[Vision2020] Study says Death Penalty IS a Deterent

[Andreas Schou]

Aha.

I think I understand, having read both of the main papers cited. There are
two topics of discussion here:

(1) The Naci Moran study, which was conducted on the 1977-1997 dataset.

and

(2) An Emory University metastudy of other death penalty studies conducted
on the 1977-1997 dataset.

There are several exceptional factors in this dataset in particular. First,
that between 1972 and 1976, all death sentences were commuted by the Supreme
Court's decision that the death penalty was, in all cases, unconstitutional.
Second, that between 1977 and 1997, there was a sharp general decline in the
crime rate, including murder. Third, that Texas performed just over one
third of all executions in the United States.

This introduces substantial distortions into any study of the data.

First, in January 1977, the only Americans currently on Death Row were
Americans convicted in late 1976. The death penalty can take close to a
decade to execute -- you're looking at most death penalties in 1976 actually
being executed in the early 1980s. For this reason, this particular dataset
contains exactly zero executions over the period with the greatest crime
rate, with a slow increase (due to the lag in execution) over the duration
of the dataset. As there are no claims made that the death penalty has a
general deterrent effect on crimes not punishable by death, then it would
seem that there are two synchronous but not correlated events here: an
increase in executions following a favorable Supreme Court decision, and a
decrease in the general crime rate.

Second, death penalties -- even in the case of murder -- constitute a very
small fraction of the total sentences handed down. Examining the death
penalty without regard to variables correlated to the likelihood of a death
penalty being executed ignores the deterrent effects of changes in
sentencing. It is not unreasonable, for instance, to believe that a state's
willingness to execute the death penalty is correlated with the severity of
its sentencing guidelines for murder.

Third, Texas. 1/3 of the executions from that dataset occurred in Texas.
Variations in Texas policy, Texas demographics, and Texas sentencing
guidelines exercise an effect truly disproportionate to the population of
the state.

If you want to read about the methodological problems with drawing
conclusions about murder in particular based on that dataset, you can read
(essentially) the article I cribbed my response from here:

http://repositories.cdlib.org/cgi/viewcontent.cgi?article=1059&context=uclastat

-- ACS
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