Actuarial instruments a. Risk Matrix 2000 (for sexual and violent offenders: predicts risk of sexual, or violent reoffending, or either) Structured anchored clinical judgements
Actuarials: the Risk Matrix 2000 The Risk Matrix 2000 exists in three versions, predicting violence, sexual offending, or both. It uses a small number of items relating to offence history, age on release and type of victims. The matrix was developed on a sample of prisoners released in the late 1970s and followed up over 20 years. It places an individual in one of four risk bands (low, medium, high, very high). The titles of these risk bands may seem a little odd to a lay person, who might (for example) expect a high risk individual to be more likely than not to convict for further sexual offences, whereas the opposite is the case. Problems with the Risk Matrix 2000 a. Reconviction rates for sex offenders (at least) have reduced since the 1970s; the effect is to exaggerate risk in modern offenders.
b. It doesn’t take age into account past 35, but age-related risk reduction (which is very large) mostly takes place after this; again, the effect is to exaggerate risk. c. Hart (2005) showed it is more likely than not to place people in the right risk category, but only marginally so; the effect is to increase error. d. It has not been standardised on lifers, to whom it is mostly applied; the effect is anyone’s guess. e. It doesn’t distinguish between imminent risk and remote risk (it predicts over a 20-year period); remote prediction cannot in principle be accurate. Actuarials: the Static-99 (or 2002?) The Static-99 uses a similar method to the Risk Matrix 2000; the two have one author in common (David Thornton). An updated scoring system was produced in 2002/3, which tries to take additional factors into account, including reduction in risk because of offence-free time (ie, risk is less if there are no recent offences). In practice, many of the recommendations made in connection with this scoring are not supported by empirical research. In other words, there is a large element of the authors' opinion in the scoring scheme, and we still await scientific evidence on how good the authors' opinion actually is. As with the Risk Matrix 2000, the Static-99 uses items relating to age, victim, and offence history. Problems with the Static-99
Actuarials: the VRAG and SORAG These are the Violence Risk Assessment Guide and Sex Offender Risk Assessment Guide (Quinsey, Harris, Rice and Cormier, 2006). They are considered together because they use exactly the same rationale, and were devised by the same research group. They follow a similar rationale to the Risk Matrix 2000 and Static-99, but use more items, including some personality and mental health items, such as the PCL-R. Both were originally developed on forensic psychiatric patients in Canada, and this may affect their applicability to prisoners in the UK. Compared with the Risk Matrix and the Static, they give age more weight, though still not enough, failing to allow for any increase in age beyond 35 years. Both allot people to risk categories, resulting in predictions over 7 years and 10 years. The SORAG, although intended for sex offenders, actually predicts the risk of violent reoffending. The authors class all sexual offending as violent in some sense. Problems with the VRAG and SORAG
Actuarials generally: verdict
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