Research on crime displacement began to be carried out in a more systematic manner during the 1990s. There was a significant step forward when research was conducted in Canada (Gabor, 1990) and the United States (Eck, 1993) specifically studies on crime displacement and found it to be much less of a problem than what have generally been thought of. As suggested by Eck (1993), crime displacement occurred where it was most likely to be similar targets or similar and adjacent areas. Although the findings were greatly positive, there was, not surprisingly, a variation between different crimes. Drug dealing, for example, had been found to be susceptible to crime displacement (Rengert, 1990; Sherman, 1990; Caulkins, 1992; Eck 1993), which echoed the views of Barr and Pease (1990) on crime displacement. In 1994, the Ministry of Justice in Holland has tasked Professor Rene B.P. Hesseling to conduct a research systematically by analyzing all the available literatures on crime prevention measures concentrating on crime displacement looking for its related evidences. This major task took him fourteen months by reviewing 55 published articles and research related to crime displacement. The summary of the research revealed that crime displacement is possible, but not an inevitable consequence of crime prevention (Hesseling, 1994). And, if crime displacement does occur, it will be limited in its size and scope. This conclusion is supported by other review studies on this topic (Clarke, 1999). It is believed that criminologists have generally shown little interest in crime displacement prevention. This lack of interest stems from what was regarded as two mistakes of modern criminology. The first mistake is the problem of explaining crime that has been confused with the problem of explaining criminals and the second mistake is the problem of controlling crime with that of dealing with criminals (Moss &Pease, 1999).
In 1999, evaluations were carried out by Building Research Establishment (BRE) (Pascoe, 1999), Gwent Police in South Wales (Brown, 1999) and Applied Criminology Group, University of Huddersfield (Armitage, 1999). The results of all three studies were very positive and the issue of crime displacement was discussed in depth. Although it is not specifically focused on crime displacement, the BRE reported that it has not displace crime to the neighbours and the report found no evidence of crime displacement from prevented burglary into other crime (Brown, 1999). As for crime displacement, the evidence from the broad based analysis suggested that there is a diffusion of benefits, as opposed to displacement of crime.
Crime displacement inevitably occurs with the implementation of policing efforts which are largely based on unfounded suppositions rather than empirical facts (Eck, 1993; Hesseling, 1994; Hill & Pease, 2001). Research also shows that crime displacement is unlikely in the aftermath of broader community development programs (Roman, Cahill, Coggeshall, Lagerson, & Courtney, 2005; McLennan & Whitworth, 2008) and more focused policing initiatives that centred on hot spots crime area (Braga, 1999; Weisburd, 2006; Braga, 2007). An evaluation of the Weed and Seed program in Miami, Florida, found that spatial diffusion of benefits occurred more commonly than spatial displacement (Roman, 2005).
Crime displacement inevitably occurs in the aftermath of problem-led policing efforts which are largely based on unsupported suppositions rather than empirical facts. Research has consistently found that crime displacement is the exception rather than the rule and that diffusion of benefits is just as likely and sometimes more likely to occur (Eck, 1993; Hesseling, 1994; Hill & Pease, 2001). In cases where some crime displacement occur they tend to be less than the gains achieved by the response and found that crime displacement and diffusion are equally likely to occur (Guerette & Bowers, 2008). An analysis of 13 studies, which allowed for the assessment of the prevention project’s overall outcomes while accounting for spatial displacement and diffusion effects, found that when spatial displacement did occur, it tended to be less than the response effect. In short, the responses were still beneficial on average (Guerette, Rob & Kate, 2009). Figure 2.11 presents some of the results from this analysis. Crime displacement tends be observed in 26 percent of the instances, where it is examined, and diffusion is observed 27 percent of the time. The research also suggests that temporal displacement is most common (occurring 36 percent of the time), followed by target (33 percent), offense (26 percent), spatial (23 percent) and tactical (22 percent). As for diffusion, spatial diffusion seems to be the most common (occurring 37 percent of the time) followed by target (24 percent), offense and temporal (each at 16 percent), and tactical (12 percent). Previous reviews of crime prevention evaluations also found that the extent of crime displacement is usually limited. One of the most comprehensive reviews of the extent of crime displacement conducted by Guerette and Bowers (2009) found that crime displacement and diffusion are equally likely to occur. An evaluation of the New Deal for Communities (NDC) program in the United Kingdom discovered that, among 383 buffer zones, spatial diffusion of benefits was observed in 23 percent of the zones, while spatial crime displacement was observed in only 2 percent of the zones. The remaining 75 percent showed no signs of crime displacement or diffusion (McLennan & Whitworth, 2008). Also, across the buffer zones offense diffusion was more common than offense displacement. A review of crime hot spots policing of the five studies that examined crime displacement and diffusion effects found that none of the review reported any substantial immediate spatial displacement of crime into areas surrounding the targeted locations. Four other studies found possible diffusion effects (Braga, 2007). Research conducted to identify the presence of crime displacement in a problem-oriented policing project was conducted in Lowell, Massachusetts and found no significant crime displacement to the areas immediately surrounding the targeted places (Braga & Bond, 2008). It should be noted, however, that there may be times when crime displacement is simply undetectable. Criminals may move to other jurisdictions or switch to other crimes from which no data can be obtained. Due of this, the research findings reported above may undercount the true extent of crime displacement effects. Criminal’s familiarity with locations also provides lower risks to them because they can identify entry and exit points more readily which allow them to approach and leave crime scenes in shorter time. Criminals’ spatial familiarity is primarily determined by the known places and the surrounding area that they frequent as part of their normal living routines. This provides minimal effort for criminals while allowing them to commit crimes easily in their zone. For target and tactical crime displacement, familiarity means criminals are more likely to select similar target and use the same tactics they have used in former crimes. The criminals will not engage on targets they are not familiar. Most criminals acquired skill sets from peer groups and other delinquent associations as well as through their direct and indirect experiences of committing crime (Cornish, 1994). The use of existing skill sets is much less likely in the absence of other available crime targets. Highly motivated criminals may expend the effort to acquire new skill sets, but the more common opportunistic criminal is less likely to do so. The presence of crime opportunities also determines when and where crime displacement may occur as stipulated in Figure 2.12. Crime displacement is more likely to happen where there are suitable crime targets. This is contingent upon the criminals’ motivation and familiarity with the crime targets and tactics required to carry out the crime. Responses that occur adjacent to areas that have unprotected crime targets are more likely to experience some level of crime displacement compared to those that do not.