Deterrent Effect Of Capital Punishment Research Articles

Uses and Abuses of Empirical Evidence in the Death Penalty Debate

Does the death penalty save lives? A surge of recent interest in this question has yielded a series of papers that purport to show robust and precise estimates of a substantial deterrent effect of capital punishment. We assess the various approaches that have been used in this literature, testing the robustness of these inferences. Specifically, we start by assessing the time series evidence, comparing the history of executions and homicides in the United States and Canada, and within the United States, between executing and non-executing states. We analyze the effects of the judicial experiments provided by the 1972 Furman and 1976 Gregg decisions and assess the relationship between execution and homicide rates in state panel data since 1934. We then revisit the existing instrumental variables approaches and assess two recent state-specific execution moratoria. In each case, we find that previous inferences of large deterrent effects based upon specific samples, functional forms, control variables, comparison groups, or IV strategies are extremely fragile and that even small changes in specifications yield dramatically different results. The fundamental difficulty facing the econometrician is that the death penalty - at least as it has been implemented in the United States - is applied so rarely that the number of homicides that it can plausibly have caused or deterred cannot be reliably disentangled from the large year-to-year changes in the homicide rate caused by other factors. As such, short samples and particular specifications may yield large but spurious correlations. We conclude that existing estimates appear to reflect a small and unrepresentative sample of the estimates that arise from alternative approaches. Sampling from the broader universe of plausible approaches suggests not just reasonable doubt about whether there is any deterrent effect of the death penalty, but profound uncertainty - even about its sign.

THE DEATH PENALTY MEETS SOCIAL SCIENCE: Deterrence and Jury Behavior Under New Scrutiny

▪ Abstract Social science has long played a role in examining the efficacy and fairness of the death penalty. Empirical studies of the deterrent effect of capital punishment were cited by the Supreme Court in its landmark cases in the 1970s; most notable was the 1975 Isaac Ehrlich study, which used multivariate regression analysis and purported to show a significant marginal deterrent effect over life imprisonment, but which was soon roundly criticized for methodological flaws. Decades later, new econometric studies have emerged, using panel data techniques, that report striking findings of marginal deterrence, even up to 18 lives saved per execution. Yet the cycle of debate continues, as these new studies face criticism for omitting key potential variables and for the potential distorting effect of one anomalously high-executing state (Texas). Meanwhile, other empiricists, relying mainly on survey questionnaires, have taken a fresh look at the human dynamics of death penalty trials, especially the attitudes and personal background factors that influence capital jurors.

State Executions, Deterrence, and the Incidence of Murder

This study employs a panel of U.S. state-level data over the years 1978–1997 to estimate the deterrent effect of capital punishment. Particular attention is paid to problems of endogeneity bias arising from the non-random assignment of death penalty laws across states and a simultaneous relationship between murders and the deterrence probabilities. The primary innovation of the analysis lies in the estimation of a simultaneous equations system whose identification is based upon the employment of instrumental variables motivated by the theory of public choice. The estimation results suggest that structural estimates of the deterrent effect of capital punishment are likely to be downward biased due to the influence of simultaneity. Correcting for simultaneity, the estimates imply that a state execution deters approximately fourteen murders per year on average. Finally, the results also suggest that the announcement effect of capital punishment, as opposed to the existence of a death penalty provision, is the mechanism actually driving the deterrent effect associated with state executions.

Getting off Death Row: Commuted Sentences and the Deterrent Effect of Capital Punishment

This paper merges a state‐level panel data set that includes crime and deterrence measures and state characteristics with information on all death sentences handed out in the United States between 1977 and 1997. Because the exact month and year of each execution and removal from death row can be identified, they are matched with state‐level criminal activity in the relevant time frame. Controlling for a variety of state characteristics, the paper investigates the impact of the execution rate, commutation and removal rates, homicide arrest rate, sentencing rate, imprisonment rate, and prison death rate on the rate of homicide. The results show that each additional execution decreases homicides by about five, and each additional commutation increases homicides by the same amount, while an additional removal from death row generates one additional murder. Executions, commutations, and removals have no impact on robberies, burglaries, assaults, or motor‐vehicle thefts.

Prison Conditions, Capital Punishment, and Deterrence

Previous research has attempted to identify a deterrent effect of capital punishment. We argue that the quality of life in prison is likely to have a greater impact on criminal behavior than the death penalty. Using state-level panel data covering the period 1950-90, we demonstrate that the death rate among prisoners (the best available proxy for prison conditions) is negatively correlated with crime rates, consistent with deterrence. This finding is shown to be quite robust. In contrast, there is little systematic evidence that the execution rate influences crime rates in this time period.

Does Capital Punishment Have a Deterrent Effect? New Evidence from Postmoratorium Panel Data

Evidence on the deterrent effect of capital punishment is important for many states that are currently reconsidering their position on the issue. We examine the deterrent hypothesis by using county-level, postmoratorium panel data and a system of simultaneous equations. The procedure we employ overcomes common aggregation problems, eliminates the bias arising from unobserved heterogeneity, and provides evidence relevant for current conditions. Our results suggest that capital punishment has a strong deterrent effect; each execution results, on average, in eighteen fewer murders—with a margin of error of plus or minus ten. Tests show that results are not driven by tougher sentencing laws and are robust to many alternative specifications.

State Executions, Deterrence, and the Incidence of Murder

This study employs a panel of state data over the years 1978-1997 to estimate the deterrent effect of the probability of apprehension, the probability of conviction given apprehension, and the probability of execution given conviction on the rate of per-capita murders. Particular attention is paid to problems of endogeneity bias arising from the non-random assignment of death penalty laws across states and a simultaneous relationship between murders and the deterrence probabilities. The primary innovation of the analysis lies in the estimation of a simultaneous equations system whose identification is based upon the employment of instrumental variables motivated by the theory of public choice as it relates to the criminal justice system and bureaucratic behavior. This is the first time such instruments have been used in the literature, and it is shown that these instruments are both statistically relevant and valid. The estimation results suggest that structural estimates of the deterrent effect of capital punishment are likely to be downward biased due to the influence of simultaneity. Correcting for simultaneity, the estimates imply that a state execution deters approximately fourteen murders per year on average.

The Deterrent Effect of Capital Punishment: Evidence from a 'Judicial Experiment'

Does capital punishment deter capital crimes? We use panel data covering the fifty states duringthe period 1960-2000 period to examine the issue. Our study is novel in four ways. First, we estimate the moratorium's full effect by using both pre- and postmoratorium evidence. Second, we exploit the moratorium as a judicial experiment to measure criminals' responsiveness to the severity of punishment; we compare murder rates immediately before and after changes in states' death penalty laws. The inference draws on the variations in the timing and duration of the moratorium across states provide a cross section of murder rate changes occurring in various time periods. Third, we supplement the before-and-after comparisons with regression analysis that disentangles the impact of the moratorium itself on murder from the effect on murder of actual executions. By using two different approaches, we avoid many of the modeling criticisms of earlier studies. Fourth, in addition to estimating 84 distinct regression models - with variations in regressors, estimation method, and functional form - our robustness checks examine the moratorium's impact on crimes that are not punishable by death. Our results indicate that capital punishment has a deterrent effect, and the moratorium and executions deter murders in distinct ways. This evidence is corroborated by both the before-and-after comparisons and regression analysis. We also confirm that the moratorium and executions do not cause similar changes in non-capital crimes. The results are highly robust.

Does Capital Punishment Have a Deterrent Effect? New Evidence from Post-moratorium Panel Data

Evidence on the deterrent effect of capital punishment is important for many states that are currently reconsidering their position on the issue. We examine the deterrent hypothesis using county-level, post-moratorium panel data and a system of simultaneous equations. The procedure we employ overcomes common aggregation problems, eliminates the bias arising from unobserved heterogeneity, and provides evidence relevant for current conditions. Our results suggest that capital punishment has a strong deterrent effect; each execution results, on average, in 18 fewer murders%97with a margin of error of plus or minus 10. Tests show that results are not driven by tougher sentencing laws, and are also robust to many alternative specifications.

Capital punishment in Poland: The debate continues1

Throughout its modern history, Poland has not escaped controversies surrounding the use of the death penalty. Tracing the historical development of laws dealing with the issue demonstrates an evolution influenced by various legal, political, social, philosophical, and international factors, leading up to the current absence of the penalty from the Polish legal system. The debate in society revolves around some stereotypical views held by different social groups. One of the biggest challenges is how to reconcile those views with empirical evidence, especially on issues like the deterrent effect of capital punishment. The authors describe the death penalty debate in Poland from these perspectives and take a retentionist position with regard to some selected crimes. As long as there are individuals willing to take other people's lives in a premeditated and deliberate manner demonstrating callous contempt for another person's existence, death remains the only punishment satisfying a sense of social justice and upholding the value of human life.

Sensitivity Analyses Of The Deterrence Hypothesis: Let's Keep The Econ In Econometrics

Leamer presents a scathing critique of classical sensitivity analysis concerning regression specification. The argument is that the classical approach lacks a systematic way to determine what explanatory variables truly belong in the regression when there is uncertainty about proper model specification. The remedy offered is Extreme Bound Analysis (EBA). Leamer illustrates the merits of EBA by applying it to a study of the deterrent effect of capital punishment. EBA aims to determine the sensitivity of estimated effects of one or more variables of primary interest in a regression equation to the inclusion of additional regressors. It purports to solve the problem by allowing a researcher to partition a set of explanatory variables into important and subsets. Only the former is included in the regression with no restrictions. Linear combinations of variables' coefficients, in contrast, are constrained to match the researcher's prior beliefs -- generally zero. EBA produces the largest and smallest estimated coefficients of the focus variables (which themselves could be dubbed either doubtful or important), based on these restrictions. If the computed extreme bounds are too wide, or span zero, the effects of the focus variables are declared too fragile to warrant credibility. Leamer's application of EBA to capital punishment is based on a study of murder rates across US states in 1950 conducted by McManus, and later published by him as a separate paper. Both authors argue that EBA casts serious doubt on the validity of the deterrence hypothesis, at least as it pertains to capital punishment. They conclude that the evidence on deterrence is essentially a product of the researcher's prior beliefs. Bleeding hearts could legitimately infer the absence of deterrence, while believers in eye-for-an-eye would reject as effective any penalty other than death. Rational economists are no more correct in inferring that offenders respond to incentives than are some criminologists who view crime merely as a product of social and environmental ills. If true, this amounts to an impressive testimony about both the power of EBA and the validity of the economic approach to crime. We suppose that partly for this reason Leamer has titled his paper (supra note 1) grandiloquently Let's take the out of econometrics. In this paper we suggest that the best way to keep the out of econometrics is to keep economics in it. In section 1 we examine the merits of EBA as a replacement for the classical approach. We find the promised remedy worse than the problem it is alleged to cure. The main methodological shortcomings of EBA have already been pointed out by McAleer, Pagan, and Volker [MPV]. Apparently, however, the latter's critique has escaped many economists, perhaps because it has not been backed up by convincing empirical evidence. In section 2 we use three data sets concerning consumption, production, and human capital investment to show how EBA, as applied by Leamer and McManus [LMC], would find basic economic theory to be fragile. It could dismiss laws of demand, production, and investment as a con job, however, not because of any faults in the theory, but because of the inherent flaws of EBA itself. These flaws are also shown to be responsible for LMC's premature inferences about the validity of the deterrence hypothesis. Since LMC's analysis of deterrence is shown to be based on a faulty methodology, we feel an obligation not just to correct the impression their work has left about the strength of the underlying economic model, but also to offer an alternative sensitivity analysis using classical techniques. In section 3 we use similar cross-state data on the incidence of murder as well as other related crimes from both 1940 and 1950 to address a number of potential biases in estimates of supply-of-offenses functions in light of the underlying theory. We focus on 1940 and 1950 not just because LMC used 1950 data, but also because these are the most recent years in which a majority of states in the US still applied capital punishment at considerable annual frequencies. Our analysis does not necessarily settle the issue. We do show, however, that LMC's analysis does not raise legitimate doubts about empirical results supporting deterrence, let alone prove that these results are just a product of researchers' prior beliefs. More generally, our work indicates that EBA's basic defect is that it does not put any weight on theory as the critical guideline for conducting sensitivity analysis. Indeed, when we conduct a theory-based sensitivity analysis using our cross-state data, we find additional support for the deterrence hypothesis.

Capital punishment and deterrence: a comment on Cloninger's paper

Cloninger (1992) applied the portfolio approach to criminal behaviour and illustrated the deterrent effect of capital punishment by use of data from 1983–1988 across the states of America and the District of Columbia. This comment suggests two possible flaws in Cloninger's analyses, which, if taken into account, may shed more light on the effect which he purports to demonstrate and it suggests that application of the analyses to an earlier historical period may be necessary.

Capital Punishment and the Deterrence of Violent Crime in Comparable Counties

A matching process identified 293 pairs of counties in the United States that share 45 percent or more of their borders across a state line. Data from the 1988 County and City Data Book were then used to examine social, demographic, and economic differences within these matched pairs, with the difference in the violent crime rate in each pair employed as the dependent variable. Three variables reflecting the existence and use of capital punishment in the two states represented in each matched pair-the existence of a provision for capital punishment, the number of people executed since 1976, and the number of people currently held on death row-were then entered in the analysis to examine the effects of capital punishment. The capital punishment variables did not account for any significant portion of the differences in the violent crime rates, and, contrary to deterrence theory, what effects these variables did have were positive. These findings support the large number of studies at state and national levels that have found no deterrent effect of capital punishment.

The attitude polarization phenomenon: Role of response measure, attitude extremity, and behavioral consequences of reported attitude change.

Four studies examined the generality of attitude polarization (C. G. Lord, L. Ross, & M. R. Lepper, 1979). Biased assimilation of essays on 2 controversial issues was substantial and correlated with reported attitude change. Polarization was observed for reported attitude change on capital punishment and generally stronger in Ss with extreme than moderate attitudes. Polarization was not indicated in a pre-post measurement design. For affirmative action, reported polarization was not observed. The hypothesis that Ss reporting polarization would subsequently write particularly strong essays was not supported, although those reporting depolarization wrote relatively weak essays. The results suggest the relevance of individual differences in reported attitude change but do not confirm the powerful inferences frequently drawn regarding the pervasive, undesirable consequences of self-reported attitude polarization. An influential, frequently cited experiment in the social cognition literature is that by Lord, Ross, and Lepper (1979). In this study, proponents and opponents of capital punishment were shown an identical set of alleged research findings containing evidence both in favor of and against capital punishment. Two important phenomena were observed. First, subjects evaluated more positively the research that agreed with their preexisting position, a result termed biased assimilation. Thus, subjects who were in favor of capital punishment rated method Xzs superior method Y if the former yielded support for the deterrent effect of capital punishment, but rated the identical method as inferior if it refuted the efficacy of capital punishment. The converse was true for subjects opposed capital punishment. The second, particularly intriguing finding was that subjects reported that their attitudes had become more extreme in the direction of their initial point of view after evaluating the research evidence, an effect termed attitude polarization. Thus, showing proponents and opponents of capital punishment an identical body of mixed evidence appeared to increase further the gap between their views (Lord et al, 1979, p. 2105). Lord et al. (1979) suggested that in the subjects' biased processing of the research information, they had emerged with an inflated sense of the amount of evidence supporting their initial belief. Correlational analyses involving the relative degree of biased assimilation and the magnitude of reported attitude change (polarization) supported this account. That subjects gave substantially higher evaluations research that supported

Modelling in econometrics: The deterrent effect of capital punishment

Modelling in econometrics: The deterrent effect of capital punishment

The Deterrent Effect of Capital Punishment in the Five Most Active Execution States: A Time Series Analysis

This study examines the effect of the death penalty on the murder rate. A 50-year time series is employed for the period 1930-1980 for the five states with the largest number of executions during this period: Georgia, New York, Texas, California, and North Carolina. Taken together, these five states accounted for 40 percent of all the executions performed during this period. Incorporating a lag structure for the effect of executions, as well as several theoretically relevant explanatory variables for homicides, the study identifies no deterrent effect for executions. Several different policy-relevant analyses are performed, all with the same result. Neither the existence of the death penalty, its imposition, nor the level of imposition explains significant amounts of the variation in homicide rates in the 50-year period, 1930 to 1980.

The Deterrent Effect of Capital Punishment: An Analysis of Daily Homicide Counts

Abstract This article analyzes daily homicide data to address whether the occurrence of executions exerts a short-term deterrent effect. The data analyzed are drawn from computerized death certificates from California during the early 1960s, the last period during which frequent executions were carried out there. The analysis of data from one legal jurisdiction helps overcome criticisms of earlier studies based on data aggregated over executing and nonexecuting jurisdictions. Furthermore, the detailed information in the death certificates allows one to analyze the murders of victims of different race and sex separately, which in principle should allow one to detect possible race- or gender-specific effects too small to be discerned in aggregate data. Poisson and compound-Poisson regression models are estimated, to control for seasonal fluctuations and to measure the effect of executions on daily homicide counts. Two-week and four-week periods surrounding the dates on which executions took place are examin...

The Deterrent Effect of Capital Punishment: An Analysis of Daily Homicide Counts

Abstract This article analyzes daily homicide data to address whether the occurrence of executions exerts a short-term deterrent effect. The data analyzed are drawn from computerized death certificates from California during the early 1960s, the last period during which frequent executions were carried out there. The analysis of data from one legal jurisdiction helps overcome criticisms of earlier studies based on data aggregated over executing and nonexecuting jurisdictions. Furthermore, the detailed information in the death certificates allows one to analyze the murders of victims of different race and sex separately, which in principle should allow one to detect possible race- or gender-specific effects too small to be discerned in aggregate data. Poisson and compound-Poisson regression models are estimated, to control for seasonal fluctuations and to measure the effect of executions on daily homicide counts. Two-week and four-week periods surrounding the dates on which executions took place are examin...

Capital punishment and the deterrent effect revisited: Recent time-series econometric evidence

This article theoretically develops and empirically tests the relationship between criminal homicide crime rates in the United States for the period 1965–1985 and the deterrent effect of capital punishment by utilizing a recursive system of equations method. The analysis reveals that not only does a deterrent effect of capital punishment exist but also that changes in commonly selected law enforcement, judicial, demographic, and economic control variables are significant in a manner consistent with implications from general theoretical models of criminal behavior and within frameworks specifically dealing with murder and nonnegligent manslaughter.

How Fragile are Fragile Inferences? A Re-Evaluation of the Deterrent Effect of Capital Punishment

Extreme bounds analysis attempts to measure the effects of the uncertainty in the specification of the explanatory variables in a regression model on the estimated coefficients of interest. Standard errors for the stochastic extreme bounds are computed using the bootstrap technique. State-by-state cross section data are used to study the deterrent effect of capital punishment in the United States in 1950. The bootstrap standard errors are sufficiently large for some bounds to suggest caution in the interpretation of the empirical results regarding the fragility of inferences for the deterrent effect of capital punishment. Copyright 1989 by MIT Press.