Pretrial RATs have had varying impacts on jail populations and the demographics of who is locked up or surveilled in the community pretrial.

Although these tools are often marketed as a way to reduce jail populations and overcrowding, they do not automatically decrease jail populations.

One systematic review of the impact of risk assessments on pretrial detention and release rates found that there is no strong evidence that RATs lead to significant reductions in incarceration. The researchers also stated, “it is unclear how tools impact racial and ethnic disparities in placements.”1Jodi L. Viljoen, Melissa R. Jonnson, Dana M. Cochrane, Lee M. Vargen, and Gina M. Vincent: Impact of Risk Assessment Instruments on Rates of Pretrial Detention, Postconviction Placements, and Release: A Systematic Review and Meta-Analysis, Law and Human Behavior

Most jurisdictions we spoke to do not gather enough data to say what the impact on their jail population was, meaning many places are adopting these tools without fully documenting their influence on decarceration. Some have not seen drops in their pretrial populations.

And even in places that have experienced decarceration alongside the implementation of RATs, given the complexity of policy changes and local context, as well as the varying impact RATs have on judicial decision-making, it can be difficult to attribute specific jail population changes to a RAT at all.

Plus, assessments of various types have been used in some pretrial settings for decades, without a clear intention of decreasing jail populations at all.

Learn more in the Pretrial Populations section.

Some of the jurisdictions we interviewed noted that tackling the racial disparity in jail populations was a key goal of their pretrial programs, while others did not feel that was their objective.

No jurisdiction that we interviewed could share with us any concrete data about the racial demographics of their jail population, making it difficult to support any claims that pretrial RATs decrease racial disparities. 

Read more about RATs’ racial impact in the Demographics section.