Question to the Ministry of Justice:

To ask the Secretary of State for Justice, what assessment his Department has made of the effectiveness of the Offender Assessment System (OASys) in probation.

OASys is the core risk assessment tool for HMPPS and was built on the existing evidence base in the literature and piloted prior to its implementation in 2001. The intention was that, as the evidence base developed, the System would be improved over time. A continuing research programme has assisted in the development of OASys following implementation, helping to ensure that it remains a valid and reliable tool for assessing offenders’ risk.

The first OASys research compendium (Debdin, 2009) presented the findings from research and analysis completed between 2006 and 2009. This contributed to some important revisions to OASys: A compendium of research and analysis on the Offender Assessment System (OASys) 2006-2009 (cep-probation.org).

A second research compendium (Moore, 2015) presents the OASys studies completed between 2009 and 2013, including a systematic review of the underlying evidence base, a survey of assessors’ views and experiences, and analyses of various aspects of reliability and validity: A compendium of research and analysis on the Offender Assessment System (OASys), 2009–2013 (publishing.service.gov.uk).

The OASys Sexual reoffending Predictor was introduced after the compendium was written, and the evaluation of that tool is also available: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/955345/comparing-2-predictors-sexual-recidivism.pdf.