Paul Zilly COMPAS sentencing risk assessment
In 2013, Paul Zilly was accused of stealing a push lawnmower and other tools in north Wisconsin. Zilly had long struggled with a meth habit and in 2012 he'd been working toward recovery with the help of a Christian pastor when he relapsed and committed the theft, according to an investigation by ProPublica.
Having scored as a high risk for violent recidivism by the Correctional Offender Management Profiling for Alternative Sanctions (COMPAS) tool, Zilly was sent to prison for two years and given three years of supervision, despite his lawyer agreeing to a plea deal with prosecutors in which the state would recommend one year in a county jail followed by supervision to ensure Zilly would 'stay on the right path.'
In his sentencing, Judge James Babler referenced the score generated by COMPAS, which calculated Zilly as high risk for future violent crime and medium risk for general recidivism. However, at an appeals hearing, Babler reduced Zilly's prison sentence to 18 months after he had heard testimony given by Northpointe CEO Tim Brennan, who said that he didn’t design his software to be used in sentencing and that his focus was on 'reducing crime rather than punishment.'
According to Judge Babler, he would have given a lower sentence. 'Had I not had the COMPAS, I believe it would likely be that I would have given one year, six months.' he said at the appeal.
Operator: Wisconsin Court System
Developer: Volaris Group/Equivant/Northpointe
Sector: Govt - justice
Purpose: Assess recidivism risk
Technology: Recidivism risk assessment system
Transparency: Governance; Black box
Rowe E.A., Prior N. (2022). Procuring Algorithmic Transparency (pdf)
Collins E. (2018). Punishing Risk (pdf)
Carlson A.M (2017). The Need for Transparency in the Age of Predictive Sentencing Algorithms (pdf)
Investigations, assessments, audits
ProPublica (2016). Machine Bias
News, commentary, analysis
Published: March 2023