integrating and evaluating multiple psn strategies in chicago trace meares andrew papachristos...
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Integrating and Evaluating Multiple Integrating and Evaluating Multiple PSN Strategies in ChicagoPSN Strategies in Chicago
Trace MearesTrace Meares
Andrew PapachristosAndrew Papachristos
University of ChicagoUniversity of Chicago
Jeffrey FaganJeffrey Fagan
Columbia UniversityColumbia University
The Northern District of IllinoisThe Northern District of Illinois Taskforce included:Taskforce included:
Chicago Police DepartmentChicago Police Department ATFATF US Attorney’s Office US Attorney’s Office Cook County State’s Attorney’s OfficeCook County State’s Attorney’s Office Illinois Department of CorrectionsIllinois Department of Corrections Cook County ProbationCook County Probation City OfficialsCity Officials Multiple Community Organizations/ActorsMultiple Community Organizations/Actors Research Partners (University of Chicago Research Partners (University of Chicago
and Columbia University)and Columbia University)
The ProblemThe Problem
Homicides: Guns and Gangs Homicides: Guns and Gangs on the West-Sideon the West-Side
Goal 1aGoal 1a – – Reduce Gun HomicidesReduce Gun Homicides
Annual Homicide Counts in Chicago, 1990 to 2004Annual Homicide Counts in Chicago, 1990 to 200440
050
060
070
080
090
0
Tot
al N
umbe
r of
Hom
icid
es
1990 1995 2000 2005Year
PSN Begins
Gangs, Guns, and DrugsGangs, Guns, and DrugsTotal and Gang Homicides, 1990 to 2004Total and Gang Homicides, 1990 to 20040
200
400
600
800
1000
To
tal N
umbe
r of
Ho
mic
ide
s
1990 1995 2000 2005
Year
All HomicidesAll Homicides
Gang HomicidesGang Homicides
Goal 1bGoal 1b: Going : Going after the guns after the guns
and gun and gun offendersoffenders
Moran’s I = .378 , p =.001
Control Beats
PSN Beats
Guns and Guns and Homicides are Homicides are notnot randomly randomly distributed distributed
Treatment:Treatment: 24 beats on West 24 beats on West
SideSide
Control:Control: 30 beats on 30 beats on
South sideSouth side
ATF Gun Seizures
0 - 15
16 - 31
32 - 48
49 - 67
68 - 117
Crime IndicatorsCrime Indicators
City (All Beats)
(N = 281)Control Beats
(N = 30) PSN Beats
(N = 24)
2002 Homicide Rate22.3 (648)
49.6 (102)
75.5 (115)
2002 Gang-Related Homicide Rate
4.5 (133)
7.8 (16)
13.8 (21)
2002 Aggravated Assault & Aggravated Battery
862.2 (25005)
1851.9 (3812)
2005.4 (3053)
2002 Average ATF Gun Seizure Rate
215.6 (6252)
438.2(902)
620.8 (945)
PSN StrategiesPSN Strategies
Ex-Offenders, Gun Teams, and Ex-Offenders, Gun Teams, and ProsecutionsProsecutions
PSN Chicago - Program Design PSN Chicago - Program Design
Total PopulationTotal Population
Ex-Offender Population
Crime
Arrest Arrest
State Court
Federal Court
Disposition Disposition
General Model of Offending and Criminal Justice
System
PSN Programs and Initiatives Multi-
Agency Gun Teams and Task Forces
Multi-Agency Gun Teams and Task Forces
Case Review of all gun cases by local
and federal prosecutors.
Decision at which level to prosecute.
Case Review of all gun cases by local
and federal prosecutors.
Decision at which level to prosecute.
Offender Notification Letters
Offender Notification Meetings
Community, Media, & School Programs
PSN InterventionsPSN Interventions
1.1. Increased Federal Gun ProsecutionsIncreased Federal Gun Prosecutions
DeterrenceDeterrence
2.2. Increased Federal Prison SentencesIncreased Federal Prison Sentences
IncapacitationIncapacitation
3.3. Increased Firearms Policing Increased Firearms Policing
Supply-side strategiesSupply-side strategies
4.4. Offender Notification MeetingsOffender Notification Meetings
DeterrenceDeterrence
Normative changeNormative change
EvaluationEvaluation
Quasi-Experimental DesignQuasi-Experimental Design
Research DesignResearch Design Quasi-Experimental Panel DesignQuasi-Experimental Panel Design
Use Near-Equivalent Control GroupUse Near-Equivalent Control Group
Panel data of every “neighborhood” in Chicago from Panel data of every “neighborhood” in Chicago from
1999 to 20041999 to 2004
Multi-level modeling Multi-level modeling strategy to assess within and strategy to assess within and
between group variationbetween group variation
DataData Multiple sources – CPD, ATF, IDOC, and the CensusMultiple sources – CPD, ATF, IDOC, and the Census
Geocoded to Geocoded to police police beat – (~ to “neighborhoods”). beat – (~ to “neighborhoods”).
Quarterly from January 1999 to December 2004Quarterly from January 1999 to December 2004
VariablesVariables Dependent Variables / Outcome Measures:Dependent Variables / Outcome Measures:
Homicide Rate (logged)Homicide Rate (logged) Gun Homicide Rate (logged)Gun Homicide Rate (logged) Gang-Related Homicide Rate (logged)Gang-Related Homicide Rate (logged) Aggravated Assault and Battery Arrest Rate Aggravated Assault and Battery Arrest Rate
(logged)(logged)
Neighborhood Social Indicators:Neighborhood Social Indicators: DeprivationDeprivation Concentrated ImmigrationConcentrated Immigration Residential StabilityResidential Stability Spatial Lag of beat-level Homicides (Moran’s I)Spatial Lag of beat-level Homicides (Moran’s I)
PSN Treatment VariablesPSN Treatment Variables
1.1. Offender Notification Meetings Offender Notification Meetings – percent of offenders – percent of offenders in beat who have attended a meetingin beat who have attended a meeting
2.2. Federal Prosecutions Federal Prosecutions – number of prosecution in beat – number of prosecution in beat (logged)(logged)
3.3. Federal Prison Sentences Federal Prison Sentences – person-month sentences – person-month sentences (logged)(logged)
4.4. ATF Gun SeizuresATF Gun Seizures – number of guns seized by beat – number of guns seized by beat (logged)(logged)
5.5. Index of Components Index of Components – additive score of where each – additive score of where each beat falls on quintiles of other predictors (ranges from beat falls on quintiles of other predictors (ranges from zero to 20). zero to 20).
Annual Homicide Rates, 1991 to 2004Annual Homicide Rates, 1991 to 2004
PSN Group
Control Group
Other areas of City
PSN BeginsPSN Begins
2040
6080
100
Ho
mic
ide
Rat
e p
er 1
00,0
00
1990 1995 2000 2005year
Change in Neighborhood Homicide Rates, Before Change in Neighborhood Homicide Rates, Before and After Start of PSNand After Start of PSN
PSNPSNNeighborhoodsNeighborhoods
Control Control NeighborhoodsNeighborhoods
-10
-50
510
mea
n o
f ch
ang
e
Change in Monthly Homicide Rates in PSN AreaChange in Monthly Homicide Rates in PSN Area
1st Parolee Forum
1st PSN Prosecution
02
46
810
Hom
icid
e R
ate
per
100,
000
01 Jan 00 01 Jul 01 01 Jan 03 01 Jul 04 01 Jan 06
Figure 3. Change in Quarterly Homicide Figure 3. Change in Quarterly Homicide Rates by Assignment GroupsRates by Assignment Groups
PSN GroupPSN Group
Control GroupControl Group
Rest of CityRest of City
12
34
56
Ho
mic
ide
Rat
e p
er 1
00,0
00
01 Jan 00 01 Jul 01 01 Jan 03 01 Jul 04 01 Jan 06
Summary of FindingsSummary of Findings Find Find negative negative effect on Homicides for:effect on Homicides for:
Forums – largest effect.Forums – largest effect. ProsecutionsProsecutions ATF SeizuresATF Seizures Additive IndexAdditive Index
No significant effect of:No significant effect of: Sentence Length on HomicidesSentence Length on Homicides Any predictor on Agg. Battery and Agg Any predictor on Agg. Battery and Agg
Asslt. Asslt.
Summary of PSN “Treatment” Effects on Quarterly Summary of PSN “Treatment” Effects on Quarterly Neighborhood Homicide RatesNeighborhood Homicide Rates
-1
-40.1
-2.2 -2.7-0.8
-11
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10Control
Variables ForumsGun
Recoveries
Prosecutions
Sentence Length
Combined Effect
**N.B.: Random Effects Poisson Regression
Percentage decrease in Log(Homicide Rate) associated with a one-unit increase in PSN “treatment”
ConclusionsConclusions The observed drop in homicide is larger The observed drop in homicide is larger
in the treatment vs. control area (35 in the treatment vs. control area (35
percent). percent). Find a significant negative relationship Find a significant negative relationship
between various PSN interventions and between various PSN interventions and
homicidehomicide Forums appear to be having the largest Forums appear to be having the largest
effect, effect, butbut there is a clear additive there is a clear additive
effect.effect.
This paper can be found at. . .This paper can be found at. . .
Social Science Research Network:Social Science Research Network:
www.ssrn.comwww.ssrn.com
DirectionDirection Individual Level data:Individual Level data:
Recidivism of those who attend the forum as Recidivism of those who attend the forum as
compared to non-attendees?compared to non-attendees?
The Chicago Gun ProjectThe Chicago Gun Project Offender perceptions of legitimacy/legal Offender perceptions of legitimacy/legal
authority?authority? The role of social networks in:The role of social networks in:
Gun marketsGun markets Patterns of OffendingPatterns of Offending Nexus between community and offender capitalNexus between community and offender capital