«School of Economics and Political Science, University of St. Gallen Department of Economics Editor: Martina Flockerzi University of St. Gallen School ...»
1990. He presents strong evidence for a brutalisation but at best rather weak evidence for a deterrence effect.
32. See also E. COHEN-COLE, J. FAGEN and S. DURLAUF (2009, p. 335) who average the models of H. DEZHBAKHSH, P. RUBIN and J.M. SHEPHERD (2003) with the one of J.J. DONOHUE and J. WOLFERS (2005) and reach the conclusion that “evidence of deterrent effects appears, while not inexistent, weak.”
33. See, for example, G.S. BECKER (2006, p. 1): “I support the use of capital punishment because, and only because, I believe it deters murders. … The available data are quite limited, however, so one should not base any conclusion solely on the econometric evidence. Still, I believe the preponderance of evidence does indicate that capital punishment deters, … Of course, public policy on punishments cannot wait until the evidence is perfect. Even with the limited quantitative evidence available, there are good reasons to believe that capital punishment deters murder. Most people, and murders in particular, fear death, especially when it follows swiftly and with considerable certainty following the commission of a murder.” See also P.H.
RUBIN (2009) who makes it very clear that there has to be a deterrent effect of the death penalty whatever econometric analyses show.
– 19 – penalty to be unconstitutional point to the weaknesses of these studies.34) As the examples of J. FAGAN (2005) and J. SHEPHERD (2004a) show, this can lead to contradictory statements in testimonies before parliamentary (and other) committees.
 That social scientists contradict each other in such situations is neither new nor unique:
there are numerous other such examples.35) What is more or less unique is the divide between economics and the other social sciences: While most (not all) economists believe in the deterrent effect of death penalty and defend the evidence presented, most other social scientists, including law professors, question the evidence and do not believe that it can justify death penalty. Moreover, this debate might be more heated than other ones, but, taking into account the issue at stake, “a question of live and death”, to cite I. EHRLICH (1975), this is not at all astonishing.
 The divide between the social sciences is also not surprising. Economists believe in incentives more than other social scientists do.36) They usually believe in the deterrent effect of punishment and, therefore, also of capital punishment. The only relevant question for them is whether the change from life imprisonment to death penalty has a positive marginal deterrence effect. In recent decades, the deterrent effect of criminal law has been questioned by psychologists and by people from law departments following them; besides deterrence, there are many other reasons why people obey the law.37) Consequently, the marginal deterrence effect of death penalty has been questioned, too. This does not necessarily imply that there is no deterrent effect at all. But whether the marginal effect is significant and large enough to justify legislation is still a question to be discussed.
 In recent years, economists learned to take the results of psychologists more seriously, developing the new approach of ‘behavioural economics’.38) There, the effect of deterrence is highly questioned as well. Moreover, they learned that in many situations people do not act rationally, at least not according to conventional standards of rationality. This holds for murderers, too. But, as R.H. MCADAMS and T.S. ULEN (2009) correctly argue, for deterrence to become effective it is sufficient that those who might, but actually do not commit murders are deterred. Moreover, even though the reaction of individuals is in many situations weak, beSee, for example, J. FAGAN (2005, p. 2): “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 outliers and years, weak to non-existent tests of concurrent effects of incarceration, statistical confounding of murder rates with death sentences, failure to consider the general performance of the criminal justice system, 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, responding to counterfactual claims, and basic comparison with other scenarios. Some simple examples and contrasts, including the careful analysis of the experience in Massachusetts compared to other states, lead to a rejection of the idea that either death sentences or executions deter murder.”
35. See, for example, G. KIRCHGÄSSNER (2005) with respect to environmental policy or G. KIRCHGÄSSNER (2007) with respect to natural damage insurance in Switzerland.
36. See for this, for example, G. KIRCHGÄSSNER (2005a).
37. See, for example, K.-D. OPP (1989), T.R. TYLOR (1990, 1997), P.H. ROBINSON and J.M. DARLEY (2004) or A.M. LICHT (2008).
38. See, for example, N. GAROUPA (2003) or R.H. MCADAMS and T.S. ULEN (2009).
– 20 – havioural economists do not reject the notion that sufficiently strong incentives have an impact on human behaviour. Thus, the question at stake here is ‘only’ whether the marginal effect of a change from lifelong imprisonment to death penalty is a strong enough incentive, generally and in particular given today’s situation in the United States.
 Because of the contradictory evidence that is available there will be no consensus about this question, at least not in the near future. The same (as well as other) people will present similar evidence as before, with ever improved statistical techniques. There is some hope that these improved techniques will lead to some convergence of the results, not only of the methods, but there is a high probability that this hope which has been frustrated over the last thirty years will also be frustrated in the (near) future. There are too many possibilities for different specifications which can be justified with arguments of plausibility to expect a full convergence. Selective perceptions will again have the effect that researchers believe in those results that seem to be plausible from their a priori point of view.
 This perception of the scientific process might seem to be rather pessimistic. It is, however, only realistic. It is partly due to the fact that this is an area where we cannot perform controlled experiments, and the quasi-natural experiments which are sometimes unintentionally conducted by political authorities also do not give clear answers, as the recent history of the United States, (and the papers analysing these experiments) show. This is not specific for economics and the other social sciences as one might think, because, as K.R. POPPER (1962, p.
95) writes: “It is a mistake to assume that the objectivity of a science depends on the objectivity of the scientist. And it is a mistake to believe that the attitude of the natural scientist is more objective than that of the social scientist.... [T]he objectivity of science is not a matter of the individual scientists but rather the social result of their mutual criticisms, of the friendly-hostile division of labour among scientists, of their co-operation and also of their competition.”  This mutual criticism is the driving force of scientific progress, and it allows ‘bad research’, theoretical as well as empirical, to be discredited. Thus, ideology or, in other words, the personal convictions of the researchers will nearly always play a role, but competition and open discussion can (and hopefully will) have the effect that the majority opinion in the scientific community goes into the correct direction in the long-run, even if not all members of this community will be convinced. M. PLANCK (1933, p. 299) already wrote with respect to scientific progress: “An important scientific innovation rarely makes its way gradually winning over and converting its opponents: it rarely happens that Saul becomes Paul. What does happen is that its opponents gradually die out and that the growing generation is familiarized with the idea from the beginning.” This holds generally, for all sciences, but for the issue at stake, the discussion about the potential deterrence effect of capital punishment, in particular. Given the demands for the precision of scientific advice that are often expressed, this does not seem to be very much, but more cannot be expected in a realistic perspective. Moreover, this does not imply that policy advice is useless, but if competing experts are asked, it is hardly the case that advice is unanimous. Thus, policy advice can clarify facts, and this holds also for econometric estimates of the deterrence effect of capital punishment, but ideology will always also play a role.
– 21 –  Besides the disputed facts there is, however, a moral question with respect to capital punishment as well, which has also been raised again recently. If, (but only if) capital punishment deters, the question of its moral justification or rejection becomes more complicated.
Based on a strong belief in the deterrent effect of the death penalty, C.R. SUNSTEIN and A.
VERMEULE (2005) defend the position that capital punishment might not only be morally acceptable but even be morally required. The basis of their argument is the proposition that the difference between act and omissions is, for the government as a moral actor, misleading in this case (and in other situations as well). The usual example of a ‘tragic decision’ is whether it is allowed or even morally obliged to kill an innocent person in order to save the lives of several other people. Despite the fact that consequentialism might demand this, it contradicts our usual moral intuitions, because it is not allowed to do any harm to an innocent person. A murderer is definitely not an innocent person. One might question whether deliberate killing of a human person can be morally justified at all, aside from situations of (personal) selfdefence or whether it should, like torture, be negated categorically. If the latter holds, there is no possibility to justify the death penalty. Executing murderers might, however, be seen as a societal self-defence if it really prevents further murders. Then, the problem arises that sometimes innocent people are executed. We do, however, neither know those people who are innocent and, due to judicial errors, are executed, nor those whose lives are saved due to the deterrence effect of the death penalty. Thus, we face a new variant of the act-versus-omission problem.
 Given this situation, C.R. SUNSTEIN and A. VERMEULE (2005) question the distinction between acts and omissions in this context (and also in the more general context of public policy altogether) and argue in favour of the death penalty because we have to compare on both sides ‘statistical lives’, and it saves more lives than it risks. C.S. STREIKER (2005) argues against this position from a deontological point of view because “executions constitute a distinctive moral wrong, (purposeful as opposed to non-purposeful killing) and a distinctive kind of injustice (unjustified punishment).”39) In their reply, C.R. SUNSTEIN and A. VERMEULE (2005a) reject this by restating the argument that innocent people are involved on both sides, that deterrence should play a major role in moral judgements, and “if capital punishment has significant deterrent effects, then the moral argument for the ultimate penalty is greatly strengthened – even, we think, to the point of raising the possibility that capital punishment may be morally required” (p. 857).40)  Even if one does not follow this conclusion, one can hardly reject the notion that deterrence should play a major role in legal judgements and, because legal judgments should be morally justified, also in moral judgements. Thus, the debate about the possible deterrent efAnother interesting aspect raised by her but which cannot be discussed here is that giving up the distinction between act and omission with respect to governmental policies would lead to far more extensive government interventions than we experience today.