Juvenile Crime, Juvenile Justice (2001) / Chapter Skim
Currently Skimming:
Appendix B: The Indeterminancy of Forecasts of Crime Rates and Juvenile Offenses
Appendix B: The Indeterminancy of Forecasts of Crime Rates and Juvenile Offenses
Pages 319-348
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 319... ...
These usually have taken the form of efforts to explain past variations or to project future levels of crime by applying techniques of demographic and statistical analysis. These techniques typically consist of: the application of demographic age standardization methods to combine relatively accurate estimates of the age structure of the American population with age-specific arrest rates for various types of crimes and categories of the population to calculate expected numbers of criminal offenses or crime rates or · the construction of an explanatory time-series regression or structural equation models to explain or predict variations in crime rates over time.
|
From page 320... ...
Yet most projections of criminal and juvenile offending rates and numbers of offenses disregard the uncertainty associated with such projections. To emphasize the significance of the uncertainty of projections of criminal and juvenile offenses, a second objective of the paper is to describe some exercises in the construction of plausible national projections of expected numbers of male juvenile homicide offenders as well as upper and lower bounds for the expected numbers for each year from 1998 to 2007.
|
From page 321... ...
cited the contribution that the post-World War II baby boom generation was making to the crime wave in the 1960s.2 They argued that, during the early 1960s, individuals born in the early years of the baby boom hit peak criminal offending ages, i.e., their late teens and early 20s. Using techniques of demographic age standardization, Sagi and Wellford demonstrated that the population increase in these young ages between 1958 (the low point of national crime rates in the late 1950s)
|
From page 322... ...
, respectively. Even though the increase in offending rates during the 1960s was not as large as the official crime rates would lead one to believe, the disconcerting news was that the rate of violent crimes rose more than that of property crimes among youth during this period.
|
From page 323... ...
They showed that the age composition accounted for approximately 30 to 70 percent of declines in property and robbery crime rates, since the baby boomers had aged past the property crime prone ages of adolescence and the early twenties. Violent crimes had not enjoyed such a large decline as the baby boomers had not quite reached the ages where the violent criminal offending tends to drop that is, the late 20s and early 30s.
|
From page 324... ...
Fox constructed structural equation models that estimated not only the impact that race and age composition had on crime trends, but also that of socioeconomic characteristics of the population as well as police activities and expenditures. Based on his study, Fox concluded (1978:51~: "The crime rate forecasts reveal a general reduction in upward trend during the 1980s and a trend increase during the l990s.
|
From page 325... ...
. In their time-series regression analysis, they included the percentage of the population ages 15 to 29 as the age composition control in the homicide model and the percentage ages 15 to 24 in the motor vehicle theft model.
|
From page 326... ...
They concluded from their analyses that the age structure-crime relationship, at least as evident in the homicide and motor vehicle theft rates series up to the mid-1980s, appeared to be symmetric. Cohen and Land (1987)
|
From page 327... ...
population age composition into the 21st century, Cohen and Land cautiously forecasted generally declining homicide and vehicle theft rates for the post-1985 period into the mid-199Os to be followed by increases into the next decade. Noting that increases already had occurred in the homicide and motor vehicle theft rates for 1985 and 1986 after they concluded their analysis of crime trends in the 1946-1984 period, Cohen and Land (1987)
|
From page 328... ...
Wilson (1995) also warned that rising violent crime trends would only worsen as the echo boomers aged into their crime-prone years a phenomenon that would begin during the first two decades of the 21st century.5 Census Bureau population projections supported this contention (U.S.
|
From page 329... ...
To be sure, the demographic force of increasing numbers of echo boomer adolescents and teenagers up to about the year 2010 is inexorable. Assuming further that age-specific delinquent and crime rates, especially violent crime rates, remain constant at the high levels experienced in the 1985-1993 period, it would appear inevitable that juvenile crimes would increase substantially, especially in the years 1996-2005.
|
From page 330... ...
recently reviewed the effects of age composition and other forces on crime rates. They noted the following plausible explanatory factors: · reductions in drug use and stabilization of drug markets; · tougher laws and enforcement that have deterred and incapacitated offenders; · changes in crime opportunities e.g., due to shifts in the population age structure towards more elderly, who rarely are exposed or have their property exposed to crime risk, improvements in domestic and commercial security, and changes from cash to credit card and electronic transactions; .
|
From page 331... ...
This yielded projections of violent crimes that rise very slowly to the year 2010, rising about 5 percent from 1996 levels; see Figure B-3, which reproduces Figure 14 from Steffensmeier and Harer (1999~. They similarly projected values for property crime rates that rise even more slowly, to about 4 percent from 1996 levels to the year 2010.
|
From page 332... ...
When, however, there are significant turning points or points at which agespecific rates of offending rise or fall significantly, then crime forecasts based on the assumption of fixed age-specific offending rates may be substantially off the mark. This occurred during the 1985-1993 period when age-specific offending rates for teenagers and young adults, due to what Cohen and Land (1987)
|
From page 333... ...
As noted, however, the rising trend in the teenage homicide offending rate of 1985-1993 did not persist. The downturn in the teenage homicide rate in 1994 continued through 1995 and 1996.
|
From page 334... ...
presented a revised forecast of teenage homicide offenders, which is reproduced in Figure B-5. This revised forecast of the numbers of teen perpetrators of homicide assumes constant levels of age/race/sexspecific offending rates at the 1994-1996 average.
|
From page 335... ...
, and even those of Fox (1997) , which did not anticipate the continued downturn of juvenile violent offending rates in the mid-199Os.
|
From page 336... ...
stochastic forecasts, and (3) the combination of statistical approaches with expert judgment.9 The variants approach is the conventional method applied by demographers to produce high, medium, and low projections of expected population size (usually by age, sex, and race)
|
From page 337... ...
In this way, scenarios are like simulations: they show the effects of changing a policy or the working out of societal conditions or trends.l° The high and low projection series also can be viewed as forming projection cones (since they typically expand in width with successive years into the future from the base or jump-off year of the projection series) , within which it is considered highly likely that the actual historically observed population numbers of future years will lie.ll A methodological problem in the use of scenarios is that choices of certain values for some assumptions can imply unreasonable values for others, and the approach can give probabilistically inconsistent indications of uncertainty (Lee, 1999~.
|
From page 338... ...
2Only the results of our projection exercises for annual numbers of teenage homicide offenders are reported here. However, we also have produced high and low projection series of numbers of offenders for the years 1998 to 2007 for the following crimes and population-age groups: white male homicide offenders (ages 18-24, 25-59)
|
From page 339... ...
But, for consistency with high and low projection series, we generated for other crime categories, we used Fox's data series only back to 1980. We also used the update for 1997 of teenage homicide offending rates provided by the Federal Bureau of Investigation at the Internet address: http: / /www.fbi.gov/ucr/prelim98.pdf.
|
From page 340... ...
With respect to plausible upper bounds for the homicide offending rates, we conjectured that if teenage homicide offending rates were to reach 125 percent of the highest rates observed during the 1980-1997 period, the public outcry would be so strong that all sorts of societal homeostatic mechanisms from even more active policing to more active involvement of school, religious, community, and civic organizations in juvenile crime prevention programs would come into play to stabilize the rates and pressure them down again. And yet the possibility of a new wave of teenage homicide offending associated with the coming of age of the echo boomers like that of the 1985-1993 period should not entirely be ruled out of a projection cone designed to contain with a high probability the possible range of future teen homicide offending.
|
From page 341... ...
:, ... J ; ; _ — 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 Year FIGURE B-7 White male homicide offenders, ages 14-17: Observed series 1980 to 1997 with projected upper and lower bounds to 2007.
|
From page 342... ...
This is consistent with our decision to allow the projected lower and upper bounds of homicide offending rates for these two populations to reach the respective limits in five years. Second, at the same time, on the basis of the preliminary evidence regarding homicide trends from 1997 to 1998, and evidently from 1998 to 1999, cited above, the lower bounds of the projection cones decline just rapidly enough to envelop the expected numbers of teenage homicide offenders for these two years.
|
From page 343... ...
also imply slow increases in teenage homicide offending rates. Then it clearly is the case that the Steffensmeier and Harer forecasts would fall well within the upper and lower projection series exhibited in Figures B-6 and B-7.
|
From page 344... ...
forecast lies in the upper regions of the projection cones of Figures B-6 and B-7. Thus, his 1997 forecasts are not entirely implausible, but, in view of the apparent continuing declines in homicide in 1997 and 1998, perhaps not as plausible as forecasts that fall further within our upper and lower bounds projection series.
|
From page 345... ...
and, accordingly, that the annual numbers of teenage homicide offenders will again increase in the 1998-2007 period cannot be entirely ruled out. Our exercise in forecasting juvenile homicide offenders also illustrates two additional implications of uncertainty in forecasts of crime rates and offenders.
|
From page 346... ...
Land 1987 Age structure and crime: Symmetry versus asymmetry and the projection of crime rates through the l990s. American Sociological Review 52~170-183~.
|
From page 347... ...
Washington, DC: Bureau of Justice Statistics. 1997 Update on Trends in Juvenile Violence: A Report to the United States Attorney General on Current and Future Rates of Juvenile Offending.
|
From page 348... ...
1973 Age composition and the increase in recorded crime. Criminology 11~1~:61-70.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.