Expert Commentary

Choosing not to prosecute low-level crimes may reduce future crime, research finds

Three researchers examined how decisions to prosecute people arrested on suspicion of committing low-level crimes affected future criminal activity in a populous northeastern county. Here's what they found.

(Colin Lloyd / Unsplash)

In most U.S. jurisdictions, an arrest by police does not necessarily lead to criminal charges, especially for low-level offenses. Government prosecutors often have broad discretion over whether and how to charge those arrested, based on evidence law enforcement personnel present them.

New research in the Quarterly Journal of Economics, which analyzes prosecution decisions in one populous northeastern county, finds that adults arrested on suspicion of committing non-violent misdemeanor offenses who are not criminally charged are less likely to face criminal complaints in the future than those who are charged.

The finding can inform journalists and policy makers who want to assess the consequences of recent decisions from district attorneys around the country to reduce or eliminate the prosecution of certain low-level offenses, including in New York County, Los Angeles County, Dallas County and St. Louis.

The January 2023 paper, “Misdemeanor Prosecution,” offers some of the first real-world evidence of what happens to crime incidence when local prosecutors decline to charge individuals suspected of committing low-level offenses, such as trespassing, having small amounts of illegal drugs, or disorderly conduct.

The authors initially focus on the cases of what they term “marginal defendants” in Suffolk County, Massachusetts, which includes Boston, with data on roughly 67,000 prosecutorial decisions from 2004 to 2018. They then examine before-and-after consequences of a 2019 decision from then-Suffolk County District Attorney Rachael Rollins to decline to prosecute most low-level offenses.

Marginal defendants are those whose cases straddle the border of prosecution and non-prosecution. They are individuals arrested for similar, minor offenses — some were prosecuted during the period studied, others were not. Generally, those arrested on suspicion of serious crimes, like murder or arson, are very likely to be prosecuted. For those arrested for low-level misdemeanor offenses, prosecution decisions during the period studied were up to Suffolk County assistant district attorneys, who were randomly routed cases.

Of the cases studied, 1 in 5 were not prosecuted. Of those that were prosecuted, nearly 3 out of 4 ended without criminal convictions.

In Suffolk County and many other jurisdictions, an official charge will show up on a criminal record check, “available to employers under certain conditions upon request, even if the defendant is not convicted on any charges,” write the authors, Rutgers University economist Amanda Agan, Texas A&M University economist Jennifer Doleac and Anna Harvey, a professor of politics at New York University.

California, Kentucky, New Mexico and New York are the only states where formal charges that do not lead to convictions do not appear on typical background checks.

The authors show that in Suffolk County simply arraigning an individual on criminal charges can affect recidivism, which refers to the likelihood someone will encounter the criminal legal system again, such as being arrested on suspicion of committing another crime.

The authors mark an arraignment as the start of a criminal proceeding — the start of prosecution. For an average marginal case not prosecuted, the individual was about half as likely to face a new criminal complaint in subsequent years as someone who was prosecuted.

“Put the other way, being prosecuted increases your probably of recidivating,” Agan says.

Marginal cases in the sample for those without a prior criminal record were 81% less likely to face a new complaint over roughly the next half-decade if their initial case was not prosecuted.

“If you already have one of these charges on your criminal history, getting an additional one may not hurt you quite as much as going from zero charges on your record to one on your record,” Agan says. “That criminal background check — that line on your criminal background check — can make it harder to get employment, harder to find housing. It can have all sorts of collateral consequences that seems to make it so that you’re more likely to end up with criminal justice contact in the future.”

The reductions in recidivism hold for six years and “if anything, impacts appear to grow over time,” write Agan, Doleac and Harvey.

“We were surprised,” Harvey says. “We had a first draft of the paper, and it showed these really large effects. It was surprising, so we took another year of doing everything we could to see if the results would go away, and consulting with all of our colleagues and presenting it in workshops, and nobody could ever find anything wrong.”

The findings are instructive but not necessarily generalizable to other jurisdictions. District attorneys around the U.S. use varying processes for pursuing criminal charges, and there may be demographic, economic and other regional circumstances that also affect recidivism.

Still, one big takeaway is timing can matter. Harvey explains that from the perspective of a prosecutor, the end result is the same whether someone’s case gets dropped before arraignment or the person is brought to court for a first appearance, then their case is dropped shortly afterward. But it is the act of arraignment — of beginning a formal prosecution — that can have lasting effects on crime avoidance, the authors find.

A policy shift in Suffolk County

In March 2019, then-Suffolk County District Attorney Rollins announced her office would no longer criminally prosecute non-violent misdemeanor cases, including those involving shoplifting, minor driving violations, drug possession and trespassing, among others.

Agan, Doleac and Harvey had secured a data-sharing agreement with Rollins in the weeks before the Suffolk County policy was announced.

The policy provided a natural experiment for the researchers to examine real-world outcomes. The rate at which Suffolk County prosecuted non-violent misdemeanors fell sharply after Rollins was inaugurated in January 2019, the researchers find.

As for recidivism, “we find a very similar pattern,” Harvey says. “Cases that are nonviolent misdemeanor cases that are not prosecuted as a consequence of this new policy, those defendants are much less likely to be re-arrested within one year.”

Non-prosecution in Dallas

Most non-prosecution policies are new, enacted just a few years ago. Because researchers need time and data to conduct quantitative studies, there is scant research on the effectiveness of these policies.

This is why the authors of the Quarterly Journal of Economics paper are working with other district attorneys to secure data.

Harvey confirmed the researchers have data sharing agreements with San Joaquin County in California, the Western Judicial Circuit in Georgia, Ramsey County in Minnesota and Kings County in Brooklyn, New York. The researchers are also working on a data sharing agreement with the Manhattan district attorney’s office.

“We encourage other jurisdictions to partner with researchers at their local universities — or with us, for example,” Harvey says. “We are quite vocal in saying this is one study in one city. And that’s why we’re investing a lot of time in trying to get data for other offices and pursuing replications in other areas.”

But there are findings from at least one other analysis: A research partnership between Southern Methodist University and Dallas County is exploring how a 2019 decision from District Attorney John Creuzot to not prosecute most first-time misdemeanor marijuana possession cases has played out in terms of racial equity.

The most recent report from this partnership explains that by “referring arrests and citations for prosecution, police choose which cases enter the criminal legal system. But prosecutors decide which cases (and which defendants) remain in the system.”

The report, which is not peer-reviewed, finds police across Dallas County “made 31% fewer referrals for marijuana possession in 2019 than they had in 2018.”

Yet, even though people from different racial groups use marijuana at similar rates in Texas, the proportion of Black people referred for misdemeanor marijuana possession in Dallas County increased from 54% in 2018 to 56% in 2019. In other words, although overall referrals dropped sharply, the likelihood of a Black person being among those referrals increased.

The director of the Dallas County research project, Southern Methodist University professor of law Pamela Metzger, stresses in the report the ongoing and “urgent need to investigate the relationship between prosecutorial reform and policing practices.”

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