1.5 OASys is a risk and needs assessment tool. A new assessment system was developed because none of the existing tools and inventories fully met the requirements for consistent assessment to help practitioners make sound and defensible decisions. OASys contributes towards ensuring security and control through the identification and management of risk. OASys identifies and classifies offending related needs, such as a lack of accommodation, poor educational and employment skills, substance misuse, relationship problems, and problems with thinking and attitudes. It also assesses the risk of harm offenders pose to themselves and others. From these assessments, sentence plans are drawn up within OASys to manage and reduce these risks. Thereby, OASys will help target interventions, making them more effective, and contribute towards reducing re-offending and protecting the public.