This testimony was
delivered on June 27, 2007, before the Subcommittee on the
Constitution, Civil Rights, and Property Rights of the Committee on
the Judiciary of the United States Senate.
My name is David Muhlhausen. I am Senior
Policy Analyst in the Center for Data Analysis at The Heritage
Foundation. I thank Chairman Russell Feingold, Ranking Member Sam
Brownback, and the rest of the subcommittee for the opportunity to
testify today. The views I express in this testimony are my own and
should not be construed as representing any official position of
The Heritage Foundation.
While opponents of capital punishment have
been very vocal in their opposition, Gallup opinion polls
consistently demonstrate that the American public overwhelmingly
supports capital punishment.
 (See Chart 1.) In Gallup's most recent
poll, 67 percent of Americans favor the death penalty for those
convicted of murder, while only 28 percent are opposed. From 2000
to the most recent poll in 2006, support for capital punishment
consistently runs a 2:1 ratio in favor.
public support for capital punishment, federal, state, and local
officials must continually ensure that its implementation
rigorously upholds constitutional protections, such as due process
and equal protection of the law. However, the criminal process
should not be abused to prevent the lawful imposition of the death
penalty in appropriate capital cases.
The Deterrent Effect
of the Death Penalty
and local officials need to recognize that the death penalty saves
lives. How capital punishment affects murder rates can be explained
through general deterrence theory, which supposes that increasing
the risk of apprehension and punishment for crime deters
individuals from committing crime. Nobel laureate Gary S. Becker's
seminal 1968 study of the economics of crime assumed that
individuals respond to the costs and benefits of committing
deterrence theory, criminals are no different from law-abiding
people. Criminals "rationally maximize their own self-interest
(utility) subject to constraints (prices, incomes) that they face
in the marketplace and elsewhere."
Individuals make their decisions based on the net costs and
benefits of each alternative. Thus, deterrence theory provides a
basis for analyzing how capital punishment should influence murder
rates. Over the years, several studies have demonstrated a link
between executions and decreases in murder rates. In fact, studies
done in recent years, using sophisticated panel data methods,
consistently demonstrate a strong link between executions and
reduced murder incidents.
Research. The rigorous examination of the deterrent effect of
capital punishment began with research in the 1970s by Isaac
Ehrlich, currently a University of Buffalo Distinguished Professor
Professor Ehrlich's research found that the death penalty had a
strong deterrent effect. While his research was debated by other
additional research by Professor Ehrlich reconfirmed his original
In addition, research by Professor Stephen K. Layson of the
University of North Carolina at Greensboro strongly reconfirmed
Ehrlich's previous findings.
Research. Numerous studies published over the past few years,
using panel data sets and sophisticated social science techniques,
are demonstrating that the death penalty saves lives.
Panel studies observe multiple units over several periods. The
addition of multiple data collection points gives the results of
capital punishment panel studies substantially more credibility
than the results of studies that have only single before-and-after
intervention measures. Further, the longitudinal nature of the
panel data allows researchers to analyze the impact of the death
penalty over time that cross-sectional data sets cannot
Using a panel data
set of over 3,000 counties from 1977 to 1996, Professors Hashem
Dezhbakhsh, Paul R. Rubin, and Joanna M. Shepherd of Emory
University found that each execution, on average, results in 18
Using state-level panel data from 1960 to 2000, Professors
Dezhbakhsh and Shepherd were able to compare the relationship
between executions and murder incidents before, during, and after
the U.S. Supreme Court's death penalty moratorium.
They found that executions had a highly significant negative
relationship with murder incidents. Additionally, the
implementation of state moratoria is associated with the increased
incidence of murders.
Professor Shepherd's analysis of monthly data from 1977 to 1999
found three important findings.
execution, on average, is associated with three fewer murders. The
deterred murders included both crimes of passion and murders by
executions deter the murder of whites and African-Americans. Each
execution prevents the murder of one white person, 1.5
African-Americans, and 0.5 persons of other races.
shorter waits on death row are associated with increased
deterrence. For each additional 2.75-year reduction in the death
row wait until execution, one murder is deterred.
Professors H. Naci
Mocan and R. Kaj Gittings of the University of Colorado at Denver
have published two studies confirming the deterrent effect of
capital punishment. The first study used state-level data from 1977
to 1997 to analyze the influence of executions, commutations, and
removals from death row on the incidence of murder.
For each additional execution, on average, about five murders were
deterred. Alternatively, for each additional commutation, on
average, five additional murders resulted. A removal from death row
by either state courts or the U.S. Supreme Court is associated with
an increase of one additional murder. Addressing criticism of their
Professors Mocan and Gittings conducted additional analyses and
found that their original findings provided robust support for the
deterrent effect of capital punishment.
Two studies by
Paul R. Zimmerman, a Federal Communications Commission economist,
also support the deterrent effect of capital punishment. Using
state-level data from 1978 to 1997, Zimmerman found that each
additional execution, on average, results in 14 fewer murders.
Zimmerman's second study, using similar data, found that executions
conducted by electrocution are the most effective at providing
Using a small
state-level data set from 1995 to 1999, Professor Robert B. Ekelund
of Auburn University and his colleagues analyzed the effect that
executions have on single incidents of murder and multiple
incidents of murder.
They found that executions reduced single murder rates, while there
was no effect on multiple murder rates.
In summary, the
recent studies using panel data techniques have confirmed what we
learned decades ago: Capital punishment does, in fact, save lives.
Each additional execution appears to deter between three and 18
murders. While opponents of capital punishment allege that it is
unfairly used against African-Americans, each additional execution
deters the murder of 1.5 African-Americans. Further moratoria,
commuted sentences, and death row removals appear to increase the
incidence of murder.
The strength of
these findings has caused some legal scholars, originally opposed
to the death penalty on moral grounds, to rethink their case. In
particular, Professor Cass R. Sunstein of the University of Chicago
recent evidence of deterrence is shown to be correct, then
opponents of capital punishment will face an uphill struggle on
moral grounds. If each execution is saving lives, the harms of
capital punishment would have to be very great to justify its
abolition, far greater than most critics have heretofore alleged.
capital punishment for two good reasons. First, there is little
evidence to suggest that minorities are treated unfairly. Second,
capital punishment produces a strong deterrent effect that saves