Lecture 7: Risk assessment and management Flashcards
What impact does risk assessment make to individuals?
Can remove someone’s freedom for months / years on the basis of the outcome
OR
Can discharge people who go to sexually / violently assault members of the general public / kill themselves
What is receiver operating characteristics?
ROC: s a graphical plot that illustrates the diagnostic ability of a classifier system (in this case risk assessment) as its discrimination threshold is varied
It identifies hits, false positives, miss and correct rejections
How can ROC be used in analysis of risk assessment?
Can follow offenders for 2 years after being released and see if the risk assessment was correct
What are the issues of ROC in the analysis of risk assessment?
Almost impossible to measure people labelled as high risk - unethical to release them and see what they can do
What is the AUC?
Area under curve of the ROC
What do different ROC/ AUC scores mean for accuracy of risk assessment?
AUC = 0.5 chance performance
AUC = 1.0 perfect performance
AUC= 0.56 regarded as ‘weak’
AUC = 0.65 regarded as ‘moderate’
AUC = 0.71 regarded as ‘strong’
AUC= 0.90 regarded as best as we could do considering we don’t have perfect outcome measures
Limitations of using ROC as predictors?
Loses the quality of the event e.g how long / how quickly they were violent / the extent of the violence etc
Strengths of using ROC as predictors?
ROC is immune to baseline changes (e.g does not matter if it is rare or common event)
Keeps a continuous nature of assessment scale
What factors predict violence?
Previous violence
Unemployment
Poor relationships
Victims of abuse
Negative attitudes
Poor temper control
Issues of using previous violence as a predictor of future violence?
The majority of people receiving a risk assessment for violent behaviour have already committed a violent crime / act
What is an unstructured clinical judgment?
A professional looks at the available evidence, reads files, interviews and then pronounces on their view of how dangerous the person is
Based on their impression, intuition, gut feeling etc
What is the most widely used risk assessment method?
Unstructured clinical judgement
What are the strengths of unstructured clinical judgement?
- Allows ideographic analysis of offenders’ behaviour and a person and context-specific formulation that informs treatment, prevention, and management
What are the limitations of unstructured clinical judgement?
Allows biases
Overlooks important factors
Not based on empirical evidence of risks
What were psychiatrists previously told to assess in risk assessments?
Bedwetting
Cruelty to animals
Arson
Baxstrom study
Johnnie Baxstrom appealed at being detained in hospital for criminally insane after his sentence finished - the appeal was upheld and New York State decided that 966 other dangerous patients should also be released
Very few committed any offenses after being released - only 20 were later arrested for any violent crime (2% - only 20)
What do the results from the Baxstrom study suggest?
The decisions made by clinicians were hopeless
They were no more dangerous than other patients who were NOT allowed to be released
What do Gunn and Taylor (1993) say about the clinical judgment of future risk?
Whatever the theoretical position, in practice psychiatrists and others are bad at predicting the future violence of inmates released from institutions
Odeh et al (2006) study design
Gave professionals (inc nurses, psychologists, and psychiatrists) info about a patient and asked them to make various risk judgments and the probability and severity of future violence.
They were asked why they made the decisions
Odeh et al (2006) results
They found that the cues were not related to violence and therefore the inter-rater reliability was very poor
One said high risk, others low risk for the same person
Why are clinical judgments so bad?
- They are blind to their outcomes for the majority of cases - a smallish number of those released are violent and they may not hear about it - gives the impression they were right
- Tendency to weigh bizarre or unusual factors (e.g command hallucinations) heavily and neglect criminogenic factors
- Too many variables - research in cognitive psychology (Kahnemann and Tversky) reveals that we can only keep track of a small no. of variables when making decisions
- Tend to make judgments quickly and seek support for this
What is an actuarial assessment?
Factors thought to be predictive of risk are put together using a pre-ordained method and are normally based on a ‘construction sample’
What are the strengths of actuarial assessments?
Avoids individual bias
Does not need clinical skills to formulate
Fast
What are the weaknesses of actuarial assessments?
Often lacks ideographic information
Does not easily suggest risk management
A number is not enough
limited to questions given
person must fit with the sample
static measure - now show change in dangerousness
Describe the Quinsey et al (1998; 2006) study
Based on 618 men from Canadian maximum secure psychiatric unit - all had committed at least one serious antisocial act were released into:
- the community
- minimum security
- half way house
and followed for 10 years to see if they committed a violent act
How did Quinsey et al (1998; 2006) create the VRAG?
They measured a range of potential predictors e.g age, number of previous offenses etc)
Dropped any items that did not predict violence
If 2 items were very correlated (e.g the number of previous charges, the number of previous violent charges) the one with the highest correlation was used
Least-squared regression was used to see which of the remaining variables added independently to risk prediction mode
These 12 items were added to the VRAG
