Berkeley -- Remember those unsettling crime forecasts for the 1990s? Leading policy experts and law enforcement officials cautioned that changing demographics would create a swell in the nation's youth and young adult populations, resulting in a dangerous crime wave of "super-predators."
Not only didn't that crime wave occur, the opposite happened: According to new research by a University of California, Berkeley, law professor, the crime rate dropped dramatically during the 1990s, falling 40 percent in cities and states across the country and in all major crime categories from homicides to auto thefts, producing the longest and deepest crime decline in the United States since World War II.
In his new book, "The Great American Crime Decline," (Oxford University Press, 2007) Franklin Zimring of the UC Berkeley School of Law (Boalt Hall) points out that while there are no easy, clear explanations for this unexpected drop, the size of the decline provides important, instructive lessons for policy makers and law enforcement officials grappling with today's toughest violent crime problems.
The research also provides fertile ground for additional study into the causes of the 1990s crime decline and American crime trends in general. Zimring will discuss this research Friday, Feb. 16, during a symposium in San Francisco at the annual meeting of the American Association for the Advancement of Science (AAAS). The AAAS is the world's largest general federation of scientists and the publisher of the journal Science.
In connection with the conference, Zimring also will appear on National Public Radio's "Science Friday" show this morning along with other researchers from the conference.
Zimring's research suggests that the nation's crime rate - which has leveled off and remained flat since the year 2000 - could drop further and that major crime declines can happen without big changes in population and without substantial improvements to the nation's urban environment.
The case in point is New York City. During the 1980s, and as that city hit its violence peak in 1990, New York City seemed locked in a violent crime epidemic. However, from 1991 through 2004, the city's crime rate for serious offenses dropped about 75 percent - almost twice the national average.
"The most remarkable part of this story," Zimring writes in his book, "is not what changed in New York City over the 1990s, but what did not change, which was most of the city of New York. There were clever programs to stop fare avoidance in the subway system, but the subways didn't change, nor did the schools, the streets and surface transportation systems, the population, or the economy."
Part of the drop came from relatively modest improvements in policing, said Zimring. The New York City police department made three important changes that collectively were significant. It increased its work force by 35 percent, or 13,000 people - roughly the size of many of the nation's biggest city police departments in 1990. It also engaged in more aggressive policing, such as making stops that were independent of arrests and establishing a misdemeanor arrest program for drug offenses as well as other public-order offenses. And it changed its management style, objectives and techniques, including placing more officers out on patrol.
"Even if only 25 to 50 percent of the total New York (City) drop was police-related, the big news from New York (City) is we don't have to change the fundamental condition of modern urban life or the population," said Zimring. "We just have to find the right combination of ingredients in urban design, prevention and policing, and that may be different for different cities. You just have to tinker at the edges, and you can get amazing results."
Finding that right mix of ingredients could prove to be the hard part, he said, since cities and counties vary in geography, population, hand-gun ownership, even local crime conditions. Further, Zimring's research indicates that isolating a single factor as the cause for a decline in crime can be elusive.
In his study of the 1990s crime decline, the professor found multiple possible contributors to the decline - including unprecedented economic gains, favorable demographics in terms of a drop in the high-risk population of teens to 29-year-olds, and an increase in incarceration -- with no single factor playing a dominant role.
Zimring also notes that while the United States did experience a drop in its high-risk population during the 1990s and an increase in individuals jailed and imprisoned during the 1990s, such trends occurred in the late 1980s as well, a time when serious crimes in the United States increased.
Further complicating matters was Canada. Zimring found that during the 1990s, Canada experienced a crime decline that mirrored the one in the United States. Canada's crime rate dropped about 30 percent in most categories for eight years after 1991, a near-perfect match with the U.S. pattern, and happened during a period in which Canada's prison population declined, there were fewer police officers on the streets, and there were moderate, not booming, economic gains.
Canada, however, like the United States, did experience a drop in the relative size of its youth population during the 1990s.
Even with so much good news on law enforcement and the economy, Zimring said, much of the great American crime decline could be a cyclical phenomena, unrelated to public policy changes or new approaches to police work.
The statistical data and analytical methods currently available to isolate the impact on crime trends of police work, incarceration rates, the economy and other such factors are not strong. It is this lack of strong, reliable, analytical tools that Zimring believes caused experts to err in their predictions and dire warnings of a 1990s crime wave.
Still, Zimring contends that while 40 percent of New York City's 75 percent drop in crime reflects the same mix of factors that drove the national crime rate down 40 percent, much of the remaining 35 percent drop is almost certainly due to the three major changes in New York City policing: more police, better management and more aggressive policing.
The law professor contends that law enforcement agencies would do well to try a number of targeted policing approaches and tailor them to their jurisdictions.
In New York City, the total drop has led to 1,600 fewer homicides per year. Even if police changes prevented only 25 percent of the total decline, Zimring pointed out,that would be more than one life saved every day.
"Whatever else is known about crime in America," Zimring writes in his book, "the most important lesson of the 1990s was that major changes in rates of crime can happen without major changes in the social fabric."