Data Driven Policing:Data Driven Policing:
Homicide Concentration and Homicide Concentration and Distribution Patterns in LondonDistribution Patterns in London
Detective Superintendent Mark Jackson&
Barak Ariel, PhD
• Is Homicide a random event in time?
• Is Homicide a random event in space?
• What are the possible links between homicide locations, offenders, victims and other factors, at the micro-place level?
Research Questions?
The stability of crime trends at places over time suggests a “strong coupling” of crime to place
David Weisburd, Cody W. Telep, Anthony A. Braga (2010). The Importance of Place in Policing: Empirical Evidence and Policy Recommendations. Bra Publications
Place-Based Criminology
• 74% of serious gun crime assault was committed in 5% of street and intersections
(Braga et al 2010)
• 5% of addresses/intersections produce 100% of the calls for predatory crimes, i.e. robbery
(Sherman et al 1989)
• 3.5% of addresses account for 50% of crime calls (Sherman et al 1987)
(some of the) Research Evidence:
London Metropolitan Police Data:
• 10 year period from (1.4.2000 - 31.3.2010) within the Metropolitan Police area of London
• Homicide Locations = 1,664 (98.2% geo-coded)
• Victims Locations = 1,714 (87.3% geo-coded)
• Offenders Location = 2,382 (84.3% geo-coded)
• Socioeconomic Deprivation Measures for 4,760 LSOAs
Homicide Offence locations by Borough
Offences by borough
100 to 125 (1)75 to 99 (5)50 to 74 (10)25 to 49 (10)1 to 24 (6)0 (1)
Homicide Offence locations by Ward
Offences by wards
16 (1)12 to 15 (3)9 to 12 (15)6 to 9 (63)3 to 6 (182)1 to 3 (233)0 (127)
LSOA Characteristics
Greater
Metropolitan
City
LSOA
Homicide
Locations
LSOA
Victim
Locations
LSOA
Offender
Locations
N 4,760 1,240 1,202 1,386
Population size 7.1-7.4M 1,634 1,496 2,030
Mean N of persons 1,505-1,626 1,660 1,645 1,585
Area (Hectares) 32.9 31.4 27.4 39.4
Density rate per Hectare 84.1-90.8 93.4-101.7 97.7-105.9 69.2-73.1
• 72% of London's LSOAs (n=3,414) did not have a resident accused of homicide
Homicide Offenders
• 75.5% (n=3,597) of LSOAs did not have a resident victim of homicide
Homicide Victims
• There are predictable “hot times” of homicide
• The stability of homicide trends at places over time suggests a “strong coupling” of:
1. Homicides to place (6% 42%)
2. Homicide offenders to place (9% 53%)
3. Homicide victims to place (5% 35%)
Summary 1
• 2% of homicide offenders kill within their LSOA
• 60% of victims are killed within their LSOA
• Medium-size relationship between overall crime patterns & deprivation levels with: 1. Homicide LSOA (ES = 0.5)
2. Homicide victims LSOA (ES = 0.5)
• Small but negative relationship between overall crime patterns & deprivation levels with: Homicide offenders (ES = -0.14)
Summary 2