Transcript chs2007 6798

Simulating Police Outcomes:
A Framework for Understanding
Policing Strategies
John E. Eck
University of Cincinnati
Division of Criminal Justice
Presentation at the meeting on
Crime Hot Spots: Behavioral, Computational and Mathematical Models
Institute for Pure and Applied Mathematics, UCLA
January 29 - February 2, 2007
An Initial Thought
..computer simulations are actually
philosophical thought experiments, intuition
pumps, not empirical experiments. They
systematically explore the implications of
sets of assumptions.
Daniel Dennett
Barbarian Invasions and Crime
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Standard criminology is bankrupt
A good invasion can help
Mostly raids – uncooperative, naive, and short
Taking the easy loot
Leaving some methods but little insight
Need to settle, interbreed, and stay
Welcome Barbarians!
Introduction
• Simulating police is a subset of simulating
crime
• Early simulations focused now discredited
policing strategies
• Topics
– Police Strategies – roles and effectiveness
– Simulation Framework – 4 parts
– Focused Policing
– Problem-oriented Policing
Police Strategies & Evidence
Range of Interventions
Diverse
Narrow –
Law enforcement
Community
Problem-oriented
Partnering
Public interactions
Building support
Specificity
Analysis
Tailored interventions
Evaluation
effective
ambiguous
Standard Model
Focused
Patrolling
Investigations
Fast Response
Hotspots patrols
Repeat offender invest.
Repeat victimization
ineffective
effective
general
specific
Focus
Adapted from, Weisburd, D. & J.E. Eck 2004 “What Can Police Do to Reduce Crime, Disorder and Fear?” The
Annals of the American Academy of Political and Social Science. 593: 42-65.
Strategies and Simulations
Range of Interventions
Diverse
Narrow –
Law enforcement
Community
Problem-oriented
Simulation low utility due
to lack of clarity of means
and ends
Simulations important for
a) understanding problems;
b) pre-testing interventions;
and c) evaluating results.
Standard Model
Evidence suggests
insufficient fecundity to
be a central focus. Part of
larger simulation.
Focused
Potential for simulation,
particularly first generation
simulations.
general
specific
Focus
4 Requirements
1.
2.
3.
4.
Problem/Patterns (change) are outputs
Error modeling must be built in
Standard policing part of background
Model intervention mechanisms
Basic Parts of Police Simulations
1. Simulation of Problem/Pattern
2. Reporting/Recording Filter
3. Simulation of
Standard Operations
4. Simulation of
Problem Interventions
Human eye view
of patterns
Output
Gods’ eye view of
patterns
Filtering & Calibration
Results of valid
sims of this
Crime event i occurrences
Crime event i reports to police
May not reflect
this
Crime events recorded and classified as i, j, k etc
Everybody knows the dice are loaded.
Everybody roles with their fingers crossed.
Leonard Cohen “Everybody Knows”
The Great Mystery of Crime Reporting
How does victimization experience
influence peoples willingness to report crimes to the police?
Probability
of reporting
this crime
to the
police
A
?
C
B
Number of previous victimizations
Simulating Standard Policing
1. Simulation of Problem/Pattern
2. Reporting/Recording Filter
3. Simulation of
Standard Operations
4. Simulation of
Problem Interventions
Human eye view
of patterns
Output
Gods’ eye view of
patterns
Standard Policing
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Vary density of police patrols
Vary speed of response
Vary offender removal settings
Vary filter simulation settings
Simulating Focused Policing
1. Simulation of Problem/Pattern
2. Reporting/Recording Filter
Sim.
of crime
analysis
3. Simulation
of Standard
Operations
4. Simulation of
Problem Interventions
Human eye view
of patterns
Output
Gods’ eye view of
patterns
Focused Policing
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Simulate a crime analysis function
Detects hotspots
Patrols respond to detected hotspots
Vary sensitivity, error, speed, & intensity of
analysis and patrols
• Create analogous arrangements for
focusing on offender networks and repeat
victims
Perceived Hotspots in
Offender & Victim Spaces
Commuting time
income
age
Links known
Unknown links
Simulating P-O Policing
1. Simulation of Problem/Pattern
2. Reporting/Recording Filter
3. Simulation of
Standard Operations
Sim. of problem
analysis
4. Simulation of
Problem Interventions
Human eye view
of patterns
Output
Gods’ eye view of
patterns
Problem-oriented
• Problem Analysis simulation is a simulation of the
problem simulation
– Allows testing of various heuristics
– Can be used to study knowledge limitations
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Range of interventions broad
Mechanisms for interventions diverse
Simultaneous multiple intervention points possible
Can be applied to non-police interventions
Simulating POP vs
Simulating Intervention
Simulation of Problems
Intervention
simulation
Intervention
Selection
Planning &
Evaluation
Simulation of Problem
Simulation of Problem Analysis
POP Simulation
Examples of Intervention
Simulations
• Model of crowds used to simulate
alternative parade routes (Batty 2005)
• Design street barricade arrangements
based on crime and traffic flow models
• Experimentally vary place management
intensity for landlord interventions
Batty, M. 2005 Cities and Complexity: Understanding Cities with Cellular
Automata, Agent-Based Models, and Fractals. Cambridge, MA: MIT Press.
Analysis Units in 3 Strategies
Standard Model – No analysis: patrols wander or go to most recent crime
Focused Policing – Analysis detects spatial-temporal cluster: patrol of clusters
Problem-Oriented Policing – Analysis models problem: police address process
Conclusions
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Welcome
Pay attention to existing evidence
Pay attention to useful theories
Pay attention to data errors
Pay attention to forms of policing
A Final Cautionary Note
Today's scientists have substituted
mathematics for experiments, and they
wander off through equation after
equation, and eventually build a structure
which has no relation to reality.
Nikola Tesla
Further Reading
• Center for Problem-Oriented Policing
www.popcenter.org