Crime in New York City

I had lunch with a friend yesterday and I promised him that I’d dig up the violent crime figures for New York City. Here they are:

This chart alone should provide you with pretty good clues to the answers to these questions:

1. Did David Dinkins have a pretty good record on crime?
2. Was Rudy Giuliani’s adoption of broken windows policing responsible for NYC’s crime decline in the 90s?
3. Did Mike Bloomberg’s stop-and-frisk policing reduce crime in the 2000s?
4. Did Bill de Blasio preside over an upsurge in crime in the aughts?

Here are the answers:

1. Yes: violent crime declined 20 percent on his watch. But nobody knew it at the time because no figures later than 1991 were available during the 1993 mayoral race.
2. No. Nothing special happened to the crime rate when Giuliani took over. Violent crime was already declining strongly when he became mayor and continued declining after he left. There’s no reason to think that Giuliani had any special impact.
3. No. Violent crime declined only modestly during his three terms in office.
4. No. Stop-and-frisk ended and nothing happened. Violent crime stayed low.

Conversely, the lead-crime hypothesis predicts very precisely that violent crime should peak right around 1991 and then decline through 2010 as more and more birth cohorts are raised in a lead-free environment.¹ By 2010 an entire generation has reached its most crime-prone years after being raised in a lead-free environment and there are few improvements to be expected going forward. And that’s exactly what happened.

¹Mostly lead free, anyway.