Flipping the Script on Criminal Justice Risk Assessment: An actuarial model for assessing the risk the federal sentencing system poses to defendants

TL;DR

This paper introduces a novel risk assessment tool that predicts the likelihood of defendants receiving excessively lengthy sentences based on legally irrelevant factors, highlighting systemic biases in the criminal justice system.

Contribution

It develops the first instrument to assess the risk to defendants from the justice system itself, using a two-stage model on federal sentencing data.

Findings

Achieves comparable accuracy to existing risk assessments

Identifies biases related to race and socio-demographics

Highlights limitations of current risk assessment tools

Abstract

In the criminal justice system, algorithmic risk assessment instruments are used to predict the risk a defendant poses to society; examples include the risk of recidivating or the risk of failing to appear at future court dates. However, defendants are also at risk of harm from the criminal justice system. To date, there exists no risk assessment instrument that considers the risk the system poses to the individual. We develop a risk assessment instrument that "flips the script." Using data about U.S. federal sentencing decisions, we build a risk assessment instrument that predicts the likelihood an individual will receive an especially lengthy sentence given factors that should be legally irrelevant to the sentencing decision. To do this, we develop a two-stage modeling approach. Our first-stage model is used to determine which sentences were "especially lengthy." We then use a second-stage model to predict the defendant's risk of receiving a sentence that is flagged as especially lengthy given factors that should be legally irrelevant. The factors that should be legally irrelevant include, for example, race, court location, and other socio-demographic information about the defendant. Our instrument achieves comparable predictive accuracy to risk assessment instruments used in pretrial and parole contexts. We discuss the limitations of our modeling approach and use the opportunity to highlight how traditional risk assessment instruments in various criminal justice settings also suffer from many of the same limitations and embedded value systems of their creators.