Aggression and Bullying

Aggression and Bullying
1
 
 
 
 
 
 
 
 

Preventing Childhood Aggression and Bullying: Implications for
School-Based Intervention Research from the Denver Public Schools Trial


Jeffrey M. Jenson, Ph.D.
University of Denver
Denver, Colorado

William A. Dieterich, Ph.D.
Northpointe Institute for Public Management
Golden, Colorado





October 5, 2009





 
 
 
 
 
 
This manuscript was presented at the Los Angeles Conference on Intervention Research in
Social Work. School of Social Work, University of Southern California. Los Angeles, CA.
October 23, 2009.

---

Aggression and Bullying
2
 
 
Abstract

Outcomes from a group-randomized trial of a prevention curriculum aimed at preventing
bullying and victimization among elementary students in the Denver, Colorado public school
system are presented. Twenty-eight elementary schools were randomly assigned to receive
selected modules of Youth Matters, a skills-training curriculum that targets bullying and
victimization, or to a no-treatment control group. Linear growth models were fitted to four waves
of data collected over two years to test the effect of the intervention on the rate of change in self-
reported bullying and victimization. Participation in Youth Matters was associated with a 20
percent decline in bully victimization at the end of the fourth-grade. Practice and methodological
challenges encountered in the investigation are discussed in the larger context of intervention
research in school settings. Strategies to increase school-based intervention research by social
work investigators are outlined.

Keywords: children, adolescents, bullying, victimization, prevention

---

Aggression and Bullying
3
 
 
School-based prevention has been heralded as an efficacious and cost-effective way to
decrease the prevalence of childhood and adolescent antisocial behavior (Aos, Lieb, Mayfield,
Miller, & Pennucci, 2004; Gottfredson & Wilson, 2003; Hawkins, 2006). Bolstered by evidence
indicating that empirically-based curricula can prevent or delay the onset of problems like drug
use or delinquency, many schools have strengthened their commitment to providing prevention
content at all educational levels (Jenson, in press). Smoking, illicit drug use, delinquency, and
health concerns have been common targets of school-based prevention efforts.
In recent years many school districts have also placed financial resources into developing
and evaluating prevention programs aimed at reducing bullying and bully victimization
(Eisenberg & Aalsma, 2005; Jenson, Dieterich, Rinner, Washington, & Burgoyne, 2006; Rigby,
Smith, & Pepler, 2004; Spivak & Prothrow-Stith, 2001). The rather sudden interest in bullying
prevention was fostered by a series of school shootings that shook the foundation of American
public education in the past decade. Close examination of the incidents of school violence
revealed that many perpetrators had been victims of bullying or exclusionary peer practices
during childhood and early adolescence (Vossekuil, Fein, Reddy, Borum, & Modzeleski, 2002).
These developments, along with the positive outcomes reported in studies of anti-bullying
programs in Norway (Olweus, 1993, 1994) and other European countries (Smith, Pepler, &
Rigby, 2004), has created considerable interest in bullying prevention programs in many
American public school systems.
Prevalence and Nature of Bullying
The word “bullying” is derived from the English language and generally refers to a social
process in which a child or an adolescent exerts power or influence over another student in a
negative manner to achieve a desired effect or outcome. Olweus (1993) and other investigators

---

Aggression and Bullying
4
 
 
(Frey, Hirschstein, Snell, Edstrom, MacKenzie, & Broderick, 2005; Smith & Brain, 2000) note
that bullying occurs in physical, social, and emotional contexts and varies considerably in
severity. Overt forms of bullying generally take the form of actual or intended physical harm.
Conversely, relational patterns of bullying are most often characterized by social practices that
exclude students from desirable peer groups or activities. The concept of a power imbalance in
which the perpetrator exerts influence over a victim is an important component and emotional
dynamic of bullying (Olweus, 1993; Smith, Morita, Junger-Tas, Olweus, Catalano, & Slee,
1999).
Prevalence estimates of bullying reveal that approximately 30 percent of students engage
in overt or relational bullying or are victims of bullying during elementary school (Juvonen,
Graham, & Schuster, 2003; Nansel, Overpeck, Pilla, Ruan, Simons-Mortin, & Scheidt, 2001;
Pellegrini, Bartini,& Brooks, 2001). Students are most likely to be bullied in the classroom or on
the playground (Fekkes, Pijpers, & Verloove-Vanhorick, 2005). Boys commit overt or physical
acts of bullying at higher rates than girls (Baldry & Farrington, 2000; Nansel et al., 2001).
Conversely, girls are more likely than boys to be involved in relational forms of bullying such as
excluding others from social activities or spreading rumors (Nansel et al., 2001; Olweus, 1994).
Reports of racial or ethnic differences in self-reported rates of bullying behavior and
victimization have yielded inconsistent results. Nansel and colleagues (2001) found that African
American youth were bullied significantly less often than Caucasian or Latino/a youth. Other
investigators have reported lower self-reported victimization rates among Latino/a student when
compared to all other racial and ethnic groups (Graham & Juvonen, 2002; Hanish & Guerra,
2000). Bullying tends to peak between the ages of 11 and 13 or at about the period of transition
from elementary to secondary school (Smith, Madsen, & Moody, 1999).

---

Aggression and Bullying
5
 
 
Researchers and practitioners speak generally of bullying as a phenomenon that involves
complex interactions between bullies, victims, bully-victims, and bystanders. Longitudinal
studies of bullying suggest that bullies and victims are at elevated risk for later mental health
problems and involvement in antisocial conduct (Hawker & Boulton, 2000; Olweus, 1993;
Roland, 2002). Both bullies and victims experience elevated levels of depression during
adolescence (Forero, McLellan, Rissel, & Bauman, 1999). Bullies participate in other types of
aggressive, deviant, and criminal behavior at higher rates than victims (Sourander, Helstela,
Helenius, & Piha, 2000), while victims are more likely than bullies to report feelings of
insecurity, low self-esteem, and anxiety (Bond, Carlin, Thomas, Rubin, & Patton, 2001; Forero
et al., 1999). Victimization is associated with poor academic performance in several studies
(Eisenberg, Neumark-Sztainer, & Perry, 2003; Juvonen, Nishina, & Graham, 2000). Evidence
suggests that youth who both bully and are bullied by other students exhibit the poorest
psychological and social outcomes (Austin & Joseph, 1996; Juvonen et al., 2003).
Bullying Prevention Approaches
Prevention programs have used school-wide (Olweus, 1993), classroom management
(Roland & Galloway, 2002), peer support (Cowie & Wallace, 2000), playground aggression
reduction (Cunningham, Cunningham, Martorelli, Tran, Young, & Zacherias, 1998; Frey et al.,
2005) and cognitive-behavioral (Jenson & Dieterich, 2007) strategies to reduce bullying behavior
and victimization. Olweus (1993) is generally credited with developing the first efficacious anti-
bullying program. The Olweus Bullying Prevention Program was created in response to several
youth suicides in Norway during the early-1980s in which bullying appeared to play a major
cause. The program is a school-wide approach that has been tested using age-cohort designs in
Norway. The strategy raises attention to school bullying by involving students, teachers, and

---

Aggression and Bullying
6
 
 
other school personnel in efforts to change the climate and values associated with bullying
(Limber, 2004).
Farrington and Ttofi (in press) recently reviewed the efficacy of 30 bullying prevention
programs and found that bullying behavior among students in schools with anti-bullying
interventions was approximately 23 percent less than control group schools. Of the 30 programs
reviewed by Farrington and Ttofi (in press), 12 interventions were considered effective, 10 were
labeled as probably effective, and eight yielded no positive effects on bullying or victimization.
Only nine of the 30 studies reviewed were randomized experiments. Parent training, playground
supervision, school conferences, disciplinary practices, videos, and classroom management
approaches were associated with reductions in bullying. Program elements that emphasized
cooperative group work, skill training, peer interventions, parent training, and multimedia
strategies were associated with a decrease in victimization. In general, school-wide interventions
targeting school and classroom norms about aggression had a greater effect on reducing bullying
(e.g., Olweus, 2004) while skill training and other individual-focused interventions had a greater
effect on reducing victimization (e.g., Jenson & Dieterich, 2007).
The limited evidence to support or repute the efficacy of anti-bullying interventions in
public schools argues for additional intervention research aimed at preventing or reducing
bullying and victimization. In the present study, we report outcomes from a group-randomized
trial assessing the effects of a skills-based curriculum targeting bullying and bully victimization
among elementary school students in a large, urban school district. The Youth Matters (YM)
program was tested under controlled conditions in 28 public elementary schools in Denver,
Colorado. We present time 4 results detailing the effects of the curriculum on self-reported
bullying and bully victimization of fourth- and fifth-grade students. Program and methodological

---

Aggression and Bullying
7
 
 
lessons learned from the YM trial are discussed and implications for school-based intervention
research are noted.
The Denver Public Schools Youth Matters Prevention Trial
Intervention Elements
The YM program promotes the healthy development of young people by encouraging
positive relationships between students and school adults and promoting safe and healthy norms
throughout the school community. The curriculum consists of a series of instructional modules
that address issues (topics) and skills important to students and their school community. Each
module includes a 30-40 page story that is designed to help schools meet academic standards in
both health education and language arts. The substantive content of each story is directly linked
to skills taught in the curriculum modules. To address systemic issues associated with bullying,
modules conclude with the development of classroom or school-wide projects that demonstrate
the adverse consequences of bullying and aggression to students.
The YM curriculum aims to enhance student’s emotional regulation skills in an attempt
to prevent or respond appropriately to bullying. As shown in Figure 1, skill modules emphasize
social competency and social resistance skills (e.g., asking for help, making better choices,
standing up for yourself and others, preventing bullying behaviors, coping with bullying, etc.)
that students can use to stay out of trouble, build positive relationships, make good decisions, and
avoid antisocial behavior. In issue modules, students discuss critical developmental concerns
(e.g., being a good friend, teasing and bullying, building empathy, risks and norms surrounding
aggression, etc.) and create projects that promote positive norms in school. Instructional
materials in the issue modules are intended to strengthen peer and school norms against

---

Aggression and Bullying
8
 
 
antisocial behaviors. Understanding the consequences of bullying from both a bully and victim
perspective is emphasized.
Insert Figure 1 about here
Four YM curriculum modules were implemented and tested in grades four and five over
the course of two academic years. Grades four and five were selected based on an appropriate fit
between developmental ability and curricula content and on evidence suggesting that bullying
tends to peak in the upper grades of elementary school (Nansel et al., 2001). In addition, grade
five marks the transition year prior to middle school enrollment in the district and was identified
by school administrators and teachers as a pivotal intervention period for students. Curriculum
modules were translated into Spanish for use in the three Spanish speaking classrooms included
in the investigation.
Theoretical Foundation
The YM curriculum is guided by theoretical constructs outlined in the social development
model [SDM] (Catalano & Hawkins, 1996). The SDM integrates perspectives from social
control theory (Hirschi, 1969), social learning theory (Bandura, 1989), and differential
association theory (Sutherland, 1973; Matsueda, 1982). The theory proposes that four factors
inhibit the development of antisocial behaviors in children: 1) bonding, defined as attachment
and commitment to family, school and positive peers (Garmezy, 1985); 2) belief in the shared
values or norms of these social units; 3) external constraints such as clear, consistent standards
against antisocial behavior (Hansen, Malotte, & Fileding, 1988; Scheier & Botvin, 1998); and 4)
social, cognitive and emotional skills that provide protective tools for children to solve problems
(Rutter, 1985), assertively and confidently perform in social situations (Werner and Smith,
1982), and resist influences and impulses to violate their norms for behavior (Hansen, Graham,

---

Aggression and Bullying
9
 
 
Sobel, Shelton, Flay, & Johnson, 1987). Curriculum sessions addressed each of these four core
areas. Additional information about the SDM is found in Catalano and Hawkins (1996).
Procedures
The sampling frame for the study consisted of fourth-grade classrooms at 40 Denver
elementary schools. Schools were selected by the school district on the basis of risk criteria that
included expulsion rates, suspension rates, and the percentage of students eligible for the free
lunch program. A decision was made to limit the initial sampling frame to 40 of the 72
elementary schools in order to target those schools with the highest rates of problem behavior.
The 40 schools were stratified by geographic region in the city and risk criteria and then
randomly assigned to either the control or experimental condition. Fourteen of the 20 schools in
each study condition agreed to participate resulting in a total of 28 schools.
Participants
We attempted to consent 674 eligible students in the control schools. Sixty-eight percent
of youth in the control group schools consented, 16 percent declined, and 16 percent did not
return the consent. Thus, at baseline the control group contained 462 consented students. In the
experimental schools we attempted to consent 928 eligible students. Of those attempts, 76
percent consented, 11 percent declined, and 14 percent did not return the consent. The
experimental group contained 702 consented students at baseline. Forty-nine percent (N = 328)
of students in the experimental group were female compared to 53 percent (N = 242) in the
control group. Males accounted for 51 percent (N = 342) and 47 percent (N = 214) of subjects in
the experimental and control groups respectively. Sixty-five percent (N = 433) of subjects in the
experimental group were Latino/a, 13 percent (N = 88) were African American, 14 percent (N =
94) were American Indian, Asian American, or mixed race/ethnicity, and 8 percent (N = 55)

---

Aggression and Bullying
10
 
 
were Caucasian. Fifty-one percent (N = 233) of subjects in the control group were Latino/a, 21
percent (N = 95) were American Indian, Asian American, or mixed race/ethnicity, 17 percent (N
= 78) were African-American, and 11 percent (N = 50) were Caucasian. Students in the sample
study were similar to other students in the school district with regard to gender and ethnicity.
Measures
Student data were collected through classroom surveys conducted in the fall and spring
semesters of each academic year. Study outcomes used in the current analysis were bully
victimization and bullying behavior. Bully victimization was measured by the bully victim scale
from the Revised Olweus Bully/Victim Questionnaire (Olweus, 1996). The scale items are
prefaced by the statement “Have you been bullied since the beginning of the school year in one
or more of the following ways?” The scale consists of the following items: (1) I was called mean
names, made fun of or teased in a hurtful way, (2) Other students kept me out of things on
purpose, excluded me from their group of friends or completely ignored me, (3) I was hit,
kicked, pushed, or shoved around, (4) Other students spread false rumors about me and tried to
make others dislike me, (5) I had money or other things taken from me or damaged, and (6) I
was threatened or forced to do things I didn’t want to do. The items were coded as follows: 1 = It
hasn’t happened since the beginning of the school year, 2 = Only once or twice, 3 = 2 or 3 times
a month, 4 = About once a week, and 5 = Several times a week. The follow-up version of this
scale is identical except that the time frame is defined as “in the past month.” A bully victim
scale score was calculated by summing the items and dividing by the number of non-missing
items, using a threshold of a minimum of four non-missing items to obtain a valid scale score.
The Cronbach’s alpha coefficient for this scale is .81.

---