After a bloody Father’s Day weekend that included 19 shootings, 28 victims, and five dead, many in Philadelphia are calling for answers. Between 2015 and 2018, homicides increased by 25 percent. If killings continue at their current rate, the city will experience another increase in homicides in 2019.

Thomas Abt, a research fellow at the Harvard Kennedy School of Government, argues that dramatically reducing a city’s homicide rate over the span of just a few years is possible. That is the core message of his forthcoming book, Bleeding Out: The Devastating Consequences of Urban Violence — and a Bold New Plan for Peace in the Streets.

Abt told The Inquirer about what his findings could mean for Philadelphia.

What do you mean when you say urban violence?

By urban violence I mean the violence at the intersection of youth violence, gang violence, gun violence, and street violence. It’s the type of violence that claims the most lives in terms of homicides in the United States, but in my view, it doesn’t really get the attention it deserves.

In your book, you call urban violence “sticky.”

Yes, because shootings and killings cluster around a surprisingly small group of people, places, and behaviors. Violence doesn’t concentrate among entire classes of people, like young men of color — it concentrates among a few violent individuals who are often connected to each other via informal social networks. It also doesn’t cluster in whole neighborhoods — it clusters in micro locations that are often known as “hot spots.” Even in the most allegedly dangerous neighborhoods, most people are not dangerous.

What do most people get wrong about urban violence?

Most people talk about urban violence as a function of some other broader phenomenon. Progressives talk about it as a function of poverty and inequality. Conservatives talk about it as a matter of family or community values. Basically, everybody wants to talk about the root causes, not the proximate causes. What they don’t realize is that if you focus on the violence itself, you can have significant success at reducing urban violence in the short run while working on the broader issues over the long run.

You say that cities can have significant success. What is the secret?

All the most rigorous science points to this: To reduce violence, focus on the damn violence. Don’t work around it. Don’t make it about anything else. Identify the people, places, and behaviors that are driving the vast majority of violence and then address them directly, using a combination of strategies that are focused, balanced, and fair.

What does “focused, balanced, and fair” look like?

Here’s an example: In Oakland they have managed to cut homicides by half using something known as Ceasefire, or the Group Violence Reduction Strategy. The strategy involves creating a partnership between police, community members, and service providers that directly engages with the most violent individuals and groups in a city, offering them a choice along with a very simple message: “We are here to help you, but if you continue to shoot, we are here to stop you.” Then they follow up on those promises. If people are willing to put the guns down, there is an intensive effort to help those people — to get them the treatment and support that they need. But if they continue to persist with violence, there is an effort to hold them accountable and make sure they don’t hurt anyone else in the community.

You reviewed about 1,400 studies for your book. From that evidence, what kind of reductions in homicides can we expect and when?

It’s reasonable to expect that if you take two or three of the most successful approaches out there, implement and coordinate them well, and focus only on the highest-risk people and places, you will see about a 10 percent annual reduction in homicides citywide. That might sound modest, and it is, but if you do that for eight years straight it amounts to a 50 percent reduction. That’s true even assuming that there will be no reduction in the first year because it takes time to put these programs on the ground. If we did this nationwide, in the nation’s 40 most violent cities, I estimate that within a decade we could have a homicide rate that is about the same as Canada’s.

In January, Philadelphia revealed the Roadmap to Safer Communities, a five-year plan to address violence. Following your calculations, and leaving year one constant, would it be fair for us to critique the program if by the end of 2020 we see no reduction?

I reviewed Philadelphia’s plan program. It has a lot of good things, but no plan is perfect. If the plan is not performing, I wouldn’t just throw it away, I would improve it. If a city puts the time in to make a serious plan and then it doesn’t meet expectations, I would recommend revising the plan, not abandoning it completely.

To get the results you describe, you explain that a city should invest about $30,000 per homicide per year in addition to what it’s already spending. In Philadelphia, that would amount to about $46 million more over five years. Does that figure refer to investment in the general well-being of the city, like behavioral health, or something more specific?

Those figures refer to something much more specific. They refer to a small set of strategies focused exclusively on a few hundred of the highest-risk people, in a few dozen hot spots, and on preventing some very specific behaviors like illegal gun-carrying and group conflicts. Because it’s so targeted to the people and places that matter most for preventing violence, you can have real results with a pretty modest investment.

Philadelphia can’t impose gun-control measures. How big of a barrier to reducing urban violence is that?

Limiting legal access to guns is very important in terms of limiting urban violence over the long run, meaning 10 or 20 years out. That said, it’s not likely to have much impact over urban gun violence in the short run. It’s important to remember that urban gun violence — unlike domestic violence, many of the mass shootings we see, and suicides — is usually perpetrated with guns that are already illegal based on the laws we have today. So while we should pursue reasonable restrictions on guns, we don’t have to wait for those measures — we can do something about urban violence today.

Abt’s book, Bleeding Out: The Devastating Consequences of Urban Violence — and a Bold New Plan for Peace in the Streets, is on sale on June 25 at your local bookseller.