Pretrial Risk Assessment Tool (Arnold Foundation)

Summary

The Arnold Foundation's Public Safety Assessment provides judges with algorithmic flight risk and new-crime risk scores to inform bail decisions. Implementation evaluations have produced mixed results: some jurisdictions achieved meaningful detention reductions, others did not. A consistent finding is that judges use the tool selectively — anchoring on high-risk scores more than low-risk scores — which can widen racial disparities rather than narrow them if not implemented carefully. The tool is now one of the most debated algorithmic interventions in public policy.

Research question

"Does providing judges with algorithmic risk scores at arraignment reduce pretrial detention without increasing failure to appear or rearrest?"

Methodology

Result

Mixed

Mixed: some jurisdictions reduced detention without increasing FTA; others saw no change or increased detention of low-risk defendants

Evidence strength

Moderate

Quasi-experimental design; causal interpretation requires care.

Replication status

Partially replicated