In recent years, the major barometers for crime have fallen significantly. Crime is a slippery thing to measure, but both government crime indices and victimization reports indicate that violent and property crimes have declined steadily since their peak in 1980. Few dare to call it a trend, however. The decline is fairly slight compared to the long climb in crime rates since 1960.
What does it mean? A group of the nation's top criminologists gathered at the University of California at Los Angeles last week to figure out if crime really is going down, why that may be, and why many Americans perceive crime as increasing.
The easiest explanation for the crime-rate decline lies in arithmetic -- adding up the number of teen-agers in the United States. The peak age for committing robberies, for example, is about age 17. The nation's peak year for robbery arrests, 1980, was also the nation's peak year for the number of 17 year-olds. Robbery arrests among 23-year-olds are only half of the level for those age 17. Violent crimes in general follow this same pattern.
Alfred Blumstein has done the arithmetic. The director of the Urban Systems Institute School of Urban and Public Affairs at Carnegie Mellon University notes that not only were there more 17-year-olds to commit crimes in 1980, but a larger share of them did so than have the 17-year-olds of other years.
The reasons for this may lie with the pressures and perils of having a larger group of teen-agers, with fewer adults, than other generations.
For whatever reasons, Dr. Blumstein figures that the age-group factor accounts for about 10 to 20 percent of the changes in the crime rate. So by this indicator, the next rise in crime should come in the middle of the next decade. What accounts for the remaining 80 to 90 percent of the crime drop is tough to figure, the experts say.
What bothers Rutgers University Prof. Freda Adler is the notion that crime is destined to ride the waves of demographics. ``I don't think we have an inevitable criminality, even though we have a risk-prone group.''
In a United Nations project, Dr. Adler studied 10 countries ranging from rich to poor, from all political persuasions, with low crime rates. What they all shared, she says, were ``very, very strong informal social controls.''
These controls ranged from religion in some Moslem countries to the powerful sense of shame in Japanese culture to Switzerland's strong citizen participation in the justice system.
The lack of these informal social controls, Adler suggests, is part of the crime problem in the US.
It may also explain why many Americans feel public order has broken down to the point that crime has become society's worst problem.
``Visible signs of incivility and decay [such as rowdy kids on a street corner or broken windows] are at least as important in people's perception as actually becoming victims of crime,'' says James Q. Wilson, visiting professor at University of California at Los Angeles.
So Dr. Wilson recommends cleaning graffiti from subway cars, fixing broken windows as soon as they are broken, and using police foot patrols to create an atmosphere in which people feel safer and more in control of their environment -- even though this may not improve the crime rate at all.
The public perception of crime is also determined largely by the rare, often unusual, cases that make news. Issues like the death penalty or the insanity defense are involved in an almost negligible portion of the nation's case load, but they pack symbolic power for public opinion.
``The public does't believe crime is down,'' says Barry Krisberg, president of the National Council on Crime and Delinquency. ``People really believe that police and the courts can't protect them.'' Why? Publicity and detailed reports on victims' rights ``may have scared . . . the public,'' he says.