Boys who end up being convicted of homicide do not become
killers by accident or as a result of a random set of circumstances. Instead,
they follow developmental pathways that lead them to commit the ultimate crime,
according to the latest research to emerge from the Pittsburgh Youth Study,
which more than two decades ago began following the lives of 1,517 boys who
attended Pittsburgh’s public schools.
Moreover, researchers identified certain negative early life
experiences shared by the 37 boys who became convicted homicide offenders,
which now makes it possible to predict those most likely to commit murder with
greater accuracy than ever before. They also found that boys who fell victim to
homicide and boys who were arrested on homicide charges, but not convicted,
also tended to follow distinctive pathways to such outcomes.
Recent findings of the Pittsburgh Youth Study shed new light
on how boys in urban settings become homicide offenders and murder victims,
including influential risk factors, such as being raised in a broken home,
having a young mother, living in a bad neighborhood, and committing serious delinquent
acts at an early age—knowledge that can help determine who is most at risk and
how best to intervene to divert them from the path that leads to murder.
The Pittsburgh Youth
The Pittsburgh Youth Study began in 1987 as a long-term
examination of developmental pathways among at-risk boys and the roots of
delinquency. It was one of three such projects started with funding from the
U.S. Department of Justice Office of Juvenile Justice Delinquency Prevention.
The other sites are in Denver, Colo. and Rochester, N.Y.
Each study is a longitudinal investigation involving repeated
assessments with the same juveniles and their parents or primary caretakers
throughout the boys÷ developmental years and beyond. The approach allowed
investigators to more accurately determine when a boy first engaged in disruptive
behaviors and to examine the possible causes, frequency, severity, and other
In Pittsburgh, investigators began by contacting more than
3,000 randomly selected boys in the Pittsburgh Public Schools who were enrolled
in grades 1, 4 and 7. They used a screening assessment of each boy, his primary
caretaker, and a teacher to gather retrospective data on the boys’ disruptive
and delinquent behaviors. To increase the number of high-risk boys, the 30
percent who were determined to be the most antisocial were included in the
study sample and another 30 percent were randomly selected from the remaining
group. In all, 1,517 boys ranging in age from 7 to 13 years old were selected
across the three grade cohorts to receive follow-up assessments.
More than 57 percent of the youngest and oldest boys in the
study were African American, as were 56 percent of the middle-aged boys. The
rest were Caucasian. The percentage of boys who had been held back in school
ranged from 39.4 percent of the oldest cohort to 26.3 percent of the youngest
at the beginning of the study. More than 95 percent of the youngest cohort of
boys, 92.2 percent of the middle-aged boys, and 94 percent of the oldest cohort
lived with their natural mother. The percentage of boys living in a household
that included their natural father ranged from 37.1 percent to 41.5 percent.
Assessments were initially conducted in 6-month intervals.
Later, they were done annually. Investigators to date have done an estimated
50,000 assessments, most of which were face-to-face interviews. Archival data
from sources such as school and court records were also gathered.
Participation among the boys and their primary caretakers
was high, ranging from 84 percent to 86 percent across the three grade cohorts.
Pathways to Violence
The Pittsburgh Youth Study and its sister studies in Denver
and Rochester have produced a body of research that contributes substantially
to the understanding of delinquent behavior, particularly the onset of
delinquency and violence.
One of the most significant findings is that delinquency and
violence are the result of a gradual developmental process that occurs over
many years. Contrary to popular perceptions that serious criminal offenders are
psychopaths who act unpredictably, the Pittsburgh Youth Study found that
serious offending in some ways is predicable. Investigators reported that there
are developmental pathways—remarkably orderly progressions—that tend to lead
young boys to delinquency and violence.
The Pittsburgh Youth Study has presented evidence that there
is not one, but three of these developmental pathways. Investigators defined,
for example, what they call an Authority Conflict Pathway, which starts with
stubborn behavior before age 12, progresses to defiance and then to authority
avoidance, such as truancy. A second, Covert Pathway, is a step-by-step
progression in which a boy begins with minor covert acts before age 15, moves
to property damage, then to moderate delinquency and, finally, to serious
A third, Overt Pathway, is particularly relevant to the
recent research on young homicide offenders and their victims. Boys who follow
this pathway start with acts of minor aggression, progress to gang fighting and
physical fighting, then graduate to more severe acts of violence, including
Young Homicide Offenders
Researchers did not intend to focus specifically on boys who
become homicide offenders when the Pittsburgh Youth Study began. They did not,
however, anticipate the scope of tragedy they would encounter while following
1,517 inner-city boys into early adulthood.
Over the course of more than two decades, 39 of the boys
became victims of homicide, 37 were convicted of homicide, and another 33 were
arrested for homicide, but not convicted.
"That was terribly unexpected. We had no idea that we would
have so many killings," said Pittsburgh Youth Study Principal Investigator Rolf
Loeber, PhD, professor of psychiatry, psychology, and epidemiology at the
University of Pittsburgh. “When the killings happened, we knew the individuals.
We knew to what extent they had encountered difficulties in life, what kind of
school career they had, their family background, their psychopathology. All of
this information was collected without knowing that these individuals would
kill or be killed.”
Having gathered data on the boys throughout their development
was particularly important when examining the victims of homicide, Dr. Loeber
said. ”Most studies don’t have information on the background of the victims. To
reconstruct their lives is very hard after they are killed. You have to rely on
relatives, friends. But there are more than 50 risk and protective factors that
predict violence. It is very difficult to reconstruct them by just talking to a
Researchers examined data on a wide range of factors
gathered from interviews with the boys and their caretakers and from other
sources. They examined three classifications of risk factors:
- Criminal risk factors, which included
self-reported and court records of prior violent, property, drug and other
offenses, such as robbery, aggravated assault, carrying a weapon, vehicle
theft, receiving stolen property, selling drugs and minor fraud.
- Explanatory factors, which are factors that do
not measure antisocial behavior. They include having a young mother, family on
welfare, lack of guilt, a mother who is unemployed, living in a bad
neighborhood, and being raised in a broken family.
- Behavioral risk factors, which are factors that
reflect anti-social behavior. They include factors related to attitude, such as
truancy, school suspension, having a positive attitude to delinquency,
disruptive behavior disorder, and having delinquent peers.
Convicted Homicide Offenders
Researchers had a number of questions in mind when they set
out to examine the data on boys who ended up being convicted of homicide. For
example, to what extent did they engage in antisocial and delinquent behavior
early in childhood? To what extent can convicted homicide offenders be
predicted based on a combination of criminal, explanatory and behavioral risk
factors? Is there a dose-response relationship between the number of risk
factors experienced and the chances of becoming a convicted homicide offender?
Several studies suggest that most homicide offenders were
violent early in life and committed many other crimes. The boys convicted of
homicide who participated in the Pittsburgh Youth Study were no exception.
The strongest predictor of young homicide offenders was
prior criminal or delinquent acts. Researchers examined both self-reported
offenses and records of delinquency convictions up to age 14 and found that
violent offenses were the most prevalent.
Among boys later convicted of homicide, 76 percent reported
having carried a weapon and 62 percent reported participating in gang fighting,
aggravated assault, or robbery. The study also found that being convicted of
different types of violent offenses, including aggravated assault and weapons
charges, was a stronger predictor of later homicide offending than
One unexpected finding was that several types of property
crimes committed up to age 14 also strongly predicted later homicide
conviction, which suggests the boys were already versatile criminal offenders
who engaged in a variety of delinquent acts before they committed murder.
Several types of self-reported substance use, such as hard drugs and alcohol,
did not significantly predict a later homicide conviction—a finding that also
ran contrary to expectations.
When criminal risk factors obtained from all sources were
considered, arrests on simple assault and weapons charges, self-reported weapon
carrying, conspiracy convictions (a rather larger category of offenses), and
self-reported minor fraud emerged as significant independent predictors of
later homicide conviction.
Researchers constructed a criminal risk score based on those
risk factors and found that 59 percent of the boys later convicted of homicide
had at least three of the five risk factors.
Among explanatory risk factors, nine were found to significantly
predict convicted homicide offenders. Living in a broken home, for example, was
the most prevalent with 89 percent of convicted homicide offenders having
experienced a broken home, compared to 62 percent of the study controls. The
study also reports that 71 percent of convicted homicide offenders were raised
in a family on welfare, and 65 percent lived in a bad neighborhood. Other
important explanatory risk factors were having a young mother, being old for
their grade in school, having an unemployed mother, lack of guilt, low
socioeconomic status, having a father with behavioral problems, and hyperactivity-impulsivity-attention
Researchers also measured 19 behavioral factors and found
that 11 significantly predicted convicted homicide offenders. The strongest
predictor was having been suspended from school. Among boys later convicted of
homicide, 78 percent had at least one school suspension. Other behavioral risk
factors experienced by more than half of the boys who became convicted homicide
offenders were having a positive attitude toward delinquency, disruptive
behavior disorder, and serious delinquency.
Predicting Convicted Offenders
Researchers analyzed all of the significant, independently
predictive explanatory, behavioral, and criminal risk factors in a final
exercise to predict convicted homicide offenders. The boys experienced all of
the factors before they turned 14 years of age.
The best predictors were determined to be the following:
- Prior delinquent acts—specifically, a conspiracy
conviction, simple assault arrest, and self-report weapons carrying.
- An attitude that favors delinquency.
- Having a young mother.
- Having been suspended from school.
- And living in a bad neighborhood as defined by
U.S. Census data.
This integrated analysis presented further evidence that a
range of risk factors best predicts boys who are most likely to commit murder
and that the more risk factors a boy experiences, the greater the probability
he will become a convicted homicide offender. For example, having at least four
of the seven risk factors identified 62 percent of the boys convicted of
Researchers note the results may overestimate the true ability
to predict homicide offenders largely because the risk scale was built and
tested on the same participants. However, the findings suggest that determining
whether boys have experienced four or more of the most-predictive risk factors
might be a useful way to predict those well down the path to murder.
Previous studies suggest that African American boys are more
likely to be convicted of homicide than Caucasian boys. In the Pittsburgh Youth Study, 86 percent of
the boys convicted of homicide were African American, while African American
boys accounted for 54 percent of the study’s control sample.
Researchers found, however, that race itself did not predict
convicted homicide offenders. Instead, the racial differences in the prevalence
of convicted homicide offenders were largely the result of significant racial
differences in early risk factors that predicted later homicide convictions.
For example, 81 percent of the study’s African American boys lived in broken
homes, compared to 42 percent of Caucasian boys. Being raised in a family on
welfare was an experience shared by 61 percent of African American boys,
compared to 23 percent of Caucasian boys. And 65 percent of African American
boys lived in a bad neighborhood, compared to 32 percent of Caucasian boys.
Boys who became victims of homicide resembled those who
became convicted homicide offenders. The study reports that risk factors found
to strongly predict homicide victims tend to be similar to those that strongly
predict boys who became convicted homicide offenders.
Researchers found that of the significant risk factors that
predicted convicted homicide offenders, 71 percent were also significant
predictors of homicide victims. For example, early offending strongly predicted
homicide victims, just as it did with convicted offenders. In the Pittsburgh
study, 56 percent of homicide victims had been arrested and 44 percent had been
convicted by age 14. The most common offenses committed early in the lives of
those victims included vehicle theft, aggravated assault, receiving stolen
property, drug offenses, and conspiracy.
The results showed other similarities. The study found that
homicide offenders did not grow up more deprived or exposed to more risk factors
than homicide victims, although certain explanatory factors were stronger
predictors for one group than they were for the other. For example, the
strongest predictors for convicted homicide offenders were mostly socioeconomic
factors, such as a broken home and a family on welfare, while the strongest
predictors for victims were mostly individual, including a lack of guilt, and
school-related factors, such as low achievement, being old for their grade, and
Another important conclusion about shared characteristics
between homicide offenders and homicide victims was that violence appeared to
evolve from disputes related to illegal activities, such as the drug trade, the
trade in stolen goods, robbery to obtain drugs and/or money, or other illegal
property transactions. The authors concluded that it is likely that reductions
in these illegal activities may reduce conflict and ensuing violence and
The Pittsburgh Youth Study stands as the first prospective
longitudinal study of homicide victims. Its limitations include the fact that
the Pittsburgh numbers were modest and the Pittsburgh results may not be generalized
to the nation. Nevertheless, researchers reported that the explanatory and
behavioral risk factors they measured significantly predicted homicide victims
up to 22 years later. And in most analyses, homicide victims were predicted
just as accurately as convicted homicide offenders.
Implications for Interventions
The Pittsburgh Youth Study shows that homicide offenders and
victims are the product of a series of causes that unfold over time and offers
new insights into those causes that are useful in determining how best to
intervene to prevent them from taking such a destructive course.
Research suggests, however, that preventive interventions do
not guarantee success. In a study that involved Pittsburgh Youth Study
participants, for example, researchers looked at whether homicide offenders
used more mental health services or school services, such as special education
and classes for behavioral problems, than violent offenders who crimes did not
include murder. They found that about two-thirds of homicide offenders had
received help for behavioral problems when they were young—a rate significantly
greater than what was found among other violent offenders.
In that study, however, it was not possible to determine the
precise nature of the services, or to assess the quality of services or whether
they were based on empirically verified interventions.
Pittsburgh Youth Study researchers argue that empirical
knowledge about what works, and knowledge of the causes of homicide offending,
is necessary to determine the optimal timing and the effectiveness of
preventive interventions and in providing the basis for screening young people
to determine their risk of becoming homicide offender or victims.
In one exercise, they used the Pittsburgh Youth Study cohorts
to examine the possible effects that changing one aspect of an individual’s
problem behavior might have on the national male homicide rate. The exercise
used data from the youngest and oldest cohorts of boys and was based on
implementation of three well-evaluated early prevention interventions: the Olds
Nurse Home Visitation Program, which provides in-home services to families
around the birth of the child and during infancy; the Perry Preschool Program,
which provides early childhood education to at-risk families; and multisystemic
therapy (MST) for violent juvenile offenders, which works with adolescent
offenders who have already shown evidence of delinquency.
The results suggest that effective intervention has the potential
to save lives and reduce the financial costs associated with homicide, such as the expense of imprisoning convicted offenders. For
example, if implemented nationally:
- The Nurse Home Visitation program with at-risk
families by itself might prevent nearly 22 percent of all homicides in the
United States. In cost-savings alone, this would amount to some $3.5 billion.
- The Perry Preschool Program for preschoolers
could potentially reduce homicides by up to 24 percent, saving about 3,000
lives a year and nearly $4 billion in incarceration costs.
- MST for juvenile delinquents by itself would
reduce homicides, but only by 6 percent.
“One of the most
significant findings [of the Pittsburgh Youth Study] is that the idea of
developmental pathways from less problematic behavior to much more serious behavior
is not random—that, for the majority of cases, it is systematic,” Dr. Loeber
said. “The take-home message is: If we want to reduce the overall level of
victimization in society, or a city like Pittsburgh, it is much more effective
to start early in life rather than waiting for individuals to be violently
victimized or killed.” At the same time, it is necessary to deal with the
current generations of violent individuals and their potential victims. It
seems probable that reducing illegal economic activities will reduce disputes
and violent solutions.
R., & Farrington, D.P. (2011). Young Homicide Offenders and Victims: Risk
Factors, Prediction, and Prevention from Childhood. New York: Springer
Publications, written by O.B.E., professor of psychological criminology at
This Special Report is
based on the above-referenced publications. It is not intended to be an
original work but a summary for the convenience of our readers. References
noted in the text follow:
R., Lacourse, E., & Homish, D. L. (2005). Homicide, violence and
developmental trajectories. In R. E. Tremblay, W. W. Hartup, & J. Archer
(Eds.), Developmental origins of aggression (pp. 202–220). New York: Guilford.
L. M., Daday, J. K., Crandall, C. S., Sklar, D. P., & Jost, P. F. (2006).
Exploring demographic, structural, and behavioral overlap among homicide offenders
and victims. Homicide Studies, 10, 155–180.
for Disease Control (2008, Summer). Youth violence. Facts at a glance. Atlanta,
GA. Center for Disease Control. www.cdc.gov/injury.
M., Creemers, J., Loeber, R., Homish, D. L., & Wei, E. (2001). Juvenile justice
and mental health interventions for juveniles who eventually commit homicide.
Paper presented at the meeting of the American Society of Criminology, Atlanta,