Static-99

The Static-99, a 10-item checklist, is the most widely used actuarial rating method used to assess sexual violence risk based on static risk factors. In 1999, psychologists David Thornton and Don Grubin of the UK prison system combined the Rapid Risk Assessment for Sex Offence Recidivism (RRASOR) and Structured Anchored Clinical Judgment (SACJ- Min) to produce the Static-99. It was intended to be superseded by the Static-2002, but this never caught on. In September 2009, R. Karl Hanson introduced the Static-99R, which more precisely considered an offender's age at release. The Static-99 is often used in civil commitment proceedings.[1]

The risk factors in the Static-99 include presence of prior sexual offenses; having committed a current non-sexual violent crime; having a history of non-contact sex offenses; history of non-sexual violence; the number of prior sentencing dates on the criminal record; the age of the victim is less than 18 years old; having male victims; having unrelated victims; having victims who are strangers to the defendant; and having never lived with a lover for two continuous years. Possible scores include low risk, low to moderate risk, moderate to high risk, and high risk. An Iowa study found that the ISORA identifies twice as many low risk offenders as the Static-99, and that this larger does have a very low recidivism rate.[2]

The Static-99 is instrumental in most sexually violent predator determinations.

Criticism[edit] A study found, "Sexual recidivism rates for the same Static-99 score vary widely, from low to high, depending on the sample used." Another criticism is that the Static-99 purposefully ignores salient clinical factors, dismissing them as noise.[3] Another criticism is that the Static-99 overestimates risk of reoffending because the original group of Canadian and British criminals used to validate the test came from an earlier era in which sexual violence was more common than it is today.[1] A 10 March 2008 listserv communication from Hanson and Harris stated, "Recently, (we) found follow-up recidivism rates to be below that which would be expected given those found in the original STATIC-99 samples of origin. This has led to some question as to whether there has been a shift in the nature of sexual recidivism and whether the estimates generated from the samples of origin are still valid."

The Static-99, like most actuarial risk assessment instruments, it is only +/- 70% accurate. There are false positives, over-predicting risk, and false negatives, under-predicting risk. Over-reliance on unchanging static risk factors to the exclusion of changing dynamic risk factors is sometimes cited as a significant problem.

The Static-99, although appearing easy to score, has many scoring rules to understand, and an 80-page scoring manual.

References[edit] ^ Jump up to:Jump up to:a b These 10 Questions Can Mean Life Behind Bars Jump upJump up^ Statistical Validation of the ISORA8 & Static-99 Final Report Jump upJump up^ Shoba Sreenivasan, PhD, Linda E. Weinberger, PhD, Allen Frances, MD and Sarah Cusworth-Walker, PhD (September 2010). "Alice In Actuarial-Land: Through the Looking Glass of Changing Static-99 Norms". J Am Acad Psychiatry Law 38(3): 400–406. See also[edit] List of tools used in sex offender forensic psychological evaluations