Philadelphia has way more fatal shootings than expected for a significant city — and NYC is far safer, a brand new study says

The recent high-profile mass shootings at SEPTA bus stations are over Philadelphia commuters on high alert. Two gunmen opened fire at a bus stop within the Ogontz district on March 4, 2024, striking and killing five people 17-year-old Dayemen Taylor. Two days later a bunch of teenagers shot eight other teenagers waiting at a bus stop near Northeast High School after school.

So far in 2024, 86 people were killed in Philadelphia – the overwhelming majority of them after being shot. Yet town continues to be heading in the right direction to record its lowest variety of murders since 2016, an indication of how violent it has been in recent times.

A latest study by urban researchers at New York University Ryan Succar And Maurizio Porfiri uses a technique often called urban scaling to know how violence in Philadelphia and other cities compares to what could be expected in cities given their size. They answered the next questions for The Conversation.

What is urban scaling?

Large cities – filled with thousands and thousands of individuals interacting with one another – are complex systems.

Urban scaling laws are used to clarify how certain characteristics of cities—from average salaries to street space to COVID infection rates—increase or decrease as populations increase. These changes are circuitously related to population increases and reduces. In other words, the connection is just not linear.

As surprising as it could sound, some variables – murder rates, for instance – are inclined to increase even faster than population growth. Mathematicians call this superlinear growth. A bigger population subsequently results in a statistical increase not only within the variety of homicides, but in addition in the speed of homicides relative to the population.

Other measures reminiscent of gun ownership and gun access may grow more slowly as urban populations increase. This is known as sublinear growth. Our study shows that the share of gun owners and accessibility, as measured by the variety of licensed gun sellers in a given metropolitan area, generally decreases because the population increases.

To get a more nuanced view, urban scientists like us use a measure called Scale-adjusted metropolitan indicator. This indicator was originally proposed by Luis Bettencourt, an urban scholar on the University of Chicago and the Santa Fe Institute. It takes under consideration non-linear scaling patterns observed in cities, allowing for a more accurate comparison of various urban areas.

For our study, we used SAMI to rank 833 U.S. metropolitan areas when it comes to murder rates. We collected data from the Centers for Disease Control and Prevention and the Bureau of Alcohol, Tobacco, Firearms and Explosives on local rates of gun ownership, accessibility, and homicide prevalence. The data takes under consideration all weapons owned – no matter whether or not they were acquired legally or illegally.

How does Philly compare to other major cities?

In Philadelphia, there are far fewer homes with firearms and fewer gun dealers than people would imagine. And yet Philadelphia continues to be seeing higher-than-expected levels of violence.

Among the nine cities with greater than 5 million residents, the Philadelphia metropolitan area – which incorporates Camden, New Jersey and Wilmington, Delaware – had the second largest deviation from expectations when it comes to size. Chicago had the most important deviation, meaning it was more violent by the most important amount than its size would suggest.

Compared to other cities of various sizes, Detroit also has more violence than expected for its population, while Miami is average and Boulder is far safer than expected.

While often perceived as unsafe, New York City is definitely significantly safer than one would expect given its population. In fact, with greater than 5 million residents, it is taken into account the least violent city.

The positive leads to New York suggest that violence reduction efforts there have been successful, while efforts in Philadelphia will not be working as well.