The United States has the largest incarcerated population in the world, and Black Americans are overrepresented in its ranks. We tend to think of the problem largely in terms of overcrowded state and federal prisons, but there’s another force driving mass incarceration: local jails.

Jail populations grew dramatically over the last few decades, with annual admissions almost doubling from 1983 to 2013 according to the Vera Institute of Justice, and most of the people sitting in local jails have not been convicted of a crime. The majority of those in jail are awaiting trial, many because they can’t afford bail; others may be there because they have been convicted and given short-term sentences.

In 2015, the MacArthur Foundation launched the Safety and Justice Challenge, an initiative aimed at reducing local jail populations across the country. Back then, much of the conversation around mass incarceration involved prisons and the need for sentencing reforms, particularly around low-level drug offenses and mandatory minimums. Under the guidance of Laurie Garduque, the director of the MacArthur Foundation’s criminal justice program, the Safety and Justice Challenge set out to better understand what experts sometimes call “incarceration’s front door,” and to partner with local jurisdictions looking to reduce their jail populations.

I spoke with Garduque about the scope of local jail incarceration, what changed during the pandemic, and what the data says about the effects of pretrial release. Our interview has been edited for length and clarity.

What role do local jails play in mass incarceration?

There are 700,000 people in jail on any given day, and there are 1.2 million people in prison. What is overlooked is the number of people who are admitted to jail annually, which is roughly around 10 million jail admissions. Another important distinction between the jail population and the prison population is that, of the people who are held in jail, about two-thirds of them are being held pretrial. That means they haven’t been convicted of a crime and they’re innocent unless they’re proven to be guilty.

Roughly 75 percent of those individuals are there for what we would consider less-serious nonviolent offenses. Then you start to look at the racial and ethnic disparities, and that’s also quite alarming — people of color are overrepresented in the jail population three to four times what they are in the population.

One of the main rationales for locking people up pretrial is this idea that having someone charged with a crime released is a risk to public safety. What does the data say about that?

Many of the people who are detained do not pose a risk to public safety, and there are ways to determine that in the decision-making process. We know from the Safety and Justice Challenge data and other data that people who are deemed low-risk who are not booked into the jail are not later arrested for more serious offenses.

There are some folks who say you can’t identify the people who are at greater risk for not showing up for their court date, who will remain on the street and commit serious offenses — there’s data that counters that. There are a variety of best practices about enabling people to stay in the community while they are awaiting trial and ensuring that they won’t commit a new offense or they won’t pose a risk to public safety. There is better data that folks can use to make those determinations.

What are some of the other reasons people who haven’t been convicted get stuck in jail?

There are what we call “legal financial obligations.” Money bail is a legal financial obligation, but there are also people who are arrested because of failure to meet legal financial obligations — anything like child support or parking tickets or other fines and fees that the court might administer. Unless they can come up with the money to pay for these, then they stay locked up.

There are individuals who remain locked up because they don’t have anywhere to go after they’ve been released from jail. There’s a reluctance on the part of courts to simply allow them to go back out into the community if they don’t have a residence or stable place to be released on their own recognizance.

Individuals can also be detained because they have developmental disabilities or behavioral health issues or mental health disorders — they’re considered at risk for being on the street, or they could be considered a risk to themselves. Many jurisdictions also lack adequate pretrial supervision, which is a way to connect with folks in the community for support to make sure they will show up for their court date.

Do we have a sense of what the average length of stay looks like for someone who is in pretrial detention?

The average length of stay in the decade before Covid was between 21 and 26 days, and that has increased with Covid. Many jails have changed their admission practices because of Covid to keep the numbers down, but the length of stay increased. It’s alarming how long some people remain in jail awaiting trial, even with speedy trial provisions and what we consider national standards for how long trials take.

Why has the amount of time in pretrial detention gone up since Covid?

Arrests and bookings into jail declined, and a lot of the people who were in and out in 72 hours because they committed low-level offenses were simply not even being booked into jail. While the jail population has dropped, the racial and ethnic disparities have gone up.

The people who were arrested are those who were charged with more serious offenses, and they’re either deemed as being at risk for failing to appear for their court date or posing a risk to public safety, in which case they are being detained without the option for bail. Because courts were not in many cases fully operating or not having jury trials, the people are just languishing in jail. This was a problem pre-Covid, and Covid has just exacerbated it.

What are the challenges that you’ve seen when it comes to getting more jurisdictions to adopt measures that would reduce local jail populations?

Some of it is about not knowing what these alternatives are, or knowing what the best practices are, or knowing what the research says. Some of it is about challenging the status quo and the culture of a particular city or county. Some of it is just that it’s often difficult to have the different system stakeholders agree. You see that playing out in several jurisdictions right now where the mayors are undermining prosecutors, or there’s a debate between the police chief and the state’s attorney about what best practices are.

We have a very punitive system to start with. In part, that’s because we think that punishment is a deterrent. Yet we know that it isn’t. What we’re trying to do is give people better information, give them the support, create incentives for them to be more collaborative, to engage the community, to think upstream from the criminal justice system to what alternatives are in holding people accountable that won’t compromise their future life chances.

The surge in homicides has made people wary of many of those changes. But it’s clear in our data that those changes that kept people out of jail did not drive the surge in homicides because it’s not the case that the people who were kept out of jail are later being arrested for violent crimes. What we’ve learned is we can in fact drive incarceration rates down and that the Safety and Justice Challenge sites have done so at a greater rate than what is evident nationally and without compromising public safety.

The increase in violent crime has happened only with respect to homicides, in some cases aggravated assault, but overall violent crime still continues to decline. While I don’t raise these issues to minimize the tragic loss of life and the concerns that we have about violence, to attribute it to bail reform or progressive prosecutors is just misleading. It’s not a valid argument to make if you look at the data.

What are some of those alternatives to jail?

You can issue a summons for them to show up for a later court date. If people have mental health or substance abuse issues, you can take them to a crisis triage center so they become stable and can return to the community or are linked to appropriate services. Once you’ve been charged, you could have an attorney show up at first appearance and make a case that the person doesn’t need to be detained because they don’t pose a risk to themselves or others with respect to safety.

You can put in automated court reminder systems. Some of our jurisdictions have social workers in their public defenders offices so folks are tracked and reminded to show up for their court date. There can be automatic reconsideration of money bail if someone is detained and they can’t make bail. It’s somewhat controversial, but some jurisdictions use risk assessment tools to determine under what conditions someone can remain in the community or be released on their own recognizance.

There are lots of other steps that can be taken, but you have to have the community and stakeholders agree that these are solutions to problems you’re trying to solve, and it’s going to be different in every community. What works in Philadelphia won’t necessarily be what works in Chicago, Toledo, or Tucson.