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Spatial & temporal mapping of futurecriminal risk as a catalyst forenforcement & reduction activity
Derek Johnson, Northumbria University, England
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Jan/Feb 2005 analysis identifies near repeat phenomena.
Feb/March reduction intervention devised
April – reduction intervention begins in pilot areas
January 2006 – evaluation shows overall reducing levels of
burglary crime across the town - additional 6% reduction in
intervention areas
Near repeat phenomena no longer apparent (i.e. not
statistically significant)
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Ripleys K analysis residential burglary 10 monthspre & post intervention.Pre intervention Post intervention
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Near repeat offences still taking place
Serial offenders responsible?
Common offenders?
Identify & describe personal space-time patterns?
Predict future burglary locations?
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y
93,000
92,500 9 4
92,000
91,500
5+7
91,000 2 13 6 11
3 1 10
90,500 8+12
4 0 7 , 0
0
4 0 7 , 5
0
4 0 8 , 0
0
4 0 8 , 5
0
4 0 9 , 0
0
4 0 9 , 5
0
x
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y
93,000
92,500 9 4
92,000
91,500
5+7
91,000 2 13 6 11
3 1 10
90,5008+12
4 0 7 , 0
0
4 0 7 , 5
0
4 0 8 , 0
0
4 0 8 , 5
0
4 0 9 , 0
0
4 0 9 , 5
0
x
8/13/2019 Spatial & temporal mapping of future criminal risk as a catalyst for enforcement & reduction activity
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Time ----------->
D i s t a n c e - - - - - >
x x
x
x
x
Close offences x x x x
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Area period Volume Detected % detected No of offenders
Area 1 ‘02-’06 5,610 1,254 22.35 350Area 2 ‘02-’06 2,175 404 18.57 260
Offender Data
No of offenders
> 9 burglary offences 44In Bournemouth or Poole
No of series Volume>1 identifiable series 14 29 457of burglary crimes withinoffending history
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0
2
4
6
8
10
12
14
1 2 3 4 5 6 7 8 9 10 11
f r e
q u e n c y
Distance bins (Km)
Histogram of inter event
distances
0
1
2
3
4
5
1 2 3 4 5 6 7
F r e q u e n c y
Distance Bins (Km)
Histogram of future
nearest neighbour
distances
Q1 Std dev. Mean Median Skew Range
Min.
Distance
0.523 2.406 2.145 1.084 1.323 6.441
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0
1
2
3
4
5
6
0 6 12 18 24 30
F r e q u e n c y
Bin - days
Histogram of
minimum distancetime spans
mean 6.25median 4.50
total days 40.00
min interval 1.00
maxinterval 21.00
std 6.30
pskew 0.83Quartile 1 3.00
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Serial offenders display ‘near repeat’ behaviour
Serial offenders are consistent over time,
particularly with regard to what they consider tobe ‘close’ in distance
Time and distance parameters can be
calculated for ongoing ‘real time’ crime series
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Event 1 2 3 4 5 6 7 8 9 10 11
1 X
2 X
3 X
4 X
5 X
6 X
7 X
8 X
9 X
10 X
11
1 2 3 4 5 6 7 8 9 10 11 12 13
1
2
3 X
4 X
5 X X
6
7 X
8 X X
9
10 X
1112
13
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•
Offenders commit near repeats
•Tend to commit near repeats at about the median
distance from a previous offence location
•And at about the median time lapse from a
previous offence
•Low space/time index scores describe a distancefrom a previous offence where no offending is likely
until a certain amount of time has elapsed
So now we know…….
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Ashton, J., Brown, I., Senior, B., Pease, K. 1998. “Repeat Victimisation: OffenderAccounts.” International Journal of Risk, Security and Crime Prevention. v3: pp269 -
279.Johnson, D. 2007. “The Near repeat burglary phenomenum.” in Chainey, S. &Ratcliffe, J. (eds) Crime mapping case studies: practice and research’. Chichester: JohnWiley & sons - Forthcoming.Johnson, S.D., Bowers, K.J. and Pease, K. 2005.“Predicting the future or summarising
the past? Crime mapping as anticipation.” in Smith, M., Tilley, N. (eds) Crime Science.New approaches to preventing and detecting crime. Cullompton: Willan Publishing.pp145 - 163.Levine, N. 2004. “Crimestat: A Spatial Statistics Program for the Analysis of CrimeIncident locations.” Ned Levine and Associates, Houston TX, and the National
Institute of Justice Washington D.C.Townsley, M., Homel, R., Chaseling, J. 2000. “Repeat Burglary Victimisation: Spatial &Temporal Patterns.” The Australian & New Zealand Journal of Criminology. v33,1:pp37-63.
