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Assessing Risk for Violence

Assessing Risk for Violence

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Assessing Risk for Violence

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  1. Assessing Risk for Violence Stephen D. Hart Simon Fraser University

  2. Violence • Actual, attempted, or threatened physical harm that is deliberate and nonconsenting • Includes violence against victims who cannot give full, informed consent • Includes fear-inducing behavior, where threats may be implicit or directed at third parties

  3. Violence as a Choice • The proximal cause of violence is a decision to act violently • The decision is influenced by a host of biological, psychological, and social factors • Neurological insult, hormonal abnormality • Psychosis, personality disorder • Exposure to violent models, attitudes that condone violence

  4. We Can’t Predict Violence… • Violence is too rare to predict with any accuracy, by any means • “Professional” decisions are particularly bad • Predictions of violence necessitate a deterministic view of behavior

  5. Or, Can We? • The issue of prediction is moot • Don’t predict, evaluate risk (e.g., suicide) • Regardless, predictions made by professionals are reliably better than chance • The scientific literature on violence is large and growing • Any choice can be predicted

  6. What is Risk Assessment? • Process of understanding a hazard to limit its potential negative impact • Hazard identification (which events occur?) • Hazard accounting (how frequently?) • Scenarios of exposure (under which conditions?) • Risk characterization (conditions present?) • Risk management (which interventions?)

  7. Nature of Violence Risk • Violence risk is a multi-faceted construct • Nature: what kinds of violence might occur? • Severity: how serious might the violence be? • Frequency: how often might violence occur? • Imminence: how soon might violence occur? • Likelihood: what is the probability that violence might occur?

  8. Risk is Context-Specific • We never know a person’s risk for violence; we merely estimate it assuming certain conditions • Assuming institutionalization, assuming release with supervision, assuming release without treatment for substance use… • Consequently, relative or conditional risk judgments are more useful than absolute or probabilistic risk judgments

  9. Goals of Risk Assessment • To make better decisions • Improve consistency • Protect public safety • Guide intervention • Protect clients’ rights • Liability management

  10. Risk CharacterizationContent Issues

  11. What to Include? • Three primary criteria • Empirical (predictive accuracy) • Professional (practical utility) • Legal (fairness and reasonableness)

  12. Problems With Empirical Criterion • Not everything that is important has been proven or validated scientifically • Can lead to exclusion of “good” but rare or difficult-to-assess risk factors • Prediction  cause, explanation, or intervention • Can lead to inclusion of “bad” but common or easy-to-assess factors

  13. Example: The SIEVE • Age Young is bad • Sex Male is bad • Facial hair Dense is bad • Foot size Big is bad

  14. Problems With Professional Criterion • Focus on dynamic factors may bias risk assessments • Can lead to exclusion of “good” but static or easy-to-ignore factors • Conventional wisdom of professionals may be plain wrong • Can lead to inclusion of “bad” but vivid or dramatic factors

  15. Example: Clinical Intuition • Depression Present is good • Anxiety Present is good • Intelligence High is good • Rorschach Seeing viscera is bad

  16. Problems With Legal Criterion • Useful for excluding risk factors, but not for including them • It can be argued that almost any risk factor is unfair or unreasonable in some respect

  17. Risk CharacterizationProcedural Issues

  18. Conventional Approaches • Professional judgment • Unstructured or “clinical” • Anamnestic (see Melton et al., 1997) • Structured (e.g., HCR-20, SVR-20) • Actuarial decision-making • Psychological tests (e.g., MMPI-2, PCL-R) • Risk scales (e.g., VRAG, RRASOR)

  19. Professional Judgment • Most commonly-used method for violence risk assessment • Familiar to professionals • Familiar to courts and tribunals • General strengths of method • Flexible (easy administration) • Requires limited training and technology • Person-centered (“idiographic”)

  20. Unstructured: Features • No constraints on evaluation • Any information can be considered • Information can be gathered in any manner • No constraints on decisions • Information can be weighted and combined in any manner • Results can be communicated in any manner

  21. Unstructured: Limitations • No systematic empirical support • Low agreement (unreliable) • Low accuracy (unvalidated) • Foundation is unclear (unimpeachable) • Relies on charismatic authority • Decisions are broad bandwidth • Focus is on culpability, not action

  22. Anamnestic: Features • Imposes minor structure on evaluation • Must consider, at a minimum, nature and context of past violence • Action-oriented • Logically related to development of risk management strategies • Consistent with “relapse prevention” or “harm reduction” approaches

  23. Anamnestic: Limitations • Unknown reliability • Unknown validity • Assumes that history will repeat itself • Violent careers are static • Violent people are specialists

  24. Structured: Features • Imposes major structure on evaluation • Must consider, at a minimum, a fixed and explicit set of risk factors • Specifies process for information-gathering • Imposes minor structure on decision • Specifies language for communicating findings • Action-oriented

  25. Structured: Limitations • Requires “retooling” of evaluation process • Systematized information-gathering • New training and technology • Justification for imposing structure requires inductive logic (faith) • What works elsewhere will work here • Professional discretion is appropriate

  26. HCR-20 • HCR-20, version 2 • Webster, Douglas, Eaves, & Hart (1997) • Designed to assess risk for violence in those with mental or personality disorders • 10 Historical, 5 Clinical, and 5 Risk Management factors

  27. Applications • Assess clinical evaluations of violence risk across a broad range of populations and settings • Civil and forensic psychiatric, correctional • Institution, community • Monitor clinical and situational factors that may be relevant to violence • Guide risk management strategies

  28. Conceptual Basis • Intended to bridge clinical and empirical domains and knowledge bases • Evidence-based risk assessment • Content determined rationally • Based on reviews of scientific and professional literatures • Not optimized on a particular sample

  29. Temporal Organization

  30. Previous violence Young age at first violence Relationship instability Employment problems Substance use problems Major mental illness Psychopathy Early maladjustment Personality disorder Prior supervision failure Historical Factors

  31. Lack of insight Negative attitudes Active symptoms of major mental illness Impulsivity Unresponsive to treatment Plans lack feasibility Exposure to destabilizers Lack of personal support Noncompliance with remediation attempts Stress Clinical & Risk Management Factors

  32. Actuarial Decision-Making • Commonly-used adjunctive method for violence risk assessment • Familiar to some professionals (psychologists) • Somewhat familiar to courts and tribunals • General strengths of method • Highly structured/systematic (“objective”) • Empirically-based (“scientific”)

  33. Psychological Tests: Features • Measure some disposition that predicts violence, according to past research • Reliability and validity of test-based decisions has been evaluated • Imposes major structure • On some part of the evaluation process • On some part of the decision-making process

  34. Psychological Tests: Limitations • Require professional judgment • Which tests to use • How to interpret scores • Justification of use requires inductive logic • Our population is like theirs • Our use of the test is like theirs

  35. PCL:SV • Symptom construct rating scale • requires clinical / expert judgment • based on “all data” • Data obtained from two primary sources: • review of case history (required) • interview / observation (recommended)

  36. Part 1 Superficial Grandiose Deceitful Lacks remorse Lacks empathy Doesn’t accept responsibility Part 2 Impulsive Poor behavioral controls Lacks goals Irresponsible Adolescent antisocial behavior Adult antisocial behavior PCL:SV:Items

  37. PCL: Summary #1 • The correlation between the PCL and violent recidivism averages about .35 • Regardless of length of follow-up • Even in sex offenders, forensic patients, women, delinquents — even in nonviolent, nonpsychopathic offenders • Association is quasi-linear (positive and monotonic)

  38. PCL: Summary #2 • Among psychopaths (e.g., PCL-R > 30) released from prison, the 5-year violent reoffense rate is about 70% • Versus about 30% in low group (< 20) and 50% in medium group (21-29) • Versus low group, psychopaths are at very high risk for reoffense (rate ratio = 2x to 3x; odds ratio = 5x to 10x)

  39. PCL: Summary #3 • Psychopaths not only commit more violence, they commit different kinds of violence • The violence of psychopaths often has unusual or atypical motivations • Instrumentality/gain • Impulsivity/opportunism • Sadism

  40. PCL: Conclusions • Psychopathy must be assessed as part of comprehensive violence risk assessments • The presence of psychopathy compels a conclusion of high risk • The absence of psychopathy does not compel a conclusion of low risk • Psychopathy must be assessed by trained professionals using adequate procedures

  41. Decision Tree Homicidal/suicidal? YES High Risk NO Sexual sadism? YES High Risk NO Psychopathic? (e.g., PCL-R > 30) YES High Risk NO Assess other factors (e.g., HCR-20)

  42. Risk Scales: Features • Designed solely to predict an outcome • High-fidelity • Optimized for specific outcome, time period, population, and context • Impose rigid structure • On all of the evaluation process • On all of the decision-making process

  43. Risk Scales: Limitations • Still require professional judgment • Which scales to use • How to interpret scores • Justification of use still requires induction • Our population is like theirs • Our use of the test is like theirs • Results may be easily misinterpreted • Pseudo-objective, pseudo-scientific

  44. VRAG • Violence Risk Appraisal Guide • Quinsey et al. (1998) • Constructed in adult male patients assessed or treated at a maximum security hospital • 12 items weighted according to ability to postdict violence over 7 year follow-up • Total scores divided into 9 bins, with estimated p(violence) from 0% to 100%

  45. PCL-R score Elem. school problems Personality disorder Age (—) Separated from parents under age 16 Failure on prior conditional release Nonviolent offense history Never married Schizophrenia (—) Victim injury (—) Alcohol abuse Female victim (—) VRAG Items

  46. VRAG: Potential Problems The VRAG is, in essence, a history lesson: • What if patient profile changes? • What if p (violence) changes? • What if the assessment context changes?

  47. VRAG: Actual Problems? • Paul Bernardo is a convicted serial murderer (3 sexual homicides) and serial rapist (75 known rapes) • Currently serving life imprisonment for murder, and an indeterminate sentence for the rapes • VRAG completed on the basis of case history data

  48. Bernardo’s VRAG Results • PCL-R score +4 • Elem. school… -1 • Personality disorder +3 • Age 0 • Separated from… -2 • Failure on prior… 0 • Nonviolent offense… -2 • Marital status -2 • Schizophrenia +1 • Victim injury -2 • Alcohol abuse +1 • Female victim -1 Total: -1 Bin #: 4 p(viol): 17% - 31%

  49. Problems With All • Focus on negative characteristics • “Sticky” labels • What about strengths (resources, “buffer” factors)? • Risk assessment ¹ risk management • What to do with high-risk individuals? • Quality control • Who will assess risk, and how?

  50. Risk References • Boer, 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. • Grove, 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, 293-323. • Kropp, 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. • Meehl, 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.)