Flashcards in Lecture 10: Risk Assessment Deck (29):
Why should we care about risk assessment?
Because Risk assessment informs: Sentencing (especially Dangerous offender hearings), classification, treatment needs, treatment intensity, parole decisions, level of supervision, notification decisions, release conditions.
What is risk assessment?
A concept involving two components: (1) risk prediction - assessing the risk that people will commit violence in the future, and (2) risk management - developing effective intervention strategies to manage that risk.
What are the goals of risk assessment?
Improve accuracy (making correct decisions in regards to high or low risk)
Improve transparency (people like the offender, the victim, the public, need to understand why someone is released or not released)
Improve consistency (the same decisions should be made)
What is a true positive?
A correct prediction that occurs when a person who is predicted to engage in some type of behaviour (e.g., a violent act) does so
What is a true negative?
a correct prediction that occurs when a person who is predicted not to engage in some type of behaviour (e.g, a violent act) does not
What is a false positive?
an incorrect prediction that occurs when a person is predicted to engage in some type of behaviour (e.g., a violent act) but does not
what is a false negative?
An incorrect prediction that occurs when a person is predicted not to engage in some type of behaviour (e.g., a violent act) but does
How are the last two types (false negative and positive) dependant on each other?
Minimizing the number of false positive errors will result in an increase in the number of false negative errors.
What do we consider in risk assessments?
Risk factors- which are variables related to recidivism
What is risk management?
Develop effective intervention strategies to manage that risk
What are static risk factors?
Fixed and unchanging, Most convenient, Most frequently used, Can be reliably measured and are very predictive , If its historical or previous involvement like the commission of a crime or a history of mental illness it is static, because the past cannot be changed.
What are dynamic risk factors?
Change with time, Less convenient, less reliable, Less frequently used, BUT: sensitive to change. With intervention, can change level of risk
What are some examples of static risk factors?
Demographic variables (Being male is a static risk factor, men are more likely to reoffend), History of criminal behaviour, History of mental disorder
What are the 2 Main types of dynamic risk factors?
Stable dynamic: persistent and change slowly, if at all (e.g., impulse control, coping ability)
Acute dynamic: rapidly fluctuating (e.g., intoxication, personal support, employment)
What are the big 4 risk factors?
Procriminal personality (impulsive, aggressive)
What variables are commonly mistaken for risk factors?
Low Socioeconomic status (not an INDIVIDUAL risk factor for reoffending, may increase exposure to crime but is not a predictor for reoffending)
Personal distress/psychopathology (also includes low self esteem or depression
Fear of punishment
What are the 3 approaches to risk assessment?
Unstructured clinical judgement, actuarial prediction, and structured professional judgement
What is unstructured clinical judgement?
Decisions characterized by a substantial amount of professional discretion and lack of guidelines. Subjectively selecting what factors to look at, analyzing these factors and then interpreting the risk. This is usually a disaster
Advantages: very flexible (because you are not restricted by anything), idiographic (person specific, case by case basis)
Disadvantages: inconsistent, low accuracy
What is actuarial prediction?
Actuarial tools collect pre-specified risk factors that are entered into a statistical model that weights them, combines them, and produces a probability of offenders
Advantages: consistent and high accuracy
Disadvantages: Nomothetic, Validity across different samples (it will be low). Sometimes can be quite poor in making transparent decisions, that is, making decisions that people understand
What is an example of an actuarial tool?
The violence risk appraisal guide (VRAG). Consists of 12 weighted static risk factors. Added together to give overall probability of risk. Code presence of risk factors, Total the scores, Assign individual to 1 of 9 bins, Estimate probability of violence
What is structured professional Judgement?
Arising from the limitations associated with unstructured clinical judgement and concern that the actuarial method did not allow for individualized risk level, a new approach to risk assessment emerged. decisions are guided by a predetermined list of risk factors that have been selected from the research and professional literature (case specific details are added in as well). Judgement of risk level is based on the evaluators professional judgement.
Advantages: flexible, nomothetic-idiographic
Disadvantages: moderate accuracy (clinical judgement),less consistent than actuarial
What is an example of a structure professional judgement tool?
the HCR-20, in this approach the evaluator conducts a systematic risk assessment and refers to a list of risk factors, each having specific coding criteria and a demonstrated relationship with violent recidivism based on the existing professional and empirical literature. The HCR-20 stands for the list of 20 items organized into three main scales that align risk factors into past (historical), present (clinical) and future (risk management).
Low risk: monitor and intervene with low priority and intensity
Mid risk: monitor and intervene with some priority and intensity
High Risk: monitor and intervene with high priority and intensity
Why do we use tools to evaluate risk assessment tools?
Most important: predictive accuracy, Does it predict recidivism? Do the high risk offenders reoffend more than the low risk offenders?
Also: ease of use, is it easy to train people on, how much time does it take, construct validity, consistent (inter rater reliability),
What is the receiver operating characteristic (ROC)?
In this context it is a technique for measuring the accuracy of risk assessments by examining false positive and true positives across decision threshold
A true positive is a "hit". A false positive is a false alarm. False negative or a miss (predict something and then something else happens. True negative or correct rejection. Decision thresholds Or cut-off scores: scores range varies from 0-40 (e.g., 30 out of 40 is too high risk you wont be released). Compare prediction column to reality column (violent)
Desribe the ROC graph
For each possible cut-off value (score), plot false positive rate (X-axis) as function of true positive rate (y axis). Connect the dot and get a curve. We can then measure the area under that curve to get an overall measure of predictive accuracy. Ideally you want the hit rate to false alarm rate ratio to be very high
According to the ROC how accurate are the unstructured clinical judgement, the Actuarial tool and the structured professional judgement?
Clinical judgements: AUC=0.55
Actuarial tools: AUC=.68 to .80
Structured professional judgement: AUC= .62to .75
What is base rate?
represents the percentage of people within a given population who commit a criminal or violent act.
What is the base rate problem?
To predict violence we must determine base rates. But it is difficult to make accurate predictions when the base rate is too high or to low. A problem that emerges when attempting to predict events that have a low base rate is that many false positives will occur (e.g., the past decade has seen several high profile shootings, although they generate a lot of media coverage they are infrequent , any attempt to predict which youth might engage in school shooting would result in many people being wrongly classified). The general rule is that it is easier to predict frequent events than infrequent events.