It takes more than a motivated offender to create a criminal act. A burglar needs an accessible home and no interference from a watchful neighbour. A car thief needs a vehicle that can be moved inconspicuously. A violent offender needs a suitable counter party.
The basic insight that crime is interactive in nature has profound implications for both the analysis of crime and the conduct of crime policy. Even though the above may seem too trivial to mention, much research into crime ignores the fact that crime is not determined by the preferences of the offender alone. Crime is not just the result of an upbringing that went wrong or an unfinished school degree. A potential offender acts under constraints, including familiarity with suitable targets and the perceived risk of detection and its consequences. These constraints are amenable to government intervention. This is a well-known fact in the area of law enforcement, with many studies providing evidence for deterrence and incapacitation effects, but it is not so well known in the area of victim precaution. In this column, we present rare evidence on the impact of a policy targeted at strengthening the victim response to the crime risk.
The importance of constraints in the here and now
As Isaac Ehrlich and Philip Cook pointed out in the 1980s, limiting the study of crime to offenders is like studying markets with only supply and no demand (Ehrlich 1981, Cook 1986). The issue is not that preferences of offenders do not matter, of course they do, but that an exclusive focus on the offender ignores the interactive nature of crime. Only in debates about gun control does the active role of victims still receive some attention, leaving aside all other less controversial protective measures such as keeping valuables out of sight, avoiding certain streets, locking doors, and driving rather than walking at certain times of the day.
One basic fact that suggests the importance of constraints in the here and now is the great variation in the crime rate. Within a decade, the crime rate can double, as evidenced in the 1960s, but it can also halve – even with a relatively stable population of young males. For instance, the rate of domestic burglary in the US fell by 50% during 1988-1998 and the rate of assault by 60% during 1994-2004 (Figure 1). Similar drops in the crime rate have been documented for other countries, including the Netherlands and UK. If someone’s personal history is so important in shaping criminal inclinations, then how can it be that the rate of offending varies greatly within a short timeframe? Does anyone seriously believe that US citizens – and the same thing should hold true for the British and the Dutch – have become so much more inclined to abide by the law over the last 20 years?1 We argue that the major driver must be changes in the environment in which potential offenders operate rather than a change in their inherent criminal inclinations.
Figure 1. Victimisation of assault and burglary per 1,000 population, US, 1973-2009
Source: US National Crime Victimization Survey, various years.
Reducing criminal opportunities
A popular way of constraining offenders is through deterrence and incapacitation. Public expenditures on the threat and execution of punishment have been shown to be effective in reducing the crime rate, even though there are some concerns that the use of prison sentences as punishment has gone too far in some countries (Cook and Ludwig 2010).
Both the literature and policymakers are largely silent about strengthening victim precaution as a way of reducing criminal opportunities. That is surprising, since similar strategies are common in efforts to reduce the harm from car accidents, for instance. Both for our own good and to prevent us from hurting others, the government turned lack of precautionary behaviour into an offence. The police can pull us over and give us a ticket when not wearing seatbelts. Drinking and driving is an offence, just like tailgating, weaving in and out of traffic, and driving too fast. Actually, these types of behaviour are more than an offence, they are “not done”, against the norm set by extensive, publicly financed publicity campaigns.
Criminal opportunities are in ample supply. Most offenders are young males who are not in the business of crime but have too much time on their hands and many of them are happy to exploit opportunities whenever they see them. The police of the Dutch city of Eindhoven recently went through all the burglaries reported over a full year and found 80% of them to be in homes with either doors or windows left open. Freely accessible back alleys have been shown to make life easy for burglars (Bowers et al. 2004). Anecdotal evidence from interviews with police officers suggests that it is not uncommon for door locks to be of such poor quality that a burglar enters the home more quickly than the occupant.
These examples relate to theft, but violence may not strike like lightning from the sky either. It is for a reason that law enforcement officers, medical personnel, and workers at the benefit office receive training in how to deal with aggressive behaviour. Similarly, bar owners can invite harmful behaviour by serving beer in glasses that can be used as a weapon (Coomaraswamy and Shepherd 2003) or allowing DJs to play dance music with exceedingly high beats per minute for extended periods of time (see Rickard 2004).
Government intervention in victim precaution can enhance social welfare if victims and property insurers do not take the full costs of crime into account, including the use of publicly funded police and justice resources. Under-investment in precaution may result. In addition, precautionary behaviour may decrease the crime risk for others, in particular when protective measures are unobservable for potential offenders (Clotfelter 1977, Ayres and Levitt 1994). Paternalistic motives may provide another reason for government intervention. Many studies find that most people make systematic mistakes in preventive healthcare and decisions relating to pension saving. The way people manage the risk of crime may be no exception – although we are not aware of any theoretical or empirical work in this area.
Regulating built-in home security
In a rare move, the Dutch government decided to reduce criminal opportunities for burglary. It mandated the use of burglar-resistant locks and window and door frames in all new residential construction as of January 1, 1999. The unobtrusive regulation has now affected close to a million homes. The security was built-in and did not require any change in behaviour.
The regulatory change does not only provide a unique source of exogenous variation in victim precaution – with security now dependent on the year of construction of the home rather than the crime risk – but also allows for an analysis of the impact of large-scale government intervention in victim precaution.
Figure 2. Victimisation of burglary by year of construction of the home, the Netherlands
Source: Vollaard and Van Ours (2011, 492).
The regulated home security proved to be an effective deterrent. When comparing homes built just before and just after the change in the regulation, we find homes with the built-in security to have a 26% lower rate of burglary (Vollaard and Van Ours 2011). Figure 2 illustrates our findings – with the structural break in the burglary risk lagging the change in regulation by two years because of an average time to completion of homes of two years. We find that the intervention was successful in reducing the overall crime rate. Moreover, we do not find evidence for displacement of burglary to less-protected homes or to related property crimes such as theft from car and bicycle theft.
We find the benefits of the regulation to exceed the costs, even though the measure was uniformly applied to all homes, independent from the crime risk. The costs per prevented burglary are equal to some €1,900 (assuming a life span of homes of 75 years and a burglary rate prior to introduction of the regulation of 1.1%). The willingness to pay for preventing a burglary has been estimated at several times higher (Cohen 2004).
Our study provides evidence on how crime can be reduced without a change in the preferences of potential offenders or an increase in the threat of punishment. Government intervention in victim precaution provides an alternative way of lowering crime without the involvement of one police officer, prison guard, or social worker.
Ayres, Ian and Steven D. Levitt (1998), “Measuring positive externalities from unobservable victim precaution: an empirical analysis of Lojack”, Quarterly Journal of Economics, 113(1):43-77.
Bowers, Kate J, Shane D Johnson, and Alex F G Hirschfield (2004), “Closing off opportunities for crime: an evaluation of alley-gating”, European Journal on Criminal Policy and Research, 10:285-308.
Clotfelter, Charles T (1977), “Public services, private substitutes, and the demand for protection against crime”, American Economic Review, 67(5):867-877.
Cohen, Mark A, Roland Rust, Sara Steen, and Simon Tidd (2004), “Willingness-to-Pay for Crime Control Programs”, Criminology, 42(1):86-106.
Cook, Philip (1986), “The demand and supply of criminal opportunities”, Crime and Justice: An Annual Review of Research, 7:1-27.
Cook, Philip and Jens Ludwig (2010), “Economical crime control”, NBER Working paper 16512.
Coomaraswamy, KS and JP Shepherd (2003), “Predictors and severity of injury in assaults with barglasses and bottles”, Injury Prevention, 9:81-84.
Ehrlich, Isaac (1981), “On the usefulness of controlling individuals: an economic analysis of rehabilitation, incapacitation and deterrence”, American Economic Review, 71 (3):307-322.
Rickard, Nikki S (2004), “Intense emotional responses to music: a test of the psychological arousal hypothesis”, Psychology of Music, 32(4):371-388.
Vollaard, Ben and Jan van Ours (2011), “Does regulation of built-in security reduce crime? Evidence from a natural experiment”, The Economic Journal, 121 (May):485-504.
Wilson, James Q (2011), “Why crime is falling”, Wall Street Journal, 28 May.
1 Yes, people do believe this. In a recent essay in the Wall Street Journal, James Wilson claimed that the crime drop in the US is a cultural phenomenon (Wilson 2011).