liberal Government's 'Workchoices' effectively reduced award working conditions and wages for the most disadvantaged workers.

It's also clear that the Murdoch Press are no longer supporting the Howard Coalition Government. This may have something to do with Murdoch's extremely belated acknowledgement of the dangers of global warming.

Econometrics equals tricks
Ross Gittins. November 19, 2007

"IT'S probably not possible to estimate with any accuracy the effect that Work Choices has had on employment, productivity, economic growth, inflation or anything else over the 20 months of its existence.

But that hasn't stopped a few sympathetic economists from making dodgy calculations, nor employer groups and Liberal politicians from using and misusing those guesses...

Myrtle Blackwood said...

Bruce said: "I support the death penalty for a narrow range of murder crimes..."

When the forensic science is so bad?

FBI's Forensic Test Full of Holes Lee Wayne Hunt is one of hundreds of defendants whose convictions are in question now that FBI forensic evidence has been discredited.
By John Solomon Washington Post Staff Writer
Sunday, November 18, 2007; Page A01

Anonymous said...

The one persistent and over riding issue with capital punishment is the abysmal record of our criminal justice system in identifying the difference between the guilty and the not guilty. Juries may be repsponsible for the verdict, but a system with a demonstrably lousy record is responsible for presenting the facts of a case. One innocent person executed for a crime is one too many. There is not one person involved in a capital case that can be relied upon to have no ulterior motive. The records speak for themselves, and, by the way, George Bush's Texas is a prime example of criminal justice gone to hell.

Bruce Webb said...

Brenda I wouldn't support these kind of cases. I don't want to get into the details of the relatively few death row criminals in this state, lets just say that the story I cited is the least sickening and nobody doubts that we got the right guys. None of them were convicted on the base of this kind of forensic evidence.

Washington State isn't Texas.

Anonymous said...

But Bruce you're relying on the unfalibility of a system rife with opportunities for error. And what's so bad (or good from the convicted person's perspective) about life in prison without any possibility of parole? It costs less than a capital prosecution, and it's not as barbaric, but still barbaric enough to be close to hell on earth. I trust no one on such an issue.

Anonymous said...

Oops! Sorry, that should be "infalibility."

Eleanor said...

One thing that needs to be studied is how many people who commit serious crimes have a history of closed head injuries. There are brain traumas which make ordinary mental functioning, including impulse control, impossible. We are going to be seeing these problems in the returning Iraq vets, so this is a good time to learn about brain trauma. A recent study of the homeless in Minnesota found 30% had experienced at least one head injury. (Not that the homeless are criminal, but they may have some problems with social skills and organizing their lives.)(By serious crimes, I mean blue collar crimes. White collar crimes do far more harm, but are punished much more lightly. I suspect white collar criminals have other problems.)

ProGrowthLiberal said...

Eleeanor - excellent! You would make a far better econometrician than those whose day job is doing econometrics on such topics - topics they don't seem to quite understand.

Anonymous said...

I fully agree. I would like to see corporate fraud which results in the lose of millions to both workers and investors be reclassified as a capital offense. My personal hero, Robespierre, made excellent use of this concept. He understood very well that if you don't nip a problem in the bud it will bloom again. So he got a little carried away. Therein lies the absurdity of capital punishment. Who is to decide the nature of the crime that will qualify for irreversible punishment?

Anonymous said...


Truth to tell, I am not innocent,
Though I do not believe a dissolute
Slacker from the fraternity, as went
Even to highest office, earns repute.

It is exactly true that an ideal
Has been disrupted--even more, destroyed--
By obvious lies proclaimed with brute force real
Enough to make us skeptics paranoid.

The grand extenuations, even more
The circumambulations as required
To make believe a threat posed at our door
When it was our own falsehood which conspired--

These even from the earliest existed
Beyond the realm of reason: we believed
Politically expedient lies, resisted
Not flattery, so our own selves deceived.

Reagan began it, as his eyes did mist
As he encouraged folks to take their eye
Off from the ball, and capturing his gist
So his successors worked their villainy.

It was a shell game: we believed ourselves
As good beyond the common run of man,
But in such hubris Satan dwells and delves,
While these were hardly Christian, partisan

To greed as thoughtful words you have composed
Clearly point out. Today upon the past
Idealism the way is clearly closed,
And you have given thanks justly aghast.

Repealing of a lie but warrants thanks,
And from your honesty--if with drawn swords--
Perhaps the future will see drawn the ranks
Of new idealists. Thank you for your words.