Key Findings
Machine Learning Can Reduce Crime While Maintaining Release Rates
Algorithm-based decisions could reduce crime by 24.7% with no change in jailing rates, or reduce jail populations by 41.9% with no increase in crime rates.
Judges Miss High-Risk Cases
The riskiest 1% of defendants who judges release have a 56.3% failure-to-appear rate but are released 48.5% of the time.
Algorithm Reduces Racial Disparities
The algorithm can achieve the same crime reduction as judges while jailing 40.8% fewer minorities, demonstrating potential for both improved outcomes and increased equity.
Crime Reduction Potential Across Judge Leniency Quintiles
- Stricter judges (5th quintile) achieve 30.7% crime reduction but require 22.3% more jailing
- Algorithm could achieve same crime reduction with only 11.2% more jailing
- Shows efficiency gains possible through algorithmic decision-making
Racial Impact of Detention Decisions
- Algorithm achieves same crime rate while detaining 38.8% fewer Black defendants
- Hispanic detention rates reduced by 44.6%
- Demonstrates algorithm can improve both efficiency and equity
Risk Assessment Accuracy
- Algorithm identifies highest-risk 1% with 56.3% failure rate
- Judges release 48.5% of these high-risk defendants
- Shows potential for improved risk assessment through machine learning
Contribution and Implications
- Demonstrates practical value of machine learning in improving judicial decisions while reducing disparities
- Provides framework for evaluating algorithmic decision aids in presence of selective labels and multiple objectives
- Shows importance of considering both prediction accuracy and decision outcomes when implementing algorithmic tools
Data Sources
- Crime reduction comparison chart based on Table III showing relative performance across judge leniency quintiles
- Racial impact visualization derived from Table VII comparing detention rates by race between judges and algorithm
- Risk assessment accuracy chart constructed using data from Table II on algorithm's predictive performance