forensic psychology: risk assessment
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Risk Assessment
12 - 1
What is Risk Assessment?
Risk is viewed as a range (Steadman,
2000)
Probabilities change across time
Interaction among offender
characteristics and situation
Risk Assessment has 2 components:
Prediction
Management
12 - 2
Risk Assessments: Civil Settings
Civil commitment
Child protection
Immigration laws
School and labour regulations
Duty to warn & limits of confidentiality
W. v. Egdell (1990) (UK)
Tarasoff case (1974) (US)
12 - 3
Risk Assessments: Criminal
Settings
Risk assessments conducted at major
decision points:
Pretrial
Sentencing
Release
Public safety outweighs solicitor-client
privilege
Smith v. Jones
12 - 4
Predictions:
Decisions Versus Outcomes
DECISION Reoffends Does not
reoffend
Predicted to
reoffend
True positive
(correct)
False positive
(incorrect)
Predicted to
not reoffend
False negative
(incorrect)
True negative
(correct)
OUTCOME
5
Base Rates
Represents the % of people within a
given population who commit a criminal
or violent act
Accurate prediction difficult when
base rates are too high or low
False positives tend to occur with low
base rates
Easier to predict frequent vs. infrequent
events
12 - 6
Methodological Issues
Assumptions of risk assessment and
measurement
Ideal evaluation vs. reality
Three weaknesses of research (Monahan &
Steadman, 1994):
Limited number of risk factors
How criterion variable is measured
How criterion variable is defined
12 - 7
Other Methodological Challenges
Measuring recidivism
1. Problems with outcome measures
2. Length of outcome period
3. Categories of offenders
8
Judgment Error and Biases
Heuristics
Illusory correlation
Ignore base rates
Reliance on salient or unique cues
Overconfidence in judgements
Role of gender
12 - 9
Unstructured Clinical Judgment
Decisions characterized by professional
discretion and lack of guidelines
Subjective
No specific risk factors
No rules about how risk decisions should
be made
12 - 10
Dr. James Grigson
Nicknamed “Dr. Death” or “the hanging
shrink”
Forensic psychiatrist in Dallas
Used unstructured clinical judgment
Expelled from professional
association for claims of 100%
accuracy in predicting violence
12 - 11
Measuring Accuracy of
Dangerousness Predictions
Ultimate Outcome
Clinician’s predictions Homicide No Homicide
Homicide 8 (True Positives) 1,998 (False Positives)
No Homicide 2 (False Negatives) 7,992 (True negatives)
12 - 12
Actuarial Prediction
Decisions based on risk factors that are
selected and combined based on empirical
or statistical evidence
Evidence favours actuarial assessments
over unstructured clinical judgment
12 - 13
Static-99-R – An Actuarial
Measure young
have not lived with a lover for 2+ years
index-non-sexual violence
previous nonsexual violence
number of previous sentencing dates
previous sexual offences
physical harm to victim during sex offence(s), or use of weapon or
threats
any non-contact sex offences
any unrelated victims
any stranger victims
any male victims
14 14
Actuarial vs. Clinical Judgment Source # of
studies
Variables Predicted Clinical
Better
Statistical
Better
Tie
Grove et al.
(2000)
136 Success in
school/military;
recidivism; recovery from
psychosis; personality; tx
outcome; dx; job success
and satisfaction; medical
dx; marital satisfaction
8 63 65
Ægisdóttir et
al. (2006)
51 Brain impairment;
personality; length of
stay; dx; adjustment or
prognosis; violence; IQ;
academic performance;
suicide risk; sexual
orientation; MMPI – real
or fake
5 25 18
12 - 15
Structured Professional Judgment
Decisions guided by predetermined list of
risk factors derived from research
literature
Judgement of risk level is based on
professional judgement
Diverse group of professionals
12 - 16
Types of Predictors
Static Risk Factors
Historical
Factors that cannot be changed
Dynamic Risk Factors
Fluctuate over time
Factors that can be changed
Acute vs. stable dynamic risk factors
12 - 17
Important Risk Factors
Dispositional
Historical
Clinical
Contextual
12 - 18
HCR-20 Historical items
1. Previous violence
2. Young age at first violent incident
3. Relationship instability
4. Employment problems
5. Substance use problems
6. Major mental illness
7. Psychopathy
8. Early maladjustment
9. Personality disorder
10. Prior supervision failure
19 19
HCR-20
Clinical items
1. Lack of insight
2. Negative attitudes
3. Active symptoms of major mental illness
4. Impulsivity
5. Unresponsive to treatment
20 20
HCR-20
Risk management items
1. Plans lack feasibility
2. Exposure to destabilizers
3. Lack of personal support
4. Noncompliance with remediation attempts
5. Stress
21 21
Current Issues
Protective factors
Factors that reduce or mitigate the
likelihood of violence
Use of scientific research
Practitioners not using instruments
Where is the theory?
More attention on WHY is needed
12 - 22
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