Age and Crime

The dramatically higher age-specific offending rates for young people suggest that shifts in the age-composition of the population could produce sizable changes in societal crime rates. The so-called baby-boom generation born between the end of World War II and the early 1960s brought a large, steady increase in the proportion of the population aged twelve to twenty-five—the most crime-prone age group—during the 1960s and 1970s, a period when the nation's crime rate was also increasing steadily. Ferdinand found that about 50 percent of the increase in the index crime rate during the 1960s could be attributed to population shifts such as the baby-boom generation's movement into the crime-prone years. Similarly, Steffensmeier and Harer found that virtually all the reported decreases in the UCR and NCVS Index crime rates during the early 1980s could be attributed to the declining proportion of teenagers in the population—that is, to a "baby-bust" effect.

More recently, Steffensmeier and Harer reported that the large impact of age-composition on crime rates during the 1980s had diminished during the 1990s, and that the broad decline in both the UCR and NCVS crime rates since 1992 (the years of the Clinton presidency) cannot be solely attributed to changes in population age composition. One explanation of the recent downtrend has attributed the decline to dramatic increases in incarceration rates that presumably incapacitate or prevent crimes by locking up high-frequency offenders who commit a disproportionate amount of all crimes. However, the rise in incarceration rates extends backwards to at least the late 1970s, and therefore considerably predates the 1990s drop in crime. Therefore it appears unlikely that higher imprisonment rates explain much, if any, of the recent drop in crime—just as they do not account for the rise in crime in the late 1980s.

Alternative explanations for recent downward trends in crime rates include the strong economy and low unemployment of the 1990s, an abatement of the crack epidemic of the late 1980s, and the wide variety of community-level criminal justice initiatives undertaken in the 1990s, such as Operation Weed and Seed, Pulling America's Communities Together, SafeFutures, and community policing. Also, Steffensmeier and Harer speculate that offenders may be shifting from risky, low-return offenses like burglary (also robbery) to others that are more lucrative (drug dealing) or less risky (fraud).