Static-99 Assessment
Also known as: Static-99, Static-99R, Static 99, Static-99 Sexual Recidivism Risk Tool
Static-99, and its age-revised form Static-99R, is the most widely used actuarial instrument for estimating sexual and violent recidivism risk among adult male sexual offenders. It scores ten unchanging, historical risk factors into a total that maps onto a risk category and, via published norm tables, an estimated probability of reoffending — providing a standardized, evidence-based anchor for forensic risk decisions.
Key highlights
- Demonstrated predictive validity for sexual and violent recidivism across many independent cross-validation samples and countries.
- Brief, transparent, and inexpensive to score from official records, with detailed published coding rules.
- Provides norm-referenced recidivism estimates, letting evaluators communicate risk relative to a defined population.
- Static-99R's age re-weighting improved calibration, especially for older offenders whose risk declines with age.
- Serves as a widely accepted common metric, easing communication among clinicians, supervisors, and courts.
Intuition
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How it works
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When to use it
Use Static-99/Static-99R to establish a standardized, defensible baseline of long-term sexual recidivism risk for adult male sexual offenders in forensic, correctional, and civil-commitment contexts. It is appropriate when official records support reliable coding of the static items and when a transparent, actuarial anchor is needed for treatment planning, supervision, or court testimony. It is not appropriate for female offenders, juveniles, or offenders without a qualifying sexual offense, and it captures only static risk — dynamic risk and protective factors should be assessed with complementary tools (e.g., Stable/Acute-2007) before any high-stakes decision.
Strengths & limitations
- Demonstrated predictive validity for sexual and violent recidivism across many independent cross-validation samples and countries.
- Brief, transparent, and inexpensive to score from official records, with detailed published coding rules.
- Provides norm-referenced recidivism estimates, letting evaluators communicate risk relative to a defined population.
- Static-99R's age re-weighting improved calibration, especially for older offenders whose risk declines with age.
- Serves as a widely accepted common metric, easing communication among clinicians, supervisors, and courts.
- Uses only static factors, so it cannot register change from treatment, aging beyond the age item, or dynamic risk states.
- Validated specifically for adult male sexual offenders; it does not apply to women, juveniles, or non-sexual offenders.
- Absolute recidivism estimates depend heavily on the chosen reference sample and the base rate of the local setting.
- Group-level probabilities do not translate into a definitive prediction for any individual offender.
- Coding errors and outdated norm tables can materially shift the score and the implied risk, especially in adversarial settings.
Common pitfalls
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Applications
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Frequently asked
What is the difference between Static-99 and Static-99R?
Static-99R is a revision of Static-99 that re-weights the age-at-release item to better reflect the well-documented decline in sexual recidivism risk as offenders age, allowing older offenders to receive negative points. The other nine items are essentially unchanged. Static-99R, together with updated norm tables, is now the recommended version for most evaluations.
Does a Static-99 score predict whether a specific person will reoffend?
No. The score places an offender within a risk category and links to an estimated recidivism rate observed in a reference sample of similar offenders. It is a group-relative probability, not an individual certainty: it tells you how the person's risk compares to others and what proportion of similar people reoffended, which is why it should be reported with its reference sample and combined with other information.
Who can Static-99 be used on?
It is validated only for adult male sexual offenders who have at least one qualifying sexual offense and are being assessed at release to the community. It should not be applied to female offenders, juveniles, offenders whose index offense is not sexual, or to estimate risk for outcomes other than sexual and (for some norms) violent recidivism.
Sources
- 1.Hanson, R. K., & Thornton, D. (2000). Improving risk assessments for sex offenders: A comparison of three actuarial scales. Law and Human Behavior, 24(1), 119–136.
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Cite this page
ScholarGate. (2026, June 22). Static-99 Assessment. ScholarGate. https://scholargate.app/criminology/static-99-assessment