Presentation on theme: "Assessing Risk for Violence Stephen D. Hart Simon Fraser University."— Presentation transcript:
Assessing Risk for Violence Stephen D. Hart Simon Fraser University
Violence zActual, attempted, or threatened physical harm that is deliberate and nonconsenting yIncludes violence against victims who cannot give full, informed consent yIncludes fear-inducing behavior, where threats may be implicit or directed at third parties
Violence as a Choice zThe proximal cause of violence is a decision to act violently zThe decision is influenced by a host of biological, psychological, and social factors yNeurological insult, hormonal abnormality yPsychosis, personality disorder yExposure to violent models, attitudes that condone violence
We Can’t Predict Violence… zViolence is too rare to predict with any accuracy, by any means z“Professional” decisions are particularly bad zPredictions of violence necessitate a deterministic view of behavior
Or, Can We? zThe issue of prediction is moot yDon’t predict, evaluate risk (e.g., suicide) zRegardless, predictions made by professionals are reliably better than chance zThe scientific literature on violence is large and growing zAny choice can be predicted
What is Risk Assessment? zProcess of understanding a hazard to limit its potential negative impact yHazard identification (which events occur?) yHazard accounting (how frequently?) yScenarios of exposure (under which conditions?) yRisk characterization (conditions present?) yRisk management (which interventions?)
Nature of Violence Risk zViolence risk is a multi-faceted construct yNature: what kinds of violence might occur? ySeverity: how serious might the violence be? yFrequency: how often might violence occur? yImminence: how soon might violence occur? yLikelihood: what is the probability that violence might occur?
Risk is Context-Specific zWe never know a person’s risk for violence; we merely estimate it assuming certain conditions yAssuming institutionalization, assuming release with supervision, assuming release without treatment for substance use… zConsequently, relative or conditional risk judgments are more useful than absolute or probabilistic risk judgments
Goals of Risk Assessment zTo make better decisions yImprove consistency yProtect public safety yGuide intervention zProtect clients’ rights zLiability management
Risk Characterization Content Issues
What to Include? zThree primary criteria yEmpirical (predictive accuracy) yProfessional (practical utility) yLegal (fairness and reasonableness)
Problems With Empirical Criterion zNot everything that is important has been proven or validated scientifically yCan lead to exclusion of “good” but rare or difficult-to-assess risk factors zPrediction cause, explanation, or intervention yCan lead to inclusion of “bad” but common or easy-to-assess factors
Example: The SIEVE zAgeYoung is bad zSexMale is bad zFacial hairDense is bad zFoot sizeBig is bad
Problems With Professional Criterion zFocus on dynamic factors may bias risk assessments yCan lead to exclusion of “good” but static or easy-to-ignore factors zConventional wisdom of professionals may be plain wrong yCan lead to inclusion of “bad” but vivid or dramatic factors
Example: Clinical Intuition zDepressionPresent is good zAnxietyPresent is good zIntelligenceHigh is good zRorschachSeeing viscera is bad
Problems With Legal Criterion zUseful for excluding risk factors, but not for including them zIt can be argued that almost any risk factor is unfair or unreasonable in some respect
Risk Characterization Procedural Issues
Conventional Approaches zProfessional judgment yUnstructured or “clinical” yAnamnestic (see Melton et al., 1997) yStructured (e.g., HCR-20, SVR-20) zActuarial decision-making yPsychological tests (e.g., MMPI-2, PCL-R) yRisk scales (e.g., VRAG, RRASOR)
Professional Judgment zMost commonly-used method for violence risk assessment yFamiliar to professionals yFamiliar to courts and tribunals zGeneral strengths of method yFlexible (easy administration) yRequires limited training and technology yPerson-centered (“idiographic”)
Unstructured: Features zNo constraints on evaluation yAny information can be considered yInformation can be gathered in any manner zNo constraints on decisions yInformation can be weighted and combined in any manner yResults can be communicated in any manner
Unstructured: Limitations zNo systematic empirical support yLow agreement (unreliable) yLow accuracy (unvalidated) yFoundation is unclear (unimpeachable) zRelies on charismatic authority zDecisions are broad bandwidth zFocus is on culpability, not action
Anamnestic: Features zImposes minor structure on evaluation yMust consider, at a minimum, nature and context of past violence zAction-oriented yLogically related to development of risk management strategies yConsistent with “relapse prevention” or “harm reduction” approaches
Anamnestic: Limitations zUnknown reliability zUnknown validity zAssumes that history will repeat itself yViolent careers are static yViolent people are specialists
Structured: Features zImposes major structure on evaluation yMust consider, at a minimum, a fixed and explicit set of risk factors ySpecifies process for information-gathering zImposes minor structure on decision ySpecifies language for communicating findings zAction-oriented
Structured: Limitations zRequires “retooling” of evaluation process ySystematized information-gathering yNew training and technology zJustification for imposing structure requires inductive logic (faith) yWhat works elsewhere will work here yProfessional discretion is appropriate
HCR-20 zHCR-20, version 2 yWebster, Douglas, Eaves, & Hart (1997) yDesigned to assess risk for violence in those with mental or personality disorders y10 Historical, 5 Clinical, and 5 Risk Management factors
Applications zAssess clinical evaluations of violence risk across a broad range of populations and settings yCivil and forensic psychiatric, correctional yInstitution, community zMonitor clinical and situational factors that may be relevant to violence zGuide risk management strategies
Conceptual Basis zIntended to bridge clinical and empirical domains and knowledge bases yEvidence-based risk assessment zContent determined rationally yBased on reviews of scientific and professional literatures yNot optimized on a particular sample
Historical Factors zPrevious violence zYoung age at first violence zRelationship instability zEmployment problems zSubstance use problems z Major mental illness z Psychopathy z Early maladjustment z Personality disorder z Prior supervision failure
Clinical & Risk Management Factors zLack of insight zNegative attitudes zActive symptoms of major mental illness zImpulsivity zUnresponsive to treatment z Plans lack feasibility z Exposure to destabilizers z Lack of personal support z Noncompliance with remediation attempts z Stress
Actuarial Decision-Making zCommonly-used adjunctive method for violence risk assessment yFamiliar to some professionals (psychologists) ySomewhat familiar to courts and tribunals zGeneral strengths of method yHighly structured/systematic (“objective”) yEmpirically-based (“scientific”)
Psychological Tests: Features zMeasure some disposition that predicts violence, according to past research zReliability and validity of test-based decisions has been evaluated zImposes major structure yOn some part of the evaluation process yOn some part of the decision-making process
Psychological Tests: Limitations zRequire professional judgment yWhich tests to use yHow to interpret scores zJustification of use requires inductive logic yOur population is like theirs yOur use of the test is like theirs
PCL:SV zSymptom construct rating scale yrequires clinical / expert judgment ybased on “all data” zData obtained from two primary sources: yreview of case history (required) yinterview / observation (recommended)
PCL:SV: Items Part 1 zSuperficial zGrandiose zDeceitful zLacks remorse zLacks empathy zDoesn’t accept responsibility Part 2 z Impulsive z Poor behavioral controls z Lacks goals z Irresponsible z Adolescent antisocial behavior z Adult antisocial behavior
PCL: Summary #1 zThe correlation between the PCL and violent recidivism averages about.35 yRegardless of length of follow-up yEven in sex offenders, forensic patients, women, delinquents — even in nonviolent, nonpsychopathic offenders yAssociation is quasi-linear (positive and monotonic)
PCL: Summary #2 zAmong psychopaths (e.g., PCL-R > 30) released from prison, the 5-year violent reoffense rate is about 70% yVersus about 30% in low group (< 20) and 50% in medium group (21-29) yVersus low group, psychopaths are at very high risk for reoffense (rate ratio = 2x to 3x; odds ratio = 5x to 10x)
PCL: Summary #3 zPsychopaths not only commit more violence, they commit different kinds of violence zThe violence of psychopaths often has unusual or atypical motivations yInstrumentality/gain yImpulsivity/opportunism ySadism
PCL: Conclusions zPsychopathy must be assessed as part of comprehensive violence risk assessments zThe presence of psychopathy compels a conclusion of high risk zThe absence of psychopathy does not compel a conclusion of low risk zPsychopathy must be assessed by trained professionals using adequate procedures
Decision Tree Homicidal/suicidal? NO YES High Risk Psychopathic? (e.g., PCL-R > 30) NO High Risk Assess other factors (e.g., HCR-20) Sexual sadism? NO High Risk YES
Risk Scales: Features zDesigned solely to predict an outcome zHigh-fidelity yOptimized for specific outcome, time period, population, and context zImpose rigid structure yOn all of the evaluation process yOn all of the decision-making process
Risk Scales: Limitations zStill require professional judgment yWhich scales to use yHow to interpret scores zJustification of use still requires induction yOur population is like theirs yOur use of the test is like theirs zResults may be easily misinterpreted yPseudo-objective, pseudo-scientific
VRAG zViolence Risk Appraisal Guide yQuinsey et al. (1998) yConstructed in adult male patients assessed or treated at a maximum security hospital y12 items weighted according to ability to postdict violence over 7 year follow-up yTotal scores divided into 9 bins, with estimated p(violence) from 0% to 100%
VRAG Items zPCL-R score zElem. school problems zPersonality disorder zAge (—) zSeparated from parents under age 16 zFailure on prior conditional release z Nonviolent offense history z Never married z Schizophrenia (—) z Victim injury (—) z Alcohol abuse z Female victim (—)
VRAG: Potential Problems The VRAG is, in essence, a history lesson: zWhat if patient profile changes? zWhat if p (violence) changes? zWhat if the assessment context changes?
VRAG: Actual Problems? zPaul Bernardo is a convicted serial murderer (3 sexual homicides) and serial rapist (75 known rapes) zCurrently serving life imprisonment for murder, and an indeterminate sentence for the rapes zVRAG completed on the basis of case history data
Problems With All zFocus on negative characteristics y“Sticky” labels yWhat about strengths (resources, “buffer” factors)? Risk assessment risk management yWhat to do with high-risk individuals? zQuality control yWho will assess risk, and how?
Risk References zBoer, D. P., Hart, S. D., Kropp, P. R., & Webster, C. D. (1997). Manual for the Sexual Violence Risk-20: Professional guidelines for assessing risk of sexual violence. Burnaby, British Columbia: Simon Fraser University. zGrove, W. M., & Meehl, P. E. (1996). Comparative efficiency of informal (subjective, impressionistic) and formal (mechanical, algorithmic) prediction procedures: The clinical-statistical controversy. Psychology, Public Policy, and Law, 2, zKropp, P. R., Hart, S. D., Webster, C.W., & Eaves, D. (1995). Manual for the Spousal Assault Risk Assessment Guide, 2nd ed. Vancouver, BC: British Columbia Institute on Family Violence. zMeehl, P. E. (1996). Clinical versus statistical prediction: A theoretical analysis and a review of the literature. Northvale, NJ: Jason Aronson. (Original work published in 1954.)
Risk References (cont.) zMelton, G. B., Petrila, J., Poythress, N. G., & Slobogin, C. (1997). Psychological evaluations for the courts: A handbook for mental health professionals and lawyers (2 nd ed.). New York: Guilford. zQuinsey, V. L., Rice, M. E., Harris, G. T., & Cormier, C. (1998). Violent offenders: Appraising and managing risk. Washington, DC: American Psychological Association. zWebster, C. D., Douglas, K. S., Eaves, D., & Hart, S. D. (1997). HCR-20: Assessing risk for violence, version 2. Burnaby, British Columbia: Simon Fraser University.
But How Accurate Are Characterizations of Risk?
A Complex Phenomenon zStudying the accuracy of risk characterizations is difficult due to the complexity of… yThe characterizations yThe violence yThe follow-up yIndexes of accuracy
The Characterizations zEvaluator: Professional vs. researcher; novice versus expert zProcess: Clinical vs. actuarial, contextual vs. context-free zTiming: Admission vs. discharge, static vs. dynamic zMetric: Uni- vs. multi-dimensional, categorical vs. continuous
The Violence zDirection: Self vs. others, acquaintances vs. strangers zNature: Instrumental vs. reactive zSeverity: Threats vs. battery vs. homicide zFrequency: Single vs. multiple events zContext: Situational precipitants or co- factors
The Follow-Up zData source: Patient vs. collaterals vs. records zTime at risk: Weeks vs. months vs. years zInterventions: Dynamic factors, life events zMonitoring: Continuous vs. endpoint
Indexes of Accuracy zComparison group: Other patients vs. normals zStatistic: Uni- vs. multi-variate, time zWeighting of errors: Equal vs. differential zInterpretation: Chance vs. status quo vs. perfection
Example (cont.) zIn this study... yAccuracy of positive predictions is 77% yAccuracy of negative predictions is 79% yOverall accuracy is 78% yChance-corrected agreement is 53% yCorrelation is.53 yOdds ratio is 12.5
Example (cont.) zSo, how did we do? yRelative to chance: Great! yRelative to perfection: Awful! yRelative to the status quo: ???
What is the status quo? zPredictions of violence using the PCL-R typically have an effect size (r) of about.35; the average effect size for psychosis is about.30 zAn effect size of.40 may be the “forensic sound barrier” zBut what is the status quo in other human endeavors?
Meta-Meta-Analysis zLipsey & Wilson (1993) reviewed 302 meta-analyses zDetermined typical effect sizes for psychological, educational, and medical interventions
Psychological Interventions zCBT — depression.44 zPsychotherapy — any .39 zCorrectional programs (youths).23 — any zDiversion (youths) — recidivism.20 zCorrectional treatment (adults).12 — any
Conclusions zViolence predictions, on the whole, are just as good as most other human prognostications zConsider other fields... yStock analysts yMeteorologists yFire inspectors yStructural engineers
Risk Assessment: Reports and Testimony
General Issues zAcknowledge professional qualifications yBut, less important than approach used zAcknowledge limits of information base yBut, comprehensiveness depends on context zExplain risk factors considered yEmpirical, professional, legal justification zAcknowledge uncertainty of “predictions”
Do Don’t zUse multiple approaches zMake relative or conditional risk judgments zMake detailed risk management recommendations z Rely on a single approach z Make absolute or probabilistic risk judgments z Ignore the issue of what can or should be done
Special Issues: Professional zReport should tell a story ySummarize the circumstances of past violence and any recent changes in them yDescribe the likely nature and context (scenarios) of future violence yIdentify factors that may increase risk and therefore serve as flags for re-assessment yRecommend, evaluate, and prioritize risk management strategies
Cross-Exam: Professional zWhat, if any, is the basis of your expertise in the assessment of violence risk? zWhat is the scientific basis for your decision (not) to follow these procedures? zWhat is the scientific basis for your decision (not) to consider these factors? zCan you state with any reasonable degree of scientific certainty the likelihood that X will be violent?
Special Issues: Actuarial zReport should provide full interpretation of test scores yBe familiar with research supporting the test’s reliability and validity yDiscuss general limitations of the test yDiscuss limitations of the test in this case
Cross-Exam: Actuarial zIsn’t it arbitrary to consider risk factors such as A, B, and C, but to ignore D, E, and F? zIs there any scientific evidence that scale Z predicts outcome Y in patients at this clinic? zHow do you know that predictions using scale Z are accurate for Mr. X? zBy using scale Z, aren’t you simply relying on statistical profile evidence?
Contact Information zStephen D. Hart, Ph.D. Department of Psychology Simon Fraser University Burnaby, British Columbia Canada V5A 1S6 Tel: / Fax: URL: