he arranged for me to spend a day with a colleague of his, Claire White. The two of them have been running a multimillion-dollar “hot spot” research project in Baltimore since 2012—studying 450 street segments all over the city. “It’s becoming well established that crime is highly concentrated,” White explained. “[Weisburd] has shown us that across numerous cities with different types of data. The big question is why? What is it about these places that have such a high concentration of crime?”
White and Weisburd hired forty student interviewers. They send them out every day to document the condition of those 450 segments, gathering as much information as they can on their residents. “We ask about what we call collective efficacy, willingness to intervene,” White said. “If there’s kids climbing on a parked car, how willing are your neighbors to say something? If the local fire station was going to be shut down, how willing are your neighbors to do something about it? Kind of this willingness to be involved as well as trusting. Do you trust your neighbors? Do you share the same values as your neighbors?…We have questions about the police: Do you think the police treat you fairly? Do you think the officers treat people with respect?”
For comparison purposes, some of those street segments are “cold” spots, defined as blocks with fewer than four police calls a year. A hot spot is anything with more than eighteen police calls a year. Keep in mind that Baltimore is an eighteenth-century city—the blocks are really short. So that’s a minimum of eighteen police calls along a street segment that you could walk in less than a minute. White said that some of the streets in the study had over six hundred calls for service in one year. That’s what Weisburd means by the Law of Crime Concentration. Most streets have none. A small number of streets are home to virtually all the crime in the area.
White and I began our tour in West Baltimore, not far from the city’s downtown.
“It’s notorious for being one of the pretty high crime areas. It’s where Freddie Gray was arrested and where the riots took place,” she said, referring to the 2015 case of a young African American who died in police custody, under suspicious circumstances, leading to angry protests. “If you’ve seen The Wire, they always talk about West Baltimore.” The area was typical of an older northeastern city: narrow streets, red-brick townhouses. Some blocks had been gentrified, others not. “There’s definitely many areas where you’ll be walking and you feel you’re in a nice neighborhood, right? You feel comfortable,” White said, as she drove through the heart of the neighborhood. “Then you turn the corner and you’re in a street that’s all boarded up. It’s a ghost town. You wonder if anyone even lives on the street.”
She took me to the first of the street segments being studied and parked there. She wanted me to guess whether it was a hot spot or a cold spot. On the corner was an exquisite nineteenth-century church, and behind it a small park. The block had elegant European proportions. The sun was shining. I said I thought it must be a cold spot. She shook her head. “This is a violent street.”
She drove on.
Sometimes a street’s identity was obvious: a bedraggled block with a bar at one end and Slick Rick’s Bail Bonds at the other was exactly as it looked—a double hot spot, bad for both crime and drugs. “There’s ones where it’s very clear, right?” White asked me. “You get out of the car and the people on the street start shouting out their codes for a police officer coming.” She started laughing. “I love going out with the field researchers when they’re like, ‘That’s the code for us being on the street.’” Once, in broad daylight, White’s field workers found themselves in the middle of a gun battle; there was little ambiguity about that segment.
But some bedraggled streets were perfectly fine. Once, in the midst of a particularly dismal stretch, we came across a little oasis: two consecutive street segments of manicured lawns and freshly painted houses. One large abandoned building had a sign posted in its window, a reference to John 14: 2, 3: “In my father’s house there are many rooms.” Was a glimpse of irony evidence of function or dysfunction?
I asked White to explain what tipped a street segment one way or the other. Sometimes she could. Usually she