The Limits of Crime Data for Predicting Confinement Space

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The Limits of Crime Data for Predicting
Confinement Space
"Prediction is very difficult, especially if it's
about the future." Nils Bohr Nobel laureate in
Physics
Jeffrey A. Butts, Ph.D.December 2002 A product
from the Urban Institutes Program on Youth
Justice
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The Dangers of Predicting Space Needs with
Crime Data
1987
Many juvenile justice agencies predict their
future needs for confinement space by analyzing
recent trends in serious juvenile crime. What
could be wrong with this?
Using arrests for Violent Index crimes (murder,
rape, robbery, and aggravated assault) as a proxy
for incarceration need, an analyst in 1987 would
have predicted no changes in the demand for
confinement space. Would this have been an
accurate prediction?
An examination of national data about juvenile
violent crime arrests will illustrate the
point. Source All arrest data are from an Urban
Institute analysis of data from the FBI Uniform
Crime Reporting Program and the publication,
Crime in the United States (series, 1975-2001).
x
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The Dangers of Predicting Space Needs with
Crime Data
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The Dangers of Predicting Space Needs with
Crime Data
1994
By 1994, the number of juveniles arrested for
Violent Index Crimes nationwide nearly
doubled. If decision-makers had listened to the
analyst in 1987, they would have severely
under-estimated the potential demand for space.
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The Dangers of Predicting Space Needs with
Crime Data
1994
On the other hand, what if another analyst was
asked to predict the need for secure confinement
space based upon crime trends as we knew them in
1994?
The second analyst, working in 1994, would have
encouraged policymakers to fund a vast expansion
of confinement space to accommodate a growing
number of serious, young offenders.
x
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The Dangers of Predicting Space Needs with
Crime Data
How successful would this prediction be seven
years later?
x
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The Dangers of Predicting Space Needs with
Crime Data
x
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The Dangers of Predicting Space Needs with
Crime Data
2001
By 2001, much of the new confinement capacity
called for in 1994 would have been under-used, or
worse, used inappropriately.
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Most Offense Types Showed the Same Pattern in
Recent Years
x
The problem would be similar no matter which
offenses were used by crime data analysts.
Using crime trends to anticipate long-term
demands for secure confinement space is very
risky.
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Most Offense Types Showed the Same Pattern in
Recent Years
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Most Offense Types Showed the Same Pattern in
Recent Years
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Most Offense Types Showed the Same Pattern in
Recent Years
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Most Offense Types Showed the Same Pattern in
Recent Years
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Most Offense Types Showed the Same Pattern in
Recent Years
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Most Offense Types Showed the Same Pattern in
Recent Years
Burglary is a big exception nationally. The
general trend has been down for juvenile burglary
arrests. Does this mean that we should be
building less capacity?
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Demand for Space is Shaped by How Confinement
Space is Used
The answer to that question depends on how
current confinement capacity is used If
burglary cases account for a large portion of
confined juveniles, then the downward trend in
burglary arrests will reduce demand.
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Demand for Space is Shaped by How Confinement
Space is Used
How do we use current confinement capacity? The
Department of Justice asked the States this
question in 1997.
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States Vary Greatly in How They Use Secure
Juvenile Confinement Space
These data represent all juveniles being confined
in residential facilities for delinquency
offenses on a particular day in 1997. Source
Snyder, Howard and Melissa Sickmund (1999).
Juvenile Offenders and Victims 1999 National
Report. Washington, DC Office of Juvenile
Justice and Delinquency Prevention.
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States Vary Greatly in How They Use Secure
Juvenile Confinement Space
Note the variations in how confinement capacity
is used These States also vary greatly in the
sheer numbers of youth locked up for delinquency
offenses.
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States Vary Greatly in How They Use Secure
Juvenile Confinement Space
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States Vary Greatly in How They Use Secure
Juvenile Confinement Space
Juveniles in confinement per 100,000
Even when we control for the number of youth in
the population, States vary greatly in how they
use secure confinement space. Obviously, the use
of secure confinement is not simply a function of
juvenile populations and juvenile crime rates.
Numbers in parentheses are youths in placement.
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States Vary Greatly in How They Use Secure
Juvenile Confinement Space
Juveniles in confinement per 100,000
Numbers in parentheses are youths in placement.
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So, What is the Answer?

• There will never be a simple, statistical
  solution to uncertainty about space needs
• Population data, arrest data juvenile court
  data are insufficient for projecting future
  needs for confinement space
• Understanding the demand for secure confinement
  requires information about laws, policies,
  juvenile justice practices

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So, What is the Answer?
The best way for State and local jurisdictions to
deal with uncertainty about the future demand for
secure confinement space is to engage in a
routine process of forecasting and that
process must include policymakers and
practitioners, not only data analysts and
researchers.
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For More Information
The Program on Youth Justice
URBAN INSTITUTE Justice Policy Center
2100 M Street, NW Washington, DC 20037
Practical Forecasting Web Site http//youth.urban.
org
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For More Information
"To expect the unexpected shows a thoroughly
modern intellect. " Oscar Wilde