Evidence and Liberty: The Promise of Experimental Criminology

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Evidence and LibertyThe Promise of
Experimental Criminology

• Lawrence W. Sherman
• Wolfson Professor of Criminology
• Director
• Jerry Lee Centre for Experimental Criminology
• Institute of Criminology
• Cambridge University

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OUR PURPOSEJerry Lee Centre of Experimental
Criminology

• Advancement of human liberty
• on the basis of
• Experimental Evidence

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Evidence and Liberty

• You will know
• the truth, and the
• truth will set you free
• John 832.

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1781 Property Overboard?
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The 1785 Latin Prize

• Anne Liceat Invitos in Servitutem Dare?
• (Is it lawful to make
• slaves of others
• against their will?)

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Evidence Giant

• Thomas Clarkson

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Wades Mill, Herts.
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Sugar Boycott 1791
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(No Transcript)
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• Abu
• Ghraib
• Prison

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7 RCT Tests of A Drug on Infant Mortality
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From Joanna Shapland, et al, 2008, p. 27Effects
of Restorative Justice on Re-Conviction
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Did Program Cause Crime Drop?
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Randomized Controlled Trial RCTCOMPARISON or
NET difference
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From Joanna Shapland, et al, 2008, p. 27Effects
of Restorative Justice on Re-Conviction
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Early Release From Prison
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Fortune-Tellers
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Fortune-Tellers

• Not Experimentally
• Proven

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Crown Court Sentences

• Not Experimentally Proven

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Three Hardest Words

• I Dont Know.

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Evidence Into action

• Bottom-up Discretion
• Top-Down Guidance

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Bottom-Up Discretion
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Top-Down Guidance
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From Joanna Shapland, et al, 2008, p. 27Effects
of Restorative Justice on Re-Conviction
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List of Studies Included

• Offender N
• 1. Australia RISE Canberra lt30 years violence
  100
• 2. Australia RISE Canberra juvenile personal
  property 249
• 3. Australia RISE Canberra juvenile
  shoplifting 142
• 4. Australia RISE Canberra Driving Under
  Influence 897
• 5. US Indianapolis juvenile property/violence
  782
• 6. US Bethlehem PA juvenile property 143
• 7. US Bethlehem PA juvenile violence
  79
• 8. UK Northumbria juvenile property/violence
  208
• 9. UK Northumbria adult property 63
• 10. UK Northumbria adult assault
  44
• 11. UK London robbery 88
• 12. UK London burglary 167
• 13. UK Thames Valley violence probation 64
• 14. UK Thames Valley violence prison 94
• Total offender N 3,120

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Conventional Wisdom

• RJ is best for less serious crime
• Inappropriate for violence
• RJ is best for children (under 18)
• Inappropriate for Adults

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RESULTS

• 2-Year Reconvictions
• (Standard UK criterion for success)
• Frequency
• Prevalence
• Cost

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First Question

• In general, what effect does
• Face-to-face RJ meetings have on
• frequency of reconvictions, across
• different points of criminal justice process
• with personal victims intended to be there?
• ANSWER 9 out of 10 tests show less crime

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Personal Victims Change in Reconviction
Frequency
per person, RJ Group compared with Control Group
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Question 2

• What Effect Does RJ have on
• Frequency of Reconviction
• All tests
• 10 with victims present
• 2 not victims present
• Answer 10 out of 12 show less frequency
• Not one increase in UK (Australia only)

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Percent Change in the Frequency of Reconviction
per person, RJ Group compared with Control Group
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Question 3

• What effect does Face-to-face RJ have on
• Frequency of Reconviction
• In Violent Crime Experiments
• Youth and Adult Combined
• Answer 5 out of 5 violence tests show less crime

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Percent Change in the Frequency of Reconviction
Violence Exps
per person, RJ Group compared with Control Group
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Question 4

• What Effect Does RJ have on
• Frequency of Reconviction on
• Property Crime Offenders
• Youth and Adult Combined
• Answer 3 out 4 tests show less crime
• Effects not as big, or as prevalent, as for
  violence
• RJ WORKS BETTER FOR MORE SERIOUS CRIME

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Percent Change in the Frequency of Reconviction
Property Exps
per person, RJ Group compared with Control Group
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Question 5

• What Effect Does Face-to-Face RJ Have on
• Youth Crime
• Property and Violent
• US, UK, Australia?
• Answer 3 out of 4 tests show less crime

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Percent Change in the Frequency of Reconviction
Youth Exps
per person, RJ Group compared with Control Group
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Question 6

• What Effect Does Face-to-Face RJ Have on
• Adult Crime
• Property and Violent
• US, UK, Australia?
• Answer
• 6 out of 6 tests on adults less crime
• Effects bigger than for juveniles

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Percent Change in the Frequency of Reconviction
Adult Exps
per person, RJ Group compared with Control Group
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Question 7

• Does Face-to-Face RJ Reduce frequency of
  reconviction more when developers do their own
  evaluation, or when someone else evaluates the RJ
  conferences in a randomized trial?
• ANSWER Bigger effects with independent
  evaluators!

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Percent Change Reconviction FrequencyOur Own
Tests
per person, RJ Group compared with Control Group
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Change Reconviction FrequencyIndependent
Evaluators
per person, RJ Group compared with Control Group
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Yes, Minister

• --All policies decided at
• Highest levels
• --More politics
• --Less evidence?

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A NICE Approach

• National Institute for
• Health and Clinical
• Excellence

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NICE Hypertension Guidance
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Hot Spots of Crime

• (Density Distribution of Violent Offenses in
  Tokyo)

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A NICE, NPIA (?) Approach

• National Policing
• Improvement Agency

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Koper Curve
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Algorithm for Hot Spot Patrol

1. Define Hot Spots
2. Identify Locations
3. Add Extra Police Patrols
4. Make All Patrols Unpredictable
5. Stay 11-14 minutes Only
6. Add extra patrol if crime persists

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Evidence-Based Policing
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From Evidence to Liberty

• 1.Identify key questions

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From Evidence to Liberty

• 1.Identify key questions
• 2. Formulate testable hypotheses

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From Evidence to Liberty

• 1.Identify key questions
• 2. Formulate testable hypotheses
• 3. Conduct randomized experiments

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From Evidence to Liberty

• 1.Identify key questions
• 2. Formulate testable hypotheses
• 3. Conduct randomized experiments
• 4. Conduct quasi-experiments

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From Evidence to Liberty

• 1.Identify key questions
• 2. Formulate testable hypotheses
• 3. Conduct randomized experiments
• 4. Conduct quasi-experiments
• 5. Identify all good evidence

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From Evidence to Liberty

• 6. Synthesize in META-ANALYSIS

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From Evidence to Liberty

• 6. Synthesize in META-ANALYSIS
• 7. Present to small expert groups

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From Evidence to Liberty

• 6. Synthesize in META-ANALYSIS
• 7. Present research to small expert groups
• 8. Develop succinct guidance

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From Evidence to Liberty

• 6. Synthesize in META-ANALYSIS
• 7. Present research to small expert groups
• 8. Develop succinct guidance
• 9. Communicate or promulgate the guidance

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From Evidence to Liberty

• 6. Synthesize in META-ANALYSIS
• 7. Present research to small expert groups
• 8. Develop succinct guidance
• 9. Communicate or promulgate the guidance
• 10. Test Methods for compliance

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Prospective Meta-AnalysisBy A
REX-NetRandomized Experiments Network
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The Promise of Experimental Criminology

• The advancement of
• human liberty on the
• basis of experimental
• evidence

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Evidence and LibertyThe Promise of
Experimental Criminology

• Lawrence W. Sherman
• Wolfson Professor of Criminology
• Director
• Jerry Lee Centre for Experimental Criminology
• Institute of Criminology
• Cambridge University