Simulating Police Outcomes:

A Framework for UnderstandingPolicing Strategies

John E. EckUniversity of Cincinnati

Division of Criminal Justice

Presentation at the meeting onCrime Hot Spots: Behavioral, Computational and

Mathematical ModelsInstitute 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

• 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

Standard Model Focused

Community Problem-oriented

Focus

general specific

Ran

ge o

f In

terv

entio

ns

Narrow –Law enforcement

Diverse

ineffective

PatrollingInvestigationsFast Response

Hotspots patrolsRepeat offender invest.Repeat victimization

effective

PartneringPublic interactionsBuilding support

ambiguous

SpecificityAnalysisTailored interventionsEvaluation

effective

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

Standard Model Focused

Community Problem-oriented

Focus

general specific

Ran

ge o

f In

terv

entio

ns

Narrow –Law enforcement

Diverse

Evidence suggests insufficient fecundity to be a central focus. Part of larger simulation.

Potential for simulation, particularly first generation simulations.

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.

4 Requirements

1. Problem/Patterns (change) are outputs2. Error modeling must be built in3. Standard policing part of background4. Model intervention mechanisms

Basic Parts of Police Simulations

1. Simulation of Problem/Pattern

4. Simulation of Problem Interventions

3. Simulation of Standard Operations

Output Gods’ eye view of patterns

Human eye view of patterns

2. Reporting/Recording Filter

Filtering & Calibration

Crime event i occurrences

Crime event i reports to police

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”

Results of valid sims of this

May not reflect this

The Great Mystery of Crime Reporting

?Number of previous victimizations

Probability of reporting this crime to the police

A

B

C

How does victimization experience influence peoples willingness to report crimes to the police?

Simulating Standard Policing

1. Simulation of Problem/Pattern

4. Simulation of Problem Interventions

3. Simulation of Standard Operations

Output Gods’ eye view of patterns

Human eye view of patterns

2. Reporting/Recording Filter

Standard Policing

• 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

4. Simulation of Problem Interventions

3. Simulation of Standard Operations

Output Gods’ eye view of patterns

Human eye view of patterns

2. Reporting/Recording Filter

Sim. of crime analysis

Focused Policing

• 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

age

income

Links knownUnknown links

Commuting time

1. Simulation of Problem/Pattern

Simulating P-O Policing

4. Simulation of Problem Interventions

Output Gods’ eye view of patterns

Human eye view of patterns

Sim. of problem analysis

2. Reporting/Recording Filter

3. Simulation of Standard Operations

Problem-oriented• Problem Analysis simulation is a simulation of the

problem simulation– Allows testing of various heuristics– Can be used to study knowledge limitations

• 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

Simulation of Problem Analysis

Intervention Selection

Planning & Evaluation

Simulation of Problem

Intervention simulation

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 StrategiesStandard 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• 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