Cómo debemos comunicarnos?

The third implication from Becker’s theory of crime, the possibility of deterrence, is a long debated idea. Since the potential criminals are assumed to respond rationally to a change in the return from crime, crime rates could be reduced using an aggravation of the potential punishment and/or a higher probability to be caught (Cook et al. 2013), according to the theory. Deterrence has two dimensions, first, the probability of getting punished and secondly the severity of the punishment. The severity of the punishment is mainly determined by the legal system and the jurisdiction, whereas the probability of the punishment is determined by the efficiency of the legal system and the police force.

In Mexico, the legal system has its roots in the Colonial law of the 16th _{century but was} reformed by the 1917 constitution which was the main source of Mexican law for the remaining of the 20th century (Reynolds 1970). The Judicial Power is vested in the Supreme Court, but every state has its own state supreme court that applies the state laws. On the state level, there are also courts of first instance which are the ones dealing with cases of the “common law” (fuero común), the kind of offenses that only affect the victim of the act directly, such as robbery, theft, rape, bodily injury and most importantly homicide (Procuraduría General de la República 2011).

One proxy that can gauge the severity of the punishment and has been used in previous studies is the death penalty, since it is “assumed to be an indicator of the overall severity of [the] legislation regarding the punishment of offenders” (Fajnzylber et al. 2000, p. 249). If the death penalty has a deterrent effect is however widely debated. Ehrlich (1975) for example shows that the death penalty has a major impact on crime rates, while others found no evidence for deterrence (Donohue and Wolfers 2006, Mathieson and Passell 1976, Levitt 1995a and 1997).

between 1924 (Michoacán) and 1975 (Sonora) (Gonzalez Mariscal 2011). This variation can be used to examine if the abolition of the death penalty had an impact on homicide rates. One problem with measures of severity of the punishment is that they might suffer from endogeneity, since the severity of the punishment can react to the development of the country’s crime rate. Countries with higher crime rates also tend to have tougher legislation, whereas states with low crime rates might abolish the death penalty first. Hence, observing a positive coefficient of the death penalty might be caused by endogeneity.

The second dimension of the deterrence apart from the severity of the punishment is the probability of receiving the intended punishment after committing a crime. Even the most severe punishment will not have any deterrent effect if it is not enforced. Proxies that capture the probability of getting punished are for example indicators of efficiency of the police force and the jurisdiction system, such as the clear-up rate. In Mexico, the probability of punishment seems to be unbelievably low: Per Cascante (2013), around 98.2% of all killings went unpunished in 2012.

The newly assembled data set contains information about the number of persons accused of homicide as well as the number of convictions for homicide. Figure B.16 compares the development of these to the homicide rate, each indicator measured as rate per 100,000. In 1940, the first year for which all three variables are available, a big gap between the number of homicides, the number of persons accused and the number of persons convicted is noticeable. There are more than 60 homicides per 100,000 inhabitants, however there were only around 33 persons accused of homicide and only 14 convicted. This translates in a probability of punishment of only around 23%. The clear majority of murderers never had to face punishment. Over the course of the century, the three rates converged significantly, reaching almost the same level in the 1970s (17 homicides and 12 sentenced) and hence a clear-up rate of 70%. While homicide rates remained stable in the 1970s and 1980s, the number of people accused and

sentenced continues to decrease. This insinuates that these additional murderers successfully evaded punishment. It is possible that the violence emerging in these decades was mainly drug related, hence inflicted by illegal organizations that were successfully evading apprehension, mainly through corruption. Due to this impunity, the gap between the number of homicides and people convicted for murder widened again until 1988 (17 homicides vs. 7 sentenced), reaching again a lower clear-up rate of only 40%, however this value is still far away from the abovementioned clear-up rate of only 1.8% in 2012.

The presence of widespread impunity weakens the public trust in legal institutions and consequently their deterrent ability. Owens (2013) shows that the main impact of police on crime is through deterrence and not through the actual detention of criminals. If the probability of punishment is very low however, then the police force loses this deterrent function, which might be the case in Mexico. Hence it is not clear, if it is possible to find a deterrent effect of the legal institutions or the death penalty. The empirical analysis will show, if any of the two dimensions of the deterrent effect, the severity of the punishment as well as the probability of receiving the punishment, did significantly reduce the homicide rate in 20th century Mexico.

Since the 1960s, the results of numerous studies have supported Becker’s theory and shown that crime is indeed determined by the economic conditions such as income levels, education, inequality and deterrent factors, and probably not as much by the individual’s character (for example Cook and Laub 1998; Eide, Rubin, Shepherd 2006; Dezhbakhsh et al. 2003). These mechanisms have been proven especially in the field of property crimes. In the field of violent crime however, especially for severe crimes like rape, homicide and hate crimes, the “rational choice theory” is sometimes not sufficient to explain crime incidence. Sociological theories offer some additional insights using more a wider range of potential influence factors.