<P> Criminal justice scholars lacked a systematic approach to measuring crime displacement until the introduction of the weighted displacement quotient (WDQ) by rs and Johnson (2003). Although this tool is not widely recognized, its use has made displacement statistically recordable . WDQ is one part of understanding the effects of targeted law enforcement, but the ease with which the system can be used comes from its being a simple series of statistical tests on data . WDQ works as an overall process, and is an effective technique to measure the geographical displacement of crime . In addition to measuring this, the tool can also measure the diffusion of benefit of law - enforcement efforts . </P> <P> A study by Catherine Phillips for the Nottingham Trent University Division of Criminology reviewed the existing literature and performed a secondary analysis on the published results of empirical data . An orthodox view of displacement is considered throughout the study: crime displacement is considered inevitable, but is less than anticipated and may lead to a diffusion of benefits . Philips conducted the study to "...discover whether the criminological orthodox' knowledge' that interventions do not result in 100 - percent crime displacement, and may even lead to a' diffusion of benefits'--defined as' the unexpected reduction of crimes not directly targeted by the preventive action" could be proven (Clarke and Weisburd, 1994: 165). Reviewing a wide variety of published empirical data, Phillips found that displacement is not inevitable, but is very common . Sixty - three percent of the cases studied showed some sort of displacement, and a review of offender studies demonstrated 84.6 percent displacement . These results challenge the orthodox view on crime displacement, raising the question of whether the orthodox view is biased . </P> <P> The second study was conducted by Matthijs F.J. Vijlbrief for the National Crime Squad of the Netherlands Police Agency in Driebergen, the Netherlands . Using the Dutch synthetic market as a case study, Vijlbrief (2012) assessed the role of displacement in organized crime . With the increase of barriers by government officials to obtaining precursor and essential chemicals, the question is how criminal organizations respond to a shortage of chemicals . Illegal organizations began by substituting other chemicals for specific precursors, making the drugs more dangerous to those using them . Criminals were initially not displaced, instead adapting to the new regulations . The study of potential adverse effects is a valuable tool in creating situational crime - prevention policies . By evaluating potential effects, a policy can be predicted to have a positive or negative result . Vijlbrief (2012) states in his research that "Some measures can be said to have a waterbed effect: repression of criminal activities in one location may cause an increase in the same criminal activities somewhere else . Displacement is not limited to geographical effects . Perpetrators may also shift their activities to completely different types of crime, or even continue to commit the same crime using different methods or means" (p. 199). Studying the relationship between interventions by law - enforcement bodies and displacement effects proved complex . One conclusion in the study by Vijlbrief (2012) is that "there is limited attention for displacement effects or the diffusion of benefits" (ibid; Kim et al. 2007); "It is difficult to isolate the effect of a given measure because neighboring factors always have an influence" (Shukla and Bartgis 2009, p. 354). Measuring displacement effects for an illegal organization in the synthetic drug market is complex, since the market is multifaceted and extensive . Organized criminals are likely to adapt their methods to changing circumstances, leading to displacement; this assumes that crime organizations have the resources to adapt to policy change . </P> <P> There is also a large research literature examining the extent to which the introduction of CCTV causes spatial displacement of crime . A systematic review of this literature published in 2009 concluded that CCTV schemes "usually showed evidence of no displacement rather than displacement or diffusion of benefits". Similarly, a more recent review of randomized controlled trials and natural experiments assessing the effects of CCTV concluded that the "evidence on the prevalence of displacement and diffusion of benefit was mixed". </P>

The most common form of displacement considered in evaluations is tactical displacement