Law enforcementThe reasons for NYC’s dramatic crime decline

New York City saw more than 80 percent drop in crime from 1990 to 2009. What are the causes of this dramatic decline? Berkeley Law professor and renowned criminologist, Franklin Zimring, says that “most of the prevailing assumptions that have long driven U.S. crime and drug policy appear to be untrue.”

In his new book, The City That Became Safe, Zimring conducts an investigation of this remarkable phenomenon. His findings — that police strategy played a key role in crime reduction, and that crime plummeted even as prison populations decreased — upset decades of conventional wisdom.

America’s 40 percent drop in crime from 1991 to 2000 remains largely an unsolved mystery, while New York City’s drop — twice as long and twice as large — is the greatest U.S. crime decline on record. A university of California-Berkeley release reports that according to Zimring, a revamped tactical approach by New York police paid giant dividends.

“The NYPD targeted hotspots where crime was most prevalent and persistent, and made a concerted effort to shut down public drug markets,” he said. “Both strategies were extremely effective. The department also increased its manpower and allowed officers to be more aggressive.”

Zimring’s research presents a powerful argument that the factors driving crime are more situational and contingent than previously thought. Criminologists had long assumed that if police camped out in a high-crime area, criminals would simply take their activities elsewhere.

“But it turns out that’s not the case,” Zimring said. “One less robbery on 125th Street doesn’t mean one more robbery on 140th Street; it just means one less robbery in New York that year.”

Oakland Mayor Jean Quan recently unveiled a plan to restore safety to what she says are 100 of the city’s most violent blocks. Zimring believes, however, that a 100-block strategy is too vast for Oakland’s short-staffed and under-funded police department. He also says Quan’s plan fails to identify what services police will de-emphasize in order to focus more heavily on the targeted blocks.

Traditional theorists say that cities can not reduce crime without winning the war on drugs. Zimring’s book shows otherwise, describing how New York’s targeted harm-reduction strategies drastically decreased drug-related violence — even as illegal drug use remained high.

“New York’s drug overdose death rate is down 15 to 20 percent, but drug killings are down 90 percent,” Zimring said. “When you see that, you realize drug violence and illegal drug use may be two different problems.”

The book also debunks the popular theory that imprisoning criminals is essential to lowering crime. While the U.S. incarceration rate increased 65 percent from 1990 to 2009, New York’s dropped 28 percent.

“It shows that you don’t need a mega-imprisonment policy to achieve a substantial reduction in crime,” Zimring said. “What happened in New York also indicates that, contrary to what many had believed, epidemic levels of violent crime aren’t hard-wired into the populations or cultures of urban America.”