Offender Assessment System

Part of a series on
Algocracy
Examples
AI in government LLMs in government Cybersyn DAO Digital dictatorship Merit order OGAS Education Ofqual exam results algorithm ChatGPT in education OIA PMPs Predictive policing Gangs Matrix VioGén Predictive sentencing COMPAS OASys OGRS Robodebt scheme Smart city Surveillance capitalism SyRI Tariffs in the second Trump administration
v t e

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Offender Assessment System" – news · newspapers · books · scholar · JSTOR (April 2025) (Learn how and when to remove this message)

OASys is the abbreviated term for the Offender Assessment System, used in England and Wales by His Majesty's Prison Service and the National Probation Service to measure the risks and needs of criminal offenders under their supervision. Initially developed in 2001, it was built upon the existing ‘What Works’ evidence base.^[1]

OASys is designed to enable a properly trained and qualified individual; often a Probation Officer, to:

• assess how likely an offender is to be re-convicted
• identify and classify offending-related needs, including basic personality characteristics and cognitive behavioural problems
• assess risk of serious harm, risks to the individual and other risks
• assist with management of risk of harm
• links the assessment to the supervision or sentence plan
• indicate the need for further specialist assessments
• measure change during the period of supervision / sentence.

OASys comprises a series of computer-based forms on which clinical evaluations are made by staff of Offenders, and supervision and sentence plans for the forthcoming period of supervision are recorded on a periodic basis - typically every 16 weeks for offenders in the community, and less frequently for imprisoned offenders.

OASys supports the What Works? initiative of the Prison and Probation Services, by providing metrics by which the characteristics of offenders and their offences (inputs) can be analysed alongside information on interventions made (inputs) to the offender, and re-conviction data for offenders (outcomes), in order to enable refinement to be made to interventions (based on a consideration of the relation between inputs and outcomes) as to improve outcomes - in other words, to decrease recidivism rates by ensuring that interventions are as appropriate and purposeful as possible.

• OASys: the new Offender Assessment System - National Probation Service, Spring 2003
• Findings from the measurement of OASys completion rates - Ministry of Justice, March 2009