Lawrence W. Sherman
Heather Strang
Cambridge University

Research is not enough: pushing research into practice

• Advancing the evidence base
--Offenders
--Places
--Victims
• Advancing Police Agency Uses of Evidence
Durham, W. Australia, Uruguay, Trinidad &
Tobago,
• Advancing Governmental Use of Evidence

Triple-T Against Crime & Harm
L.W. Sherman Crime & Justice 42 (2015)
Testing
Targeting Tracking
Evidence-
Based
Policing
4

Targeting Testing Tracking
Power Few
Prediction
Triage
Sample Measure
Comparison Feed Back
Integrity Correction

Tracking Patrol in Murder Spots 2014

Engage
+
Reassure:
Legitimacy
Predict
+
Prevent:
Harm
Respond
+
Resolve:
Demand
Targeting
Innovate
+
Evaluate
Testing Tracking

COMPSTAT (New York) Cop-Stat (Trinidad)

If Feed Back does not work,
SSP David Abraham
Apply corrections
--Ride along at night
--Change leaders
--Incentives
--Discipline

How Much Patrol Dosage is
Enough?
• Most hot spots RCTs do not even measure it in
Experimental areas.
• Let alone in control areas
• No check on integrity
• Even bigger a problem for police ops than for research
• Trinidad & Tobago now monitors dosage like a hospital

TARGETING
Pioneers use of GPS
For geo-fencing 230 homicide hot spots for more patrol, stops
TESTING
Uses RCT to estimate effects on murder, guns
TRACKING
Pioneers weekly feedback to drive up patrols, drive down murder
Stephen Williams, MSt
Commissioner of Police

• Before:
71 murder/shootings EXP
71 murder/shooting Control
• During 56 murder/shootings EXP
95 murder/shooting Control
• EXPECT 95; RESULT 56; 95-56 = 39 prevented
41% Less than Control

14

T-20 vs. Control-20
2012-2013

Difference in Differences Data
Statistics for each study Pairs Std diff in means and 95% CI
St. Joseph-Central
Arouca-Arima
St. Clair-Carenage
St. James-San Juan
-0.428
-0.366
-0.341
-0.306
Mon Repos-Sangre Grande -0.276
La Horquetta-Siparia -0.255
Barataria-Couva
Penal-Malabar
-0.240
-0.229
Rio Claro-Barrackpore -0.222
Ste. Madeline-Four Roads -0.170
Woodbrook-Gasparillo
Princes Town-Marabella
-0.078
-0.056
Cunupia-Belmont
Valencia-Pinto Post
Morvant-West End
Caroni-Maraval
-0.045
-0.002
-0.001
0.002
Point Fortin-Mayaro
Chaguanas-San Fernando
Tunapuna-Freeport
St.Maragrets-Oropouche
0.150
0.184
0.245
0.299
-0.106
0.150
0.149
0.149
0.149
0.149
0.149
0.149
0.149
0.151
0.150
0.150
0.150
0.150
0.150
0.150
0.150
0.149
0.149
0.150
0.150
0.033
0.023 -0.724 -0.133
-2.841
0.004
0.023 -0.660 -0.071
-2.434
0.015
0.023 -0.635 -0.047
-2.272
0.023
0.022 -0.600 -0.012
-2.042
0.041
0.022 -0.570
0.017
-1.845
0.065
0.022 -0.549
0.038
-1.706
0.088
0.022 -0.533
0.053
-1.603
0.109
0.022 -0.522
0.064
-1.530
0.126
0.022 -0.515
0.071
-1.487
0.137
0.022 -0.463
0.122
-1.140
0.254
0.022 -0.371
0.214
-0.525
0.599
0.022 -0.348
0.236
-0.375
0.708
0.022 -0.337
0.247
-0.302
0.763
0.022 -0.294
0.291
-0.011
0.991
0.022 -0.293
0.291
-0.007
0.994
0.022 -0.291
0.294
0.011
0.991
0.022 -0.142
0.443
1.007
0.314
0.022 -0.108
0.477
1.235
0.217
0.022 -0.048
0.539
1.640
0.101
0.022
0.005
0.593
1.995
0.046
0.001 -0.172 -0.041
-3.173
0.002
-1.00
-0.50
More Crime in Control
0.00
0.50
More Crime in Treatment
1.00
Meta Analysis

Vol. 25, No. 1
March 2015
Evidence-Based
Policing: From
Academics to
Professionals
Sherman & Murray, guest editors http://icj.sagepub.com/conten t/25/1.toc

1. Targeting Evidence for Policing
What Works, What Doesn’t
Philadelphia Guns Suffolk DV
Visits (Dyads)
Turning Point HMOs
E-Tag IOM CT & Trust
Hants DV
(CARA)

3d Philadelphia Hot Spots RCT
Temple University
81 Hot “Spots”
(22 football fields)
Elizabeth Groff
3 groups, block RCT
Jerry Ratcliffe
20 Experimental, 7 control
--POP (20+7)
--Patrol (20 + 7)
--Offender Focus (20 +7)

E. Groff, J. Ratcliffe et al CRIMINOLOGY 2015
Philadelphia officers made frequent contact with prolific offenders identified by INTELLIGENCE units, from
1. making small talk with a known offender to
2. serving arrest warrants for a recently committed offense.
The most frequent tactic used was
3. surveillance followed by
4. “aggressive patrol” and the
5. formation of INTELLIGENCE partnerships with beat officers; some districts used flat-screen televisions in their roll-call rooms to display photos and convey other intelligence gathered on these prolific offenders to all district personnel.
(the future: I-Phone ICT app for facial-recognition?)

50% Reduction in Serious Violence
Rates in “Hot Spots”
• 20 Offender-Focus (O.F.) Hot Spots, 7 controls, 12 weeks
• More Patrol, POP: NO REDUCTION
• NOT NUMBERS of CONTACTS: equal frequency
• MORE TARGETED: who was stopped?
• More LEGITIMATE?
Only known bad guys
NOT indiscriminate stopping
• NO Displacement surrounding areas

• Complex statistical analyses
• No raw numbers of crimes
• Unfamiliar tests
• No way to explain except “half as much”

Turning Point Project:
Offender-Desistance Policing
Peter Neyroud
Jamie Hobday
Molly Slothower
Et al
• Deferred Prosecution
• Offer to have NO record
• As carrot for compliance with immediate treatment
• Prosecution a 6-month wait

• Sample : offenders whom the police have decided to prosecute, who are:
• Low risk offenders
• Who have no previous conviction (they may have previous cautions or other diversions)
• or one prior conviction (more than 5 years ago if an adult and 2 years ago if juvenile).
• And offence is not likely to result in instant prison sentence
• Randomly assigning them to prosecution or police offender management
• Developing and testing a standard protocol of tactics for police offender management

The Turning Point Experiment
Sample of 400 offenders whom the police have decided to prosecute
Random assignment=400
Prosecution = 200 Turning Point =200
Comparing like with like:
Measure Which has less crime? Cost?
, victim satisfaction

Turning Point Crime Types
N=205
Threatening words and
0%
0%
0%
0% behaviour/ harrassment
6%
Drugs
12%
Other
12%
Criminal
Damage
12%
Violent
26%
Property
32%

Imprisonment
1%
Costs etc. only
2%
Suspended
Imprisonment
3%
Community/
Referral
Order
28%
Fine
24%
Not Guilty/
Withdrawn/
Dismissed
25%
Conditional
Discharge
12%

Control v Treatment initial failures rates
Court nonappearance
25% v
Turning Point breach rates
25%

• If TPP can achieve same results or better
• At lower cost
• With no risk of increased harm
• Police have evidence for deciding not to prosecute
• Manage volume with legitimacy
• But only if Victims Believe in It

Birmingham Turning Point Hypotheses:
Drawing on past research:
• Victims will be happy with out of court disposals as long as they feel the police respect them, care about them, and are doing something in their interest
• How police explain the outcome will matter: reducing reoffending as a legitimate police goal
Molly Slothower

• 142 Victims of cases randomly assigned to proesecution or Turning Point over a 6month period
• 70% response rate in both TPP and prosecution
• Both conditions explained
• TPP description emphasized prevention, rehabilitation

“Satisfied” or “Very Satisfied”
46% increase for TPP

Turning Point sample was more likely to think what happened in their case is going to stop the offender from doing it again.
• …effect was not likely without attention to communication

Percent Victims Satisfied With Decision

• Paul Bartolomeo
• Successful experiment
• Voluntary Tagging
• Offenders after short prison
• Would not use
• Could not use
• Falsified Proof of Concept
• Useful Knowledge!

Harm Spots: Illegitimacy Hot Spots:
Cristobal Weinborn Alex Murray

Targeting Hot Spots:
Crime, Harm, Demand
• Counts of crime
• At same units of analysis
• Whether addresses, intersections, street segments
• Regardless of crime types selected
• All crimes are created equal?
• Showing probability of encountering any crime of that type (or types)

• Are all crimes created equal?
• Aren’t some more serious than others?
• Does the prescribed sentence length indicate it?
• Canada—Crime Severity Index (2009)
• Cambridge Crime Harm Index (2007)
39

• Prescribed penalties for crimes
• Common currency of days in prison
• Sentencing Guidelines,
• Any state; or a national average
• Each AND ALL crime types
• In each unit of analysis
• In the following graphics,
• Unit of analysis = street segments
• One street from one intersection to the next

• Hot Spots are less concentrated than harm spots—they cover more area of land
• Harm spots are taller than hot spots
• More of the harm in Birmingham is concentrated into less land than the same percentage of crime counts
• Police can target fewer places, less space, with for more harm reduction using harm spots than by using hot spots.

Inside Hot Spots:
Special SEBP Issue of ICJR article
• Slough
• Non-domestic indoor violence
• Houses of Multiple Occupation
• Simon Bowden, Thames Valley
• Violent crime 137 times higher in HMOs
• Than in non-HMO dwellings
• Most HMOs illegal

Hot Spots of Illegitimacy:
CT Humint and Survey Data

How can police target with information already collected on DV ?
• Best evidence to date:
Suffolk UK (pop.730k).
• Matthew Bland, Crime
Analyst
• Cambridge Mst thesis— brilliant job!
• Analysis of 36,000 DV police callouts between
2009 and 2014.
Matthew Bland

• Number of days imprisonment by offence type
• Multiply Number of offences X days in jail
• Not actual, but sentencing guideline
• Social judgement of seriousness of crime

• Half of all repeat offenders offended against multiple victims
• 30% of all repeat victims were victimised by more than one offender
• 80% of all CHI harm occurred in < 2% of all dyads
(412 of 24K cases)
• Over half (53%) of the cases contributing to this
80% had just one reported event.

Volume of Domestic Violence Couples by Serious Harm (Sentencing
Guideline Prison Days if Convicted)
Highest Harm
2% of Dyads
Medium
Harm 18%
Of dyads
Low Harm
80% of dyads

Does offence seriousness escalate over time?
• Most dyads show no escalation in CHI harm
• The tiny fraction who reach four callouts do show a sharp escalation in seriousness.

What we can learn about Targeting
Domestic Violence:
• Differentiate levels of harm
• Look for a “power few” that drive the total harm levels
• Target police resource allocation to do the most good with limited tools and time

• Stop treating DV as a ‘unitary’ phenomenon
• Recognise that:
– it covers a wide range of seriousness;
– some victims are repeatedly victimised;
– some offenders offend against multiple victims.
• Remembering that police can only act on reported incidents, we cannot assume these are the only incidents: multi-agency approaches needed to identify “hidden” cases before first, high-harm events?
• Think about ‘segmenting’ DV so that different policies and interventions can be applied for different kinds of case

of
Heather Strang
Cambridge University

• A story about segmenting complex behaviour -
• Differentiating levels of harm
• What works for whom?

Domestic Violence Couples by Crime
Harm Index (Sentencing Guideline
Prison Days ) Bland, 2015
Highest Harm
2% of Dyads
Medium
Harm 18%
Of dyads
Low Harm
80% of dyads

• Southampton CARA Project (Hants) –
– Low harm, high volume
• Bracknell Forest (Thames Valley) –
– Medium harm, repeat offending
• Merseyside –
– High harm, repeat offending

Southampton, Hampshire:
‘CARA’ conditional cautioning program
• Target is
– low-serious incidents (and strict CPS evidence test)
– Adult male offenders
– who admit the offence
– No violence preceding 2 years
– Spousal incidents only
• Victim indicates no safety risk through this disposal

Random Assignment:
Two Types of Caution
Good Behaviour Only
• 4 months
• No more Domestic Abuse
• Then no prosecution
• Criminal Record shows caution
Conditional Caution/ Workshops
• Held in a hotel by Hampton Trust
• Two Sessions
• 3 weeks apart
• Saturday mornings
• 3 hours each
• All-male group
• Discuss domestic abuse issues
• ‘Motivational’ techniques e.g. What would your kids say?
• Not directive
• Encourage understanding DA
• Final session: set a goal for DA
66

Cambridge
Heather Strang
Lawrence Sherman
Barak Ariel
HAMPSHIRE POLICE
Alex Marshall
Robin Jarman
Scott Chilton
Jo Rowland
Nicky Cornelius
Rob Braddock
Tony Rowlinson

• UK’s Longest-Running Police Experiment?
• 137 weeks and still randomizing cases
• 256 cases randomised to date via Cambridge
‘Randomiser
185 cases have at least 12 months reoffending data
• 96 Controls (Conditional Caution alone)
• 89 CARA cases (CC + Hampton Trust Workshop)

Post-RA DA Arrests (Prevalence)
20,8%
(20/96)
CONTROL
11,2%
(10/89)
WORKSHOP
RA

Post-RA DA Charges (Prevalence)
16,7%
(16/96)
CONTROL
RA
6,7%
(6/89)
WORKSHOP

Post-RA Non-DV Charges (Prevalence)
6,3%
(6/96)
CONTROL
RA
2,2%
(2/89)
WORKSHOP

Post-RA Non-DV Arrests (Prevalence)
7,3%
4,5%
(7/96)
CONTROL
RA
(4/89)
WORKSHOP

300
DV Charges Per 1,000 Offenders Post-
Random Assignment
250
200
150
100
50
0
Control Workshop

200
Non_DV Charges Per 1,000 Offenders
Post-Random Assignment
150
100
50
0
Control Workshop

300
DV Arrests Per 1,000 Offenders Post-
Random Assignment
250
200
150
100
50
0
Control Workshop

120
Non_DV Arrests Per 1,000 Offenders
Post-Random Assignment
100
80
60
40
20
0
Control Workshop

• To get the 256 cases so far randomly assigned,
5562 cases assessed for eligibility so far.
• In catchment area between 25 and 40 DA cases each week
• About 50% are charged and about 50% NFA.
• Caseflow averaging 1.86 cases per week.
• What needs to happen to get more noncharged cases? – and not just in Hampshire.

• Multi-agency services for both victims and offenders, but separately.
• Eligibility based on risk and frequency of calls
– the most persistent cases.
• At least 6 months post-RA reoffending data now available.

• Raw count of repeats similar for E and C but
• Major reduction in serious harm in E group after treatment but
• More harm in E group during treatment mainly more RO breaches – treatment effect?
• Results so far ambiguous but promising –
• Need more cases and more follow-up time.

Merseyside Police Experiment:
Chronic Offenders
• Police rank-ordered persistent DV offenders by frequency in callouts
• Selected ‘top 200’ offenders
• Randomly assigned 100 to experimental treatment:
• Police contact them, preferably face to face
• Inform them they are under close surveillance: any offence will be charged
• Close contact and monitoring of victims by DV women’s support group
• Outcome measure will be comparative DV reoffending

• Different Effects on
Different People
• Different N of priors
• Different Harm Levels
81

• British Transport Police EBP, Analysts Trained
• Western Australia Police—EBPU, 100 trained
• Durham Police—EBPU
• Trinidad & Tobago—500 trained out of 6,000
• Uruguay Police—300 trained

Professor Laurie Robinson, George Mason U.

Legitimacy, Procedural Justice, and
Police Body-Cams
Dr. Barak Ariel

Lawrence W. Sherman
Heather Strang
Cambridge University