Prospective crime mapping in operational context Final report

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2.5 Illustration of a simple nearest neighbour analysis for two data sets 262.6 Nearest neighbour index: retrospective and prospective methods 274.1 Similarity in time of day for near-repeats and unrelated burglaries 404.2 An example image of the final GUI 415.1 Promap dissemination process across ‘A’ Division 485.2 A series of predictions for one area 495.3 Timeline for prospective mapping pilot in ‘A’ Division 516.1 Time-series graph of the count of burglary before and during pilot 616.2 Changes in the proportion of burglaries committed during the evening overtime (for events for which the interval between the earliest and latest reportingtimes was less than eight hours) 636.3 Changes in the proportion of burglaries committed during the morning overtime (for events for which the interval between the earliest and latest reportingtimes was less than eight hours) 646.4 Changes in the proportion of burglaries committed during the daytime overtime (for events for which the interval between the earliest and latest reportingtimes was less than eight hours) 656.5 Changes in the proportion of burglaries committed during the evening overtime (for events for which the interval between the earliest and latest reportingtimes was less than eight hours) 66A1.1 Internal application utilising existing GIS for visualisation 75A1.2 Stand-alone application utilising existing GIS 76A1.3 Stand-alone application with integrated GIS 77A3.1 Changes in the spatial distribution of risk following the introduction of the pilot 88A3.2 Lorenz curves showing the distribution of burglary risk 90A3.3 An illustration of a triple (bottom) and quad chain (top) 91A3.4 The proportion of events belonging to different k-event series before andduring the pilot 93A5.2 An enlargement of the shift analysis options 96A5.3 An example of fictitious prospective map 96A5.4 Map navigational options 97A5.5 Prospective map magnified to neighbourhood level 97A5.6 Prospective map magnified to street level 98A5.7 Prospective map magnified to household level 98iv
Executive summaryThe systematic identification and management of risk is one element in the Home Office’sreform plan published on 19 July 2006, with a stated emphasis on proactivity in riskmanagement. The research reported here provides an innovative means of doing preciselythat in respect of one offence, describing and applying a technique whose extension to alloffence types would make a significant contribution to realisation of the Home Office’s reformagenda.Knowing when and where to deploy resources is pivotal to the crime reduction enterprise.The attempt to identify and police ‘hotspots’ of crime has for some time been a part of crimereduction strategy. The positive effects of such measures have been acknowledged, with arange of interventions based on this approach having significant impacts on levels of crime.The aim of the project reported here is to understand the regularities in patterns of burglaryacross a range of geographical areas and to develop and test an emerging forecastingtechnique, prospective mapping, thereby helping the police and their crime reduction partnersto prevent and detect more crime.The risk of burglary is not evenly distributed – some areas experience more burglary thanothers. Within areas, some homes are victimised more than the rest. However, little researchhas focused on the accurate prediction of which areas and locations are most likely toexperience burglary next. Research concerned with crime mapping has focused almostexclusively on the description of what happened last week, last month or over the last year,with the implicit assumption that the future will be much like the past. Insofar as crime moves(and it does), such an approach is at best sub-optimal. The current study sought to developan accurate way of forecasting where burglary is most likely to next occur, and to decidewhether the resulting system had potential for use in operational policing. In addition toaddressing the technical issues of how to forecast future patterns of burglary, the authorsattempted to identify issues of implementation that might impede police adoption of predictivemapping systems and how such mapping might be integrated with other approaches to crimereductionSpatial and temporal patterns of crime are fluid. Research by the authors and others haddemonstrated that the risk of burglary appears not only to move, but to cluster in space andtime in much the same way as a communicable disease. When a burglary occurs at onehome, another is likely to occur swiftly nearby. As time elapses, this risk decays so that afterfour to eight weeks, homes located near to a previously victimised home experience only alevel of risk normal for the area in which they are located. If such patterns are ubiquitous (anotion supported by the work reported), the risk of burglary moves. The consequence is thatthe location of future events might be better predicted by means more sophisticated than thesimple extrapolation of past patterns.The central aims of the project were as follows.• To determine whether patterns of burglary were communicable across diverse areasof the East Midlands, and if so, whether the pattern varied between areas.• To develop a predictive mapping system usable in an operational policing context.• To test the accuracy of the system and compare it with contending alternatives.• To determine how the system could be used operationally, identify obstacles toimplementation, establish how it was received by those who might use it, and identifynecessary refinements.• To provide an idea of the likely efficacy of the system during a field trial by evaluatingits impact on crime and influence on crime reduction strategies in the area.v
Page 2 and 3: 1. UCL JILL DANDO INSTITUTE OF CRIM
Page 4 and 5: ContentsAcknowledgementsExecutive s
Page 8 and 9: Project outcomesPatterns of burglar
Page 10 and 11: those that involved collaboration w
Page 12 and 13: 1. IntroductionThis report represen
Page 14 and 15: optimally calibrated system, the go
Page 16 and 17: e ij = n .j x n i.nWhere, e ij is t
Page 18 and 19: Table 2.2: Knox ratios for Mansfiel
Page 20 and 21: Table 2.6: Monte-Carlo results for
Page 22 and 23: Table 2.10: Weekly Knox ratios for
Page 24 and 25: Table 2.14: Monte-Carlo results for
Page 26 and 27: Figure 2.1: The five policing areas
Page 28 and 29: The results for area 5 again demons
Page 30 and 31: The bandwidth used to generate the
Page 32: a densely populated urban area this
Page 35 and 36: Table 2.24: Average number of crime
Page 37 and 38: Patrolling efficiencyAs discussed e
Page 39 and 40: 3. Tactical options and selecting a
Page 41 and 42: Selecting a pilot siteThe decision
Page 43 and 44: Table 3.2: Tactical options matrixT
Page 45 and 46: Type ofinterventionStudyUse ofintel
Page 47 and 48: Other potential tactical optionsAt
Page 49 and 50: 4. System development and evolution
Page 51 and 52: the same time of day as each other
Page 53 and 54: unfortunately, implementation or us
Page 55 and 56: any tactical options were employed
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the end of the pilot. In addition t
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Figure 5.1: Promap dissemination pr
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the busy schedule of the new Divisi
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Tactical deliveryCommand Team daily
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Table 5.3: Number of respondents wh
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permitted, up to four plain clothed
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observation made by those who used
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A simple time-series analysis (see
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Two approaches were used to compute
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Figure 6.3: Changes in the proporti
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Figure 6.5: Changes in the proporti
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With respect to implementation real
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ReferencesAggresti, A. (1996) An In
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Johnson, S.D., Summers, L., and Pea
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Appendix 1. The information technol
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Figure A1.2: Stand-alone applicatio
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Recommendations that may be realise
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Section 1: knowledge and understand
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Extra Comments (please outline any
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In relation to the evaluation of in
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Time-series analysisFor the purpose
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Figure A3.1: Changes in the spatial
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Figure A3.2: Lorenz curves showing
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To recapitulate and elaborate, the
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Concluding comments on methodThe te
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Figure A5.2: An enlargement of the
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Figure A5.6: Prospective map magnif
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Produced by the Research Developmen
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Prospective crime mapping in operational context Final report

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