In 1764, a young Italian economist, Cesare Bonesana,
the Marquis of Beccaria, wrote An Essay on Crimes and Punishments.
The slim volume, almost unknown today, held ideas that were revolutionaryso
radical, in fact, that Beccaria initially published An Essay without attaching his name to it.
With time, however, many of Beccaria's ideas about criminal justice
would become widely accepted in Europe and the United States, incorporated
whole cloth into penal codes and constitutions. That defendants
should be given a speedy trial, heard by a jury of peers, judged
on evidence rather than gossip, and without coerced testimony, were
among the innovations proposed by Beccaria. But a central proposition
of Beccaria's essaythat the death penalty be abolishedwas
then, and remains still, a highly contentious idea.
At the heart of his argument was the concept of deterrence, the
linchpin of economic theories of crime. Beccaria's theory of punishment
explicitly assumed that people make rational economic choices about
whether to violate laws based on their comparison of the costs and
benefits of doing so. Punishments therefore should be designed so
as to minimize the net benefit of committing crimes. "That
a punishment may produce the effect required," he wrote, "it
is sufficient that the evil it occasions should exceed the good
expected from the crime, including in the calculation the certainty
of the punishment, and the privation of the expected advantage.
All severity beyond this is superfluous, and therefore tyrannical."
Execution is a less effective deterrent than life imprisonment,
according to Beccaria, because it exacts a lower cost from a lawbreaker.
"The death of a criminal is a terrible but momentary spectacle,"he
wrote at a time when public hangings were a matter of course. "And
therefore [it is] a less efficacious method of deterring others
than the continued example of a man deprived of his liberty, condemned
as a beast of burden."
Even a cold-blooded murderer will be deterred by the prospect of
a life without freedom; the price is just too high. "There
is no man who, upon the least reflection, would put in competition
the total and perpetual loss of his liberty, with the greatest advantages
he could possibly obtain in consequence of crime," Beccaria
argued. And unending incarceration, he felt, was more costly than
death itself. "Perpetual slavery, then, has in it all that
is necessary to deter the most hardened and determined, as much
as the punishment of death. Indeed, I say it has more. There are
many who can look upon death with intrepidity and firmness, some
through fanaticism and others through vanity, which attends us even
to the grave."
Was Beccaria right? Is the death penalty comparatively powerless?
Is life imprisonment more effective? These are questions that seem
empirically testable, open to verification or refutation through
careful analysis of data. By looking at statistics on capital crimes,
death row executions and whatever other variables might be thought
to factor into crime levels in a given society, answers could be
found. And indeed, social scientists have been engaged for decades
in efforts to measure the deterrent effect of capital punishment.
But as revealed in the conflicting results of two studies released
this past year by economists from Harvard, the University of Chicago
and the University of Colorado, the questions remain stubbornly
resistant to resolution.
Modern analysis of capital punishment
Though much of Beccaria's legal theory found widespread acceptance, the
economic analysis of crime and punishment on which it rested remained
in obscurity for centuries. Jeremy Bentham elaborated on Beccaria's economic
ideas in the early 1800s, but most later discussions of crime, and of
murder in particular, relied on psychological, sociological and even phrenological
theories. By and large, these theories dismissed the idea that threat
of execution might effectively dissuade a potential murderer: most murders
were impulsive, not planned. And if other social scientists were dismissive
of capital punishment, the term evoked nothing for economists but concern
over capital gains taxation.
But Gary Becker's 1968 analysis, "Crime and Punishment: An Economic
Approach," resurrected the lost idea that criminals might rationally
weigh the costs and benefits of committing a crime. "Lest the reader
be repelled by the apparent novelty of an 'economic' framework for illegal
behavior," wrote Becker in the conclusion of his seminal article,
"let him recall that two important contributors to criminology during
the eighteenth and nineteenth centuries, Beccaria and Bentham, explicitly
applied an economic calculus." (See interview with Gary Becker in this issue of The Region.)
While Becker provided the first modern economic framework for the supply
and demand of crime, echoing Beccaria's thoughts in many passages, his
work didn't examine Beccaria's claim about the ineffectiveness of the
death penalty. It fell to Isaac Ehrlich, a colleague of Becker at the
University of Chicago, to put the question to a careful empirical test.
Ehrlich's 1975 analysis, "The Deterrent Effect of Capital Punishment:
A Question of Life and Death," published soon after the U.S. Supreme
Court's 1972 ruling that prohibited capital punishment, used Becker's
general model to derive a specific "murder supply function."
Like any conventional production function, Ehrlich's equation said that
the number of murders "supplied" would be a function of numerous
cost variables, especially those related to the direct cost (to the criminal)
of committing a murder (that is, the probabilities of arrest, conviction
Also included were variables to measure the resources allocated by society
to deter crime (e.g., per capita expenditures on police). Still other
variables covered economic variables that might measure the opportunity
costs of committing a crime (e.g., unemployment rate, per capita income)
as well as demographic variables (e.g. racial composition, age distribution).
Using regression analysis on U.S. data from 1933 to 1967, Ehrlich was
able to estimate the independent effect of each of these variables on
the number of murders committed.
The results were stunning. "On the average," wrote Ehrlich,
"the tradeoff between the execution of an offender and the lives
of potential victims it might have saved was on the order of magnitude
of 1 for 8." Eight lives saved by one deatha result Beccaria
would never have imagined.
Ehrlich cautioned that the results didn't imply capital punishment is
necessarily a desirable form of punishment. Levels of alternative punishments
for murder may not be optimal, he noted, and murders "may also be
reduced through increased employment and earning opportunities."
But death penalty proponents were elated by the analysis. And Robert Bork,
then solicitor general, brought Ehrlich's study to the attention of the
Supreme Court in arguing that the death penalty should be reinstated.
In 1976, the Court so ruled.
But Ehrlich's findings were quickly challenged. Several economists said
Ehrlich's sample had too little variation in arrest, conviction and execution
rates to truly measure their effect on murder rates. Many argued that
Ehrlich had excluded important variables (e.g., length of sentence, gun
ownership, deaths at the hands of police), which negated the deterrent
effect of prisoner executions once they were incorporated into the model.
Economists Peter Passell and John Taylor, then at Columbia University,
were two of the more prominent critics of Ehrlich's work. They pointed
out that his results were highly sensitive to how different variables
were defined and to the statistical form of equation used to relate variables.
Without prior guidance from theory on which format or definitions to use,
there was no way to judge which was most valid, and therefore no reason
to believe in one set of results or another. "The results are sensitive
to specification of the variables and transformation of the data,"
wrote Passell and Taylor. "This sensitivity raises grave (and in
our own opinion, overwhelming) doubt about the utility of Ehrlich's time-series
estimates." Even more crucially, perhaps, Passell and Taylor showed
that Ehrlich's deterrent results disappeared if just the last seven years
of the 34-year sample period were excluded from analysis.
Though not entirely devastating, the flood of critiques was enough to
throw Ehrlich's seemingly unambiguous findings into significant doubt.
The many studies that followed have clarified, corrected and elaborated
the impact of various factors on murder rates, but none has provided a
definitive answer to the question of the deterrent impact of capital punishment.
"By the end of the century," wrote Stuart Banner, professor
of law at Washington University, in his 2002 book, The Death Penalty:
An American History, "there was an abundant literature in journals
of academic law and economics. A few studies found a deterrent effect,
but most did not." Battles raged over methodology and there remained
"a nagging suspicion" that researcher beliefs affected research
outcomes. "This diversity in academic opinion translated poorly into
the public policy arena, where proponents of each side tended to ascribe
validity only to those studies which supported their own view."
A fresh look
Into this clouded arena have stepped two new studies. The first,
by economists Lawrence Katz of Harvard University, Steven Levitt
at the University of Chicago and Ellen Shustorovich of the Monitor
Co., examines crime rates in relation to execution rates and prison
conditions. The second, by H. Naci Mocan, chair of the economics
department at the University of Colorado at Denver, and R. Kaj
Gittings, a graduate student in the department, looks at homicide
rates relative to executions and pardons of prisoners on death
In "Prison Conditions, Capital Punishment, and Deterrence,"
Katz, Levitt and Shustorovich start from the perspective that
prison conditions are more likely than executions to have a deterrent
effect on crime, including homicide. In the second half of the
20th century, executions were relatively rare and they occurred
only after a long lag from the actual commission of the crime;
the murders themselves were often perpetrated under the influence
of alcohol or drugs. The impact on criminal decision-making of
such a low probability, highly time-discounted outcome, suggest
the authors, was likely to be minimal.
After all, they point out, the execution rate on death row (in
1997, 74 prisoners were executed, about 2 percent of the roughly
3,400 on death row) is only twice the death rate from accidents
and violence for all American men, and only slightly greater than
the rate of accidental and violent death for all black males between
the ages of 15 and 34. "Based on these figures," they
wrote, "it is hard to believe that in modern America the
fear of execution would be a driving force in a rational criminal's
On the other hand, bad prison conditionswell known, pervasive
and immediateare likely to play a significant deterrent
role. "If I'm thinking about committing a crime," said
Levitt in an interview, "and I know what happens in prison,
and I know that there are lots of people with AIDS [there] that
are going to rape me, you know, if there's anything that could
deter me, that might be it."
The data bear out the hypotheses. Their study, forthcoming in
the American Law and Economics Review, analyzed state-level
data from 1950 to 1990, controlling for a variety of socioeconomic
variables, and found that prison conditions (as measured by rates
of prison death, mostly caused by illness) have a large and significant
impact on crime. "In terms of crimes reduced per prison death,
the estimated effects are quite large: 30-100 violent crimes and
a similar number of property crimes." The number of homicides
prevented is lower but still strong: 10 prison deaths are associated
with one to eight fewer murders.
In contrast, execution rates have only a small, statistically
insignificant effect on murder rates. "We find little systematic
evidence supporting a deterrent effect of capital punishment,"
wrote the authors. "There simply does not appear to be enough
information in the data on capital punishment to reliably estimate
a deterrent effect."
Though the authors make no reference to Beccaria's theory of crime
and punishment, their study seems an almost perfect confirmation
of it. The prospect of being sentenced to years of horrendous
prison life appears to be a strong deterrent to criminal activity.
As Beccaria described the potential criminal's internal monologue:
"If I commit such a crime, ... I shall be reduced to that
miserable condition for the rest of my life." Execution,
on the other hand, appears too unlikely, too abstract to be a
significant factor in the crime supply function. "The fear
of death," wrote Beccaria, "men always behold in distant
A second look
The second paper by Naci Mocan and Kaj Gittings, starts from the
same fundamental theory of deterrence. "Economists consider
criminal activity as a reaction to costs and incentives,"
said Mocan. "So the application of this framework to capital
punishment is just another test of whether the increased costs
or decreased costs of punishment are significant enough to impact
the reaction of individuals, and therefore the homicide rate."
In "Pardons, Executions and Homicide," Mocan and Gittings
look at homicide rates between 1977 and 1997, using regression
analysis to control for a variety of state characteristics like
age distribution, unemployment rate, racial composition and even
beer consumption. But the variables of principal interest to them
are the execution rate andin a novel innovationthe
rate of death row commutations. "According to economic theory,"
explained Mocan, "an increase in executions should send a
signal pertaining to an increase in the cost of crime, and an
increase in clemency or commutations is a signal indicating the
price of criminal activity is actually getting lower."
Again, the results turned out as the authors expected. "We
find that one extra execution reduces the homicides by five to
six," said Mocan. "And three extra commutations generate
one to one and a half extra homicides." The findings, said
the authors, are robust to variations in data sets, other variables
and mathematical transformations.
Mocan and Gittings also decided to simulate the earlier paper by
Katz, Levitt and Shustorovich. "It's an important paper, so
we tried to make sure that we were operating in the same framework,"
said Mocan. Among other things, they added prison deaths to their
initial equation to see if it had a significant impact. "We
tried hard to make these two papers as comparable as possible. But
in our framework, the prison deaths did not turn out to be significant
determinants. The execution rates and clemency rates turned out
to be more important."
So what does it mean?
The conflicting results are puzzling. Respected economists
with similar theories and methods arrive at opposite conclusions
about capital punishment. One possibility is simply that things
have changeda structural change in deterrence such that
executions didn't impact homicide during the time period Katz,
Levitt and Shustorovich examined (1950-1990) but did have an effect
in the more recent years (1977-1997) that Mocan and Gittings studied.
"Structural change is possible," said Mocan. "We
cannot rule out that there was a structural change in the way
that executions influence the homicide rate after the mid-1980s
or so." In future work, he plans to look at that possibility.
But "my gut feeling is that the reason [for different results]
is that there is more variation in the data in later years."
Indeed, Katz, Levitt and Shustorovich did find somewhat different
results in the first 20 years of their data than in the second
20. So it's possible that adding data from another seven years
during which executions rose and murders declined could bolster
the strength of the execution deterrent effect, while possibly
diminishing the effect of prison conditions.
Levitt, though, is skeptical. The number of executions is just
too low to expect it to have either a theoretical or statistical
impact of any real significance. Even if executions do have a
substantial effect, the annual number of executions is so low
and the variability in murder rates so wide from year to year,
that it is difficult to detect "the execution-related signal
from the noise in homicide rates."
"If all I knew were the coefficients you get from [1977 to
1997], the years Mocan looked at, then I'd say, yeah, it looks
like execution works," said Levitt. "But given that
we've got an earlier 40 years of experience where we don't see
much evidence that it works, and where there's a lot more variation,
I guess that would make me a lot more suspicious of drawing any
Gary Becker, a University of Chicago colleague of Levitt, points
out that policy measures can alter deterrence. "The disincentive
or deterrent effects through the death penalty will be higher
if prisons are made more comfortable ... because that means death
[would be] a much worse alternative to imprisonment," he
noted, commenting on this Region article. "On the
other hand, it's hard to believe that death penalty [deterrence]
can be very high under present conditions, when few get it, it's
often very delayed and its imposition is highly uncertain."
But under different conditions of penalty imposition and prison
treatment, capital punishment deterrence could be greater, he
noted. "These are political and public policy issues one
has to resolve."
Both Levitt and Mocan emphasize that it is not their desire to
campaign for or against the death penalty. "The economist's
contribution," said Mocan, "is just to provide a piece
of objective evidence on whether or not there's a deterrent effect,
and how big it is, without taking a position whether it is good
or bad." But they recognize that their results will inevitably
be used or dismissed by advocates of one position or the other.
Still, they take pains to stress other considerations. Katz, Levitt
and Shustorovich caution against drawing policy prescriptions
from their results on prison conditions. While the effect on crime
of prison deaths is strong in one sense, the elasticities imply
that a doubling of the prison death rate would reduce the crime
rate by just a few percentage points. "Given the limited
efficiency gains implied by these estimates, the moral and ethical
considerations surrounding these issues would appear to dominate
any economic arguments," they concluded.
And Mocan points out that even if the death penalty is a very
strong deterrent, "that still doesn't mean that one needs
to support it, because there [are many other] ethical and religious
considerations that need to be taken into account." Mocan
added that much recent research has found substantial flaws in
the application of the death penalty, including incompetent legal
counsel, racial disparities and unfair discretion in commutations.
The focus of public debate on the issue has begun to shift, said
a recent Economist editorial, "from the question of
whether the death penalty is right in theory to whether it is
fair in practice."
That question hasn't gone unnoticed by the Supreme Court. "Serious
questions are being raised about whether the death penalty is being
fairly administered in this country," said Justice Sandra Day
O'Connor last July. "If statistics are any indication, the
system may well be allowing some innocent defendants to be executed."
O'Connor noted that over 90 inmates have been exonerated and set
free since 1973.
Is deterrence what we seek?
It may well be that the American publicand their policymakerssee
capital punishment as a means to ends other than crime deterrence. Over
the last 25 years, the gap between those who believe in the death penalty
and those who believe it has a deterrent effect has grown ever wider,
according to public opinion polls by Harris Interactive. Sixty-seven percent
of Americans surveyed in July 2001 said they believe in the death penaltyidentical
to the fraction that felt that way in 1976but belief in its deterrent
effect has slipped from 59 percent to 42 percent during that same quarter
century (see chart).
Banner, the death penalty historian, reports that surveys conducted between
1983 and 1991 indicated that a large majority of death penalty supporters
would still favor it even if it had no effect at all on the murder rate.
And he suggests that the death penalty has come to serve two other goals
for Americans: retribution and collective expression of condemnation.
"It is this expressive quality that best accounts for the renewed
popularity of capital punishment at the end of the twentieth century."
Or as Frank Keating, the governor of Oklahoma, said last year, "Capital
punishment is a statement of moral outrage and justice sought and restored."
Beccaria would not have approved. In his mind, the purpose of punishment
was not vengeance or venting, but prevention and deterrence. "The
intent of punishments is not to torment a sensible being, nor to undo
a crime already committed," he wrote. "The end of punishment
is no other than to prevent the criminal from doing further injury to
society and to prevent others from committing the like offence."
But whether Beccaria was right about the minimal deterrence of capital
punishment, we may never know. The best efforts of economists over the
last quarter century have been nothing if not inconclusive. Theory itself
provides no definitive guidance. "I don't think the economic approach
to crime requires or necessarily implies that the death penalty itself
has a big deterrent effect," said Becker. "It doesn't rule it
out, but it doesn't imply it."
And it seems unlikely that empirical analysis will soon settle the question.
Indeed, a draft paper released early this year by economists at Emory
University says the deterrent effect of capital punishment is at least
three times stronger than the Mocan-Gittings estimate. The latter study,
intimate the Emory economists, has "econometric problems."
"What's interesting about this is that it mirrors so closely the
Ehrlich debate of the '70s," said Chicago's Levitt, "which basically
all came down to if you tweak his specification at all, you get numbers
that are totally different." And reaching a definitive answer about
deterrence could well be impossible since current execution rates may
be too low to provide sufficient empirical data. "I really think
not that the answer is 'yes' or 'no,'" said Levitt, "but that
there's not enough information to figure it out. There may never be enough.
It may just be a question that can't be answered."