I have noted before the work by former New Jersey AG Anne Milgram at the Arnold Foundation to bring evidence-based systems to the criminal justice system. Applying what she calls “moneyball” to criminal justice, rather than creating a strict “redemption period” as noted by Profs. Blumstein and Nakamara, Milgram build a risk assessment tool to enable judges to determine

whether, when someone has been arrested, whether they pose a risk to public safety and should be detained, or whether they don’t pose a risk to public safety and should be released. Everything that happens in criminal cases comes out of this one decision. It impacts everything. It impacts sentencing. It impacts whether someone gets drug treatment. It impacts crime and violence.

I mention all this as background to highlight a public back-and-forth between over the use of evidence-based systems in the criminal justice system. Milgram published a rebuttal, To Minimize Injustice, Use Big Data to a New York Times op-ed, Sentencing by the Numbers, written by Sonja B. Starr the co-director of the University of Michigan Law School’s Empirical Legal Studies Center.

Prof. Starr observed that

In a recent letter to the United States Sentencing Commission, Attorney General Eric H. Holder Jr. sharply criticized the growing trend of evidence-based sentencing, in which courts use data-driven predictions of defendants’ future crime risk to shape sentences. Mr. Holder is swimming against a powerful current. At least 20 states have implemented this practice, including some that require risk scores to be considered in every sentencing decision. Many more are considering it, as is Congress, in pending sentencing-reform bills.

She adds that

The basic problem is that the risk scores are not based on the defendant’s crime. They are primarily or wholly based on prior characteristics: criminal history (a legitimate criterion), but also factors unrelated to conduct. Specifics vary across states, but common factors include unemployment, marital status, age, education, finances, neighborhood, and family background, including family members’ criminal history.

The use of by evidence-based sentencing may also be unconstitutional because “[t]he Supreme Court has consistently held that otherwise-impermissible discrimination cannot be justified by statistical generalizations about groups, even if those generalizations are on average accurate. People have a right to be treated as individuals, and individuals often do not conform to group averages.”

In her response to criticism from General Holder and Ms. Starr, Ms. Milgram, a former AG appointed by Gov. Jon Corzine (D), defended the Arnold Foundation’s Public Safety Assessment-Court tool.

The PSA-Court provides judges with a data-based risk assessment that they can use to inform their decisions as to whether to detain or release a defendant pretrial. The tool, which does not employ the factors that have recently been critiqued as potentially discriminatory, is helping judges accurately determine which defendants should be detained because of the threat they pose to public safety, and which can be safely released. The PSA-Court is now being used in seven cities and counties across the U.S., as well as throughout the state of Kentucky. Data compiled after the first six months of use in that state show that Kentucky is detaining fewer defendants. And yet even with more people on pretrial release, there has not been a spike in crime. In fact, crime levels in the pretrial period have dropped by nearly 15 percent. And the assessment has proven to be race- and gender-neutral.