Wilson Center, Berkshire District Attorney's office release unprecedented trove of data on plea agreements
A new report on the factors prosecutors consider in making plea deals establishes baselines to measure progress, enhances transparency with the public and justice actors, and identifies areas of strength and opportunities for improvement in practices.

The Wilson Center for Science and Justice and the office of Berkshire District Attorney Andrea Harrington have completed a year-long study on the anatomy of a plea agreement in criminal courts and are making the rich and unprecedented data available to the public.
The partnership created a process for prosecutors in the Berkshire District Attorney’s Office to document and share a multitude of novel data points for researchers at the Wilson Center. The resulting report establishes baselines to measure progress, enhances transparency with the public and justice actors, and identifies areas of strength and opportunities for improvement in practices.
“The duty of elected prosecutors to protect public safety and ensure fairness are complementary. Data collection is critical to ensuring both because transparency informs criminal justice policy and enhances the public’s trust in the criminal legal system," Harrington said.
"This data demonstrates that Berkshire prosecutors are protecting the public from individuals that pose a risk to the community and seeking therapeutic treatment when appropriate, but also quantifies racial disparities that have long undermined the trust that people of the Commonwealth place in public safety agencies. I hope these findings will support justice actors across the Commonwealth in ending the scourge of systemic racism in our courts."
Harrington said she engaged in the project with the Wilson Center with the intent of identifying areas for improvement, and thanked prosecutors and staff in her office for documenting the plea process in Berkshire courts. Berkshire prosecutors recognized the tremendous discretionary power they wield and how their decisions impact not just individual cases but the entire community, she said.
The research builds on a previous Harvard study commissioned by the late Chief Justice Ralph D. Gants, which documented racial disparities in Massachusetts criminal courts by identifying areas in charging and disposition that drive longer sentences for Black and Brown people. That study noted the need for more research around plea dispositions, which account for approximately 90-95% of all criminal case dispositions.
Massachusetts district attorney offices utilize a two-decades old case management system that is not designed for data collection and analysis, leaving researchers and justice actors little opportunity to analyze practices through aggregated data. Prosecutors have not been required to document aggravating and mitigating factors considered during negotiations.
The Berkshire District Attorney’s Office worked collaboratively with researchers at the Wilson Center to identify the type of data needed for a quality analysis and developed a program to collect it.
“These reports are a first look at the nature of these complex decisions and how different case circumstances influence plea outcomes,” said Duke research fellow Dr. Adele Quigley-McBride. “I am grateful for and deeply admire how the Berkshire prosecutors dedicated their time and energy towards better understanding the plea process.”
In District Court, prosecutors documented detailed decision-making on more than 1,000 cases. The Wilson Center found that the prosecutors heavily weighed available rehabilitative options and frequently noted a lack of available resources, limiting rehabilitative options for some defendants.

Among the factors prosecutors reported were risks to public safety, criminal histories, crime deterrence, the presence of firearms, the risk of recidivism and the nature and circumstances of the offense as top considerations for more punitive offers. Among the collateral consequences prosecutors reported for offering more leniency were the impact of the defendant’s loss of a driver’s license, ability to contribute to society, find employment, return to their life after resolution, accumulating debt, and incurring hardships to the defendant’s family. The Wilson Center also found that District Court prosecutors considered those under the age of 25 stronger candidates for leniency.
The study showed that judges play an active role in reducing sentences, including in the most serious cases by frequently imposing more lenient sentences than prosecutors requested.
The Wilson Center found that Superior Court prosecutors engaged in “charge bargaining” to avoid mandatory minimum sentences in effectuating a plea because mitigating circumstances warranted doing so.
The Wilson Center quantified the expected racial disparities in the plea outcomes for minor offenses in District Court. The study found that a higher proportion of Black defendants pled guilty in District Court than white defendants, who more frequently obtained continuances or other alternative dispositions. The study also noted racial disparities between the type of defense attorneys that individuals retained and demographic disparities in those who are victims in cases.
Prosecutors documented the levels in which victims’ desires and participation in the court process influenced a plea offer. The study found that the Berkshire District Attorney’s Office placed a high priority on the role of victims, especially in the most serious cases, that prosecutors spoke with victims about the cases frequently, and many attended court hearings and/or produced impact statements.
These findings also highlight the impact of the COVID pandemic on plea outcomes. Prosecutors reported that significant delays in some cases were considered in support of more lenient plea recommendations. The court did not hold trials for approximately 18 months, which provided little to no incentive for a defendant to plea and cases weaken over time or victims lose interest.
“We hope that these findings inform future policies and decision-making,” said Brandon Garrett, director of the Wilson Center and the L. Neil Williams, Jr. professor of law at Duke Law School. “We all need to build on this work. No data like this exists elsewhere in Massachusetts. That raises real questions about what disparities or unfairness might remain in the shadows, impossible to detect from the basic outcomes reported in court. We hope that judges, prosecutors, and defense lawyers follow the leadership demonstrated by District Attorney Harrington during this year of impactful work.”
The research is only a start. The Wilson Center is conducting a similar project in Durham, N.C. and is looking to sign an agreement with other types of justice agencies which will allow cross-sector analysis of adversarial desires.
"As a law student, it was an amazing experience to help examine the inner workings of plea bargaining—something I have only learned about in the abstract in my classes," said Duke University researcher Morgan Kelleher said. "The information described in this report is so important for identifying the aspects of the process most in need of improvement and ensuring that our criminal justice system functions equitably for all people.”
The full reports of the study are available here:
https://wcsj.law.duke.edu/wp-content/uploads/2022/12/Berkshire-One-Year-Report-PART-ONE.pdf
https://wcsj.law.duke.edu/wp-content/uploads/2022/12/Berkshire-One-Year-Report-PART-TWO.pdf