Evaluation of two interventions to reduce aggressive and antisocial behavior in first and second graders in a resource-poor setting

International Journal of Educational Research 48 (2009) 307–319

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International Journal of Educational Research journal homepage: www.elsevier.com/locate/ijedures

Evaluation of two interventions to reduce aggressive and antisocial behavior in first and second graders in a resource-poor setting§ Joanne Klevens a,*, Jose´ William Martı´nez b, Brenda Le a, Carlos Rojas c, Adriana Duque d, Rafael Tovar e a

Centers for Disease Control and Prevention, Atlanta, GA, USA Universidad Tecnolo´gica de Pereira, Pereira, Colombia c Universidad de Antioquia, Medellı´n, Colombia d Fundacio´n Universitaria del A´rea Andina, Pereira, Colombia e Universidad del Valle, Cali, Colombia b

A R T I C L E I N F O

A B S T R A C T

Article history: Received 3 March 2009 Received in revised form 11 January 2010 Accepted 25 February 2010

We conducted a three-arm cluster randomized controlled trial (n = 2491) to evaluate a teacher delivered intervention to reduce aggressive and antisocial behavior and increase prosocial behavior in the classroom. A second aim of this trial was to establish whether combining this intervention with an intervention for parents was better than the teacheronly intervention. This evaluation was conducted in a resource-poor setting (Pereira, Colombia). The findings show that both interventions prevented increases in aggressive and antisocial behavior. However, the teacher-only intervention also had a positive impact on increasing prosocial behavior. Published by Elsevier Ltd.

Keywords: Classroom Prevention Intervention Teaching practices Disruptive behavior

1. Introduction Studies conducted in various countries show that childhood aggression and antisocial behavior increase a child’s risk for multiple negative developmental outcomes including substance abuse, delinquency, violence and crime (Broidy et al., 2003; Farrington & Loeber, 2000; Huesmann, Eron, & Dubow, 2002). Reviews of the literature have identified many factors (e.g., genetics, sex, prenatal exposures, perinatal complications, temperament, ineffective parenting, poverty, lack of commitment to school, academic failure, peer influence, exposure to violence) that interact and contribute to the development of aggressive and antisocial behavior in children (Burke, Loeber, & Birmaher, 2002; Farrington, 2005; Hawkins et al., 1998; U.S. Department of Health and Human Services, 2001). Although factors such as sex are helpful in identifying those at higher risk, efforts to prevent problems should be designed to reduce modifiable risk factors and/or promote protective factors (Mercy & O’Carroll, 1988). Modifying risk behaviors and factors early on can prevent a child from following a negative developmental pathway that can result in peer rejection, poor school performance, school drop-out, substance use and abuse, and delinquency (Pettit, 1997). The evidence suggests that intervening early, before behavior problems develop or become entrenched, is most likely

§ The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. * Corresponding author at: 4770 Buford Hwy, Mailstop F-63, Atlanta, GA 30341, USA. Tel.: +1 770 488 1386; fax: +1 770 488 1011. E-mail address: [email protected] (J. Klevens).

0883-0355/$ – see front matter . Published by Elsevier Ltd. doi:10.1016/j.ijer.2010.03.001

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to make a difference in the long run (Durlak & Wells, 1997; Tremblay et al., 1991; Webster-Stratton & Taylor, 2001). Therefore we will briefly review early intervention efforts (i.e., before age 9). Various risk factors for violence such as lack of commitment to school, academic failure, and peer influence occur within the school context (U.S. Department of Health and Human Services, 2001). Schools are also important participants in the socialization of children and provide opportunities for modeling and reinforcing appropriate behaviors. Consequently, intervening in schools is an invaluable opportunity to affect children’s aggression and antisocial behaviors. School-based interventions are particularly attractive preventive strategies because most children spend about half of their waking hours in school and are easily accessible ensuring high levels of program attendance. Although there are school-based interventions that target children who show behavior problems (e.g., August, Lee, Bloomquist, Realmuto, & Hektner, 2003), most interventions in schools are universal, that is, they are delivered to all children regardless of their level of risk (Gottfredson et al., 2000). Recent evidence shows that universal school interventions can reduce rates of violence among school-aged children (Hahn et al., 2007), and are considered to be particularly promising interventions to prevent the problems of juvenile delinquency and youth violence (Reid & Eddy, 1997). Successful universal school-based interventions in elementary school have utilized a variety of strategies. Some have relied on curricula to improve children’s social and emotional functioning, problem-solving and/or conflict resolution skills (e.g., Fitzgerald & Edstrom, 2006; Greenberg & Kusche´, 2006). Others have focused on changing the environment by training teachers in classroom management techniques that reduce opportunities for conflict and promote prosocial behavior (e.g., Kellam, Rebok, Ialongo, & Mayer, 1994), strategies to change school climate (e.g., Embry, Flannery, Vazsonyi, Powell, & Atha, 1996), or instructional techniques to increase engagement (e.g., Shogren, Faggella-Luby, Bae, & Weymeyer, 2004). However, the utility of these school-based interventions is limited for some communities. Many of these successful programs have been implemented in schools in which teachers are well-trained, teaching resources (e.g., textbooks, workbooks, and audiovisual aids) are available, and classroom sizes are limited. Some of these programs are particularly expensive because they require hiring additional trained staff and the purchase of costly materials. Schools in poorer communities which are at higher risk for violence and delinquency often lack these resources and are unable to hire new staff or purchase materials. Less costly interventions in terms of financial and human resources need to be identified and evaluated in resource-poor settings. Others have called for the need to develop and evaluate interventions that match the contexts and needs of schools (Stoiber & Waas, 2002). The first purpose of this pilot study was to respond to this research need: to establish the effectiveness of a low cost universal intervention in a resource-poor setting and new context. The universal intervention selected was improving classroom management. Classroom management is defined as a set of ‘‘actions that teachers take to create an environment that supports and facilitates both academic and social learning’’ (Evertson & Weinstein, 2006, p. 4). Classroom management techniques include arranging the physical environment to reduce opportunities for conflict, establishing and consistently enforcing clear rules, instituting routines and procedures, and maintaining students’ engagement in activities (Brophy, 2006). Classroom management is universal in that it affects all children in the classroom, and it is relatively inexpensive because it does not require hiring additional staff or acquisition of materials. In addition, instead of taking time away from teaching, it can actually increase teaching time available by reducing classroom disruptions. The resource-poor setting and new context selected for this intervention was Pereira, Colombia. Pereira is located in the Andes Mountains about 124 miles northwest of Colombia’s capital, Bogota´. With a population around 450,000 (33% of which live in poverty), its homicide rate is about 76 per 100,000 (Alcaldı´a de Pereira, 2008). This rate is more than double the rate of the most violent cities in the U.S. (U.S. Department of Justice, Federal Bureau of Investigation, n.d.), making Pereira the second most violent city in Colombia. Thirty percent of the homicide victims are youth between the ages of 13 and 25 (Medicina Legal Regional Occidental, 2006). Public schools in Pereira serve the poorest sectors of the population (Gobernacio´n de Risaralda, 2005). Poor children tend to be at highest risk for problem behavior, and therefore teachers in public schools are particularly challenged to maintain classroom order. In addition, teachers in public schools have less training and tend to have fewer resources. On average there is about one teacher per 40 students and teaching materials are limited to chalk and blackboards. Although Pereira is in a less developed country, conditions such as these are similar to many high risk neighborhoods in the U.S. as well as large cities in Latin America, and therefore our findings may have relevance for other similar communities. The second purpose of our study was to compare the relative effectiveness of improved classroom management (‘‘teacher-only intervention’’) to an intervention combining improved classroom management with improved parenting (‘‘teacher/parent combined intervention’’). Families and caregivers are strong influences in determining a child’s risk for aggressive and antisocial behavior (Hawkins et al., 1998; Reese, Vera, Simon, & Ikeda, 2000). Several strategies modifying parenting practices among parents of young children have been successful in preventing or reducing children’s aggressive and antisocial behavior (e.g., Eckenrode et al., 2001; Hutchings et al., 2007; Love et al., 2005; Zubrick et al., 2005). A preliminary evaluation, based on pre-post assessment of a teacher/parent combined intervention in Medellı´n, Colombia suggested that it may contribute to decreases in children’s aggressive and antisocial behaviors (Duque, Orduz, Sandoval, Caicedo, & Klevens, 2007). However, there were multiple problems with this evaluation: no control group, low fidelity to the design, and multiple obstacles to implementing the parent component of the intervention. Thus, questions remained as to the overall effectiveness of the teacher/parent combined intervention and the additive effect of the parent component. Furthermore, experts have recommended intervening across settings to increase impact because children at risk for aggressive and antisocial behavior are usually exposed to multiple risk factors in many settings (Burke et al., 2002; Howard,

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Flora, & Griffin, 1999; Lochman, Salekin, and Haaga, 2003; Tremblay & Craig, 1995; Wasserman & Miller, 1998). Thus, the recent trend in early violence prevention efforts is to combine parenting and school interventions in response to experts’ recommendations (e.g., Barrera et al., 2002; Conduct Problems Prevention Research Group, 2002; Webster-Stratton et al., 2001). Although this makes sense, more comprehensive programs are usually more expensive and are not necessarily more effective (see for example August et al., 2003). Randomized controlled trials provide the strongest evidence of effectiveness of an intervention (American Psychological Association Task Force on Psychological Intervention Guidelines, 1995; Flay et al., 2005). When these trials involve randomization of clusters, analyses need to address the effects of clustering on standard errors to avoid overestimating effect size (Stoolmiller, Eddy, & Reid, 2000). This randomized cluster trial contributes to the discussion on comprehensive vs. single component interventions by comparing the effectiveness of a teacher/parent combined intervention to a teacher-only intervention while adjusting for the effects of clustering. 2. Methods To evaluate the impact of the teacher-only and teacher/parent combined intervention on childhood aggression and prosocial behavior, we conducted a three-arm cluster randomized controlled trial with pre-post assessments of outcomes among first and second grade students in public schools in Pereira, Colombia. Arm one was the teacher/parent combined intervention, arm two was the intervention delivered only to teachers, and arm three was a no intervention control group. 2.1. Participants Twelve public schools (from a total of 102 public elementary schools in Pereira) were selected by the city’s Departments of Education and Health as potentially receptive to participating in the trial (based on previous collaborations) and with the least teacher mobility. The intervention and randomization procedures were described to principals at each school. All 12 schools agreed to participate. The schools were stratified into three groups based on the number of students in the first and second grades. Schools within each stratum were randomly assigned to one of three arms using a computer generated algorithm. As a result, five schools with a total of 40 first and second grade classrooms were assigned to the teacher-only intervention group, four schools with a total of 39 first and second grade classrooms were assigned to the teacher/parent combined intervention group, and 3 schools with a total of 41 first and second grade classrooms were assigned to a wait-list control group. Parents and teachers were invited to a school meeting in which the project and evaluation procedures were described, and after which a consent form describing the project was sent to all parents in grades one and two of the participating schools to obtain permission to collect information on their child. Children in all participating classrooms were informed that some teachers would be participating in a training and that information about each child would be collected to establish the impact of the training but that they could elect to not have this information collected if they did not want. No child asked to be excluded from data collection. About eight percent of parents did not return the consent form or chose not to allow this information to be collected for their child. Non-participation rates were significantly lower in the teacher-only intervention group compared to the teacher/parent combined intervention and control groups (0.9% vs. 14.5% vs. 8.6%; x2 = 120.7; p < .001). An additional seven percent of the children were unavailable at the end of the school year for follow-up. Lost-tofollow-up rates did not differ significantly across groups and children lost-to-follow-up did not differ from children with complete data by age, percent male, or baseline aggression or prosocial behavior scores. In sum, of the total number of first and second grade students available for participation in these 12 schools (n = 2937; teacher–parent combined intervention group = 787; teacher-only intervention group = 881; control group = 823), 84.8% (n = 2491) participated in the study and completed both assessments. 2.2. Interventions 2.2.1. The teachers’ intervention The first intervention evaluated in this trial was a teachers’ training that focused on standard classroom management techniques (i.e., arranging the physical environment to reduce opportunities for conflict, establishing and consistently enforcing clear rules, and instituting routines and procedures) and strategies for shaping children’s behaviors (i.e., modeling and reinforcing appropriate behavior consistently in the classroom’s daily activities and interactions). First and second grade teachers from the participating schools in either the teacher-only or the teacher/parent combined intervention groups were invited to attend 10, 4-h weekly workshops for training (40 h total) at the University of Technology of Pereira. As an incentive, teachers received continuing education credits for attending the training. All the first and second grade teachers in schools assigned to the two intervention groups participated (n = 78) and were divided into two groups for this training. Twelve teachers missed one workshop each. The content of the teachers’ intervention relied heavily on Slaby, Roedell, Arezzo, and Hendrix’s (1995) recommendations for preventing violence in the classroom with young children. Table 1 describes the topic and content of each session. In each training session, teachers were given a short introduction on the topic of the day which was followed by questions to

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Table 1 Content of teacher training sessions. Session

Topics and main points covered

1.

The teacher’s role in violence prevention  Why do violence prevention in the school?  What causes childhood aggression?  How can teachers prevent violence?  How this training and manual is set up  The importance of prosocial skills

2.

Communication  How good communication can prevent the use of aggression  The importance of listening and how to listen  Teaching children to take turns speaking and listening to and respecting others’ opinions

3.

Understanding the other’s perspective  Could it be accidental or was it intentional?  Helping children put themselves in somebody else’s shoes  Finding similarities, differences, and the uniqueness amongst ourselves  Apologizing

4.

Teaching assertiveness skills  Helping children recognize and express their feelings  Breaking the aggressor-victim dynamics by promoting the victim’s assertiveness skills

5.

Promoting cooperation and sharing  The importance of teamwork  Activities that promote working together instead of competition  Downplaying material possessions.

6.

Teachers are role models  Communicating values with our actions  Showing our affection to students

7.

Redesigning the classroom and classroom procedures to reduce conflict  Suggestions for making your classroom look inviting  The importance of planning and preparation for smooth transitions  The importance of routines

8.

Authority in the classroom  Negotiating expectations and rules  Teaching children how to follow instructions  Catching children being good and effective praise

9.

Intervening constructively while minimizing rewards for aggressive behavior  The importance of consistent and contingent intervention  Strategies for empowering the victim  When and how to help the aggressor understand the consequences of aggression, strategies for managing anger, and alternatives to aggression

10.

Appropriate consequences for aggressive behavior  Addressing violence outside the classroom  Helping children understand and express their feelings about violence in their home, their neighborhood, and in the media, its consequences, and safety behaviors  Signs of Post-Traumatic Stress Disorder, child abuse, and where to report/refer

promote critical reflection and discussion on current teaching practices. Most sessions also provided opportunities to roleplay the behaviors covered and concluded with a homework assignment to be completed during the week. Two of the coauthors (JWM and AD) facilitated all the sessions in both training groups by alternating the different sections of the session. Two assistants helped with check-in, distribution of materials, keeping time, and coordinating the coffee break. A teacher’s manual distributed to all teachers provided information on the same 10 topics in more detail (Martı´nez, Duque Franco, Mora Restrepo, Mora Restrepo, & Salazar Herrera, n.d.). Each week, in between teacher training sessions, two of the coauthors (JWM and AD) and 28 last year pedagogy students, previously trained in the teachers’ intervention and in observation and feedback methods, were assigned to observe four teachers for 20 min each in their classrooms using a structured checklist to identify the number of times teachers implemented the recommended behaviors (see Appendix A). This information was used to provide written and verbal feedback to the teachers and was not available to evaluate the implementation of the intervention. Interrater reliability of these ratings was not established. After the training was completed, teachers gave an oral presentation on the strategies used, results observed, and their plans for continuing to implement these strategies in their daily interactions for the 5 remaining months of the school year. No information on the actual implementation was collected after training was completed.

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2.2.2. The teacher/parent combined intervention The second intervention group received the same teachers’ intervention described above combined with a parenting intervention. The parenting intervention covered the same topics as the teachers’ intervention described in Table 1 with the exception of session 7 (redesigning the classroom). Instead, there was a special session on teaching prosocial behaviors (i.e., being a good role model and using praise to encourage courtesy, respect, and cooperation). Parents were invited to schools for 1-h group discussions once a week for 10 weeks. These differed from the teacher training in that parent groups were smaller (10–12 per group) and grouped by the children’s classroom. The same two coauthors (JWM and AD) who facilitated the teachers’ training, also co-facilitated the parents’ groups. Each session began with an introduction to the topic, followed by an informal discussion over breakfast in which experiences and questions were shared. All parents in this intervention group received a manual with more detailed information on the same topics, regardless of their attendance at group discussions. Parents were not observed or tested to establish changes in knowledge or behaviors. Parents did not receive any type of payment other than breakfast for their participation. Teachers in the teacher/parent combined intervention actively promoted parental participation and informed parents that these sessions would provide parents with information on strategies to reduce children’s aggressive behavior. Project staff obtained permission from workplaces for those parents citing work as a barrier to participation. Over half (57.1%) of the parents in the teacher/parent combined intervention arm of the trial attended at least one group session but among those who attended, 90% attended less than three sessions. 2.3. Control schools Teachers and parents in control schools were given the same information about the project as in the intervention schools. After randomization, meetings with teachers in control schools were conducted periodically to reiterate the importance of serving as a control to establish the effectiveness of an intervention. The Department of Education as well as the principals at the control schools agreed to not allow the implementation of any type of intervention in these schools that might have effects on teachers’ or children’s behaviors and compliance with this agreement was checked at each periodic visit. Control schools received the teacher training at the end of the study period. 2.4. Outcome measures Our main outcomes of interest were aggressive/antisocial and prosocial behavior. The aggression and prosocial scales use were based on items from the National Longitudinal Survey of Children & Youth (Statistics Canada, 1997). These scales have been previously tested among children in Colombia showing good internal consistency: Cronbach a equal to .93 and .91, respectively, for aggression and prosocial behavior (Agudelo, Giraldo, Gaviria, Sandoval, Rodrı´guez, et al., 2002). Children’s aggressive/antisocial behavior was reported by teachers using a measure with 18 items that included direct physical aggression (e.g., hits or kicks others, gets into fights), indirect aggression (e.g., makes fun of others, gets peers to exclude other children from activities), and antisocial behaviors (e.g., tells lies, ruins others’ games or activities). Prosocial behavior was assessed with 11 items (e.g., shares, picks up, helps others). Indices of aggressive/antisocial behaviors and prosocial behaviors were created from teachers’ reports of how frequently each child showed each behavior in the preceding month with ratings made on a 3-point response scale (never, sometimes, almost always) at the beginning and end of the school year (8 months apart). Scores on the aggressive/antisocial index ranged from 18 to 54 points and on the prosocial index from 11 to 33 points. Children with a score of 38 or more points on the aggressive/antisocial scale (n = 172) were referred to psychiatrists for further evaluation (as required by the university’s Institutional Review Board) but no treatment was provided by the study. Teachers were trained by one of the coauthors (JWM) during the second month of the school year at each intervention school for 2 h on the use of these scales. After an explanation as to the purpose of the scale, each item was reviewed and clarified by giving examples. To practice coding, various case scenarios were presented and appropriate coding was discussed. Teachers were paid $0.40 for their assessment of each child, totaling approximately $32 per teacher for both the baseline and post-test assessments. No information on the test–retest or inter-rater reliability of these ratings was collected or is available from previous studies. Internal consistency as measured by Cronbach’s alpha, among our sample was .95 and .89, respectively, for aggression and prosocial behavior. Information on age and sex was also reported by teachers to establish comparability between groups and as covariates in the multivariate analyses. A timeline of the data collection points and intervention activities is presented in Fig. 1. 2.5. Analyses Intervention and control groups were compared on baseline characteristics to establish comparability. Bivariate analyses were conducted to explore effects of each covariate on change in aggression and prosocial scores. Subsequent analyses of the intervention effect on aggression and prosocial behaviors were conducted utilizing the general linear mixed modeling approach. Specifically, we used PROC GLM in SAS version 9.1.3 with the RANDOM and REPEATED specifications to account for the nesting of children within teachers and teachers within schools, and changes in pre/post-intervention scores,

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Fig. 1. Timeline of project activities.

respectively. Potential confounders (e.g., school, child’s sex and age, and pre-intervention levels of aggression (for prosocial behavior outcome) or prosocial skills (for aggression outcome)) were also included in our model as covariates. We tested all interactions with sex. Intervention effects on aggression and prosocial behavior were tested separately, with the outcome variables as changes in pre- and post-intervention scores for each behavior. Effect sizes comparing each intervention to the control group were calculated utilizing Cohen’s d (Cohen, 1988). Postaggression/prosocial means were adjusted for baseline scores of aggression/prosocial behaviors and demographic covariates. 3. Results 3.1. Comparison of groups on baseline characteristics The full sample of children averaged 7.2 years old, over half was male and about half was in the first grade (see Table 2). Baseline aggression scores in the full sample averaged about 24 (SD = 7.4) (possible range of 18–54) and baseline prosocial behavior scores averaged about 20 (SD = 4.9) (possible range of 11–33). Chi squares and analyses of variance showed that the distribution by sex, school socioeconomic strata (SES), and aggression and prosocial scores at baseline were significantly different across the intervention groups and control group. There were fewer boys in the combined intervention group than in either of the other two conditions. All schools served neighborhoods in the lowest three (out of six) socioeconomic strata but all of the teacher/parent schools were in the lowest SES (i.e., SES one) while about half of the other two groups were in SES two and three. Pairwise t-tests showed significant differences in baseline aggression and prosocial behavior scores between Table 2 Age, sex, academic grades, and pre- and post-intervention aggression and prosocial scores in full sample and among children in teacher/parent combined intervention, teacher-only intervention, and control group.

Average age (SD) % Male* % SES one % SES two and three Average aggression at baseline (SD)** Average aggression post-intervention (SD)** Average prosociality at baseline (SD)** Average prosociality post-intervention (SD)** * **

p < .05. p < .001.

Full sample (n = 2491)

Combined (n = 787)

Teacher-only (n = 881)

Control (n = 823)

7.2 53.6 64.3 35.7 23.9 24.5 19.9 20.6

7.3 49.7 100.0 0.0 25.0 24.9 20.7 21.2

7.2 55.7 44.6 55.4 24.0 23.7 19.5 20.7

7.2 55.0 51.3 48.7 22.6 25.1 19.6 19.9

(1.0)

(7.4) (7.6) (4.9) (4.9)

(1.0)

(8.0) (7.7) (4.9) (4.5)

(1.0)

(7.5) (6.6) (4.8) (5.2)

(1.0)

(6.6) (8.1) (4.9) (4.9)

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Table 3 Differences in change in aggression and prosocial scores by intervention group adjusted for potential confounders. Covariates

Aggression 1  aggression 2 y

Within subject

Time (none) Group Sex Base Aggression Base Prosocial School Age Sex  Group Sex  Base Aggression Sex  Base Prosocial Sex  School Sex  Age y

Prosocial 1  prosocial 2 y

Between subjects

Within subjecty

Between subjectsy

F

p-Value

F

p-Value

F

p-Value

F

p-Value

1.29 32.32 0.09 n/a 5.41 2.71 1.44 4.91 n/a 0.38 1.02 0.06

.256 <.001 .760 n/a .020 .004 .231 .008 n/a .536 .421 .806

n/a 14.38 17.41 n/a 27.27 10.37 3.56 1.20 n/a 2.71 0.75 0.04

n/a <.001 <.001 n/a <.001 <.001 .060 .301 n/a .100 .663 .846

0.25 15.78 0.26 7.82 n/a 8.07 3.65 0.79 0.44 n/a 1.86 0.98

.620 <.001 .607 .005 n/a <.001 .056 .456 .507 n/a .054 .322

n/a 10.59 8.09 22.13 n/a 13.07 1.44 2.58 0.01 n/a 1.68 2.98

n/a <.001 .005 <.001 n/a <.001 .230 .076 .926 n/a .088 .085

Implicit interaction between the variable time and each of the covariate and interaction term.

the two intervention groups and between the parent/teacher combined intervention and the control group with the teacher/ parent combined group scoring higher on both measures. Both intervention groups scored higher than the control group on baseline aggression while the teacher/parent combined intervention was one point higher than both the teacher-only intervention and the control group on prosocial behavior. Baseline differences, except for school SES (given the empty cells), were accounted for in the multivariate model and in estimating effect sizes. 3.2. Aggressive/antisocial behavior Table 3 presents the results of the multivariate analyses. Interactions (between subjects) between sex and all other covariates were not significant for either outcome. The within-subject column under aggression tells us whether there was individual-level change in aggression over time. Results of the multivariate analyses showed a significant interaction between intervention group and time while controlling for other covariates and interactions, indicating significant differences in the mean change of aggression among children between the three intervention groups (F = 26.17, p < .0001). As shown in Fig. 2, the difference between both intervention groups and the control group was due to an increase in aggression scores among the control group while both intervention groups maintained a constant level of aggression. The effect sizes for aggression scores when comparing the teacher-only intervention and the teacher/parent combined intervention to the control group were .23 and .01, respectively. For the teacher-only intervention students, this effect size would be the equivalent of the control group increasing the frequency of engaging in, on average, one and a half items from the aggression inventory from ‘‘sometimes’’ to ‘‘almost always’’. There were significant group differences in aggression level among children in the three intervention groups, between boys and girls, those with different pre-existing level of prosocial behavior, and students from different schools. Boys and girls differed by group over time as evidenced by the significant interaction between sex  group  time (F = 5.53, p = .004). Fig. 3 shows aggression changing in the same direction for boys and girls in each of the groups with higher levels of aggression for boys at both assessments and a steeper increase in aggression for boys from pre to post-tests among the controls.

Fig. 2. Change over time in aggression and prosocial scores among intervention groups and control.

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Fig. 3. Change over time in aggression scores among intervention groups and control for boys and girls.

3.3. Prosocial behavior The intervention also had a significant effect on prosocial behavior over time (see Table 3). Fig. 2 illustrates this change in prosocial behavior scores in the three groups. Prosocial scores increased in the teacher-only group (comparison of slope to control group: F = 25.15, p < .0001) but remained constant in both the teacher/parent combined intervention group and the control group. The effect sizes for prosocial scores when comparing the teacher-only intervention and the teacher/parent combined intervention to the control group were .22 and .19, respectively. Children in different intervention groups, gender, pre-existing level of aggression, and schools had significantly different levels of change in prosocial scores. Interactions (between subjects) between sex and all other covariates were not significant for either aggression or prosocial behavior. 4. Discussion In this cluster randomized controlled trial to test and compare the impact on aggressive and prosocial behavior of two interventions among first and second grade children we observed a small prevention effect on aggression between both interventions and the control group. However, that difference was due to aggressive behavior remaining constant over time in both intervention groups while increasing in the control group. As for prosocial behavior, the teacher-only intervention had a small positive effect in increasing prosocial behavior while the levels of prosocial behavior in the teacher/parent combined intervention and control groups did not change from pre to post-intervention. Randomized controlled trials, such as this one, provide the strongest evidence of effectiveness of an intervention (American Psychological Association Task Force on Psychological Intervention Guidelines, 1995; Flay et al., 2005). Although randomization reduces the likelihood that participants in the intervention differ from participants in the control group at the outset on variables that may affect the outcomes, participants in this trial differed significantly on all measures. However, pre-intervention differences were controlled for by using multivariate techniques. In addition, our analyses address the problem of clustering which has sometimes been ignored in cluster trials of interventions (Stoolmiller et al., 2000). With traditional analyses, because children are clustered within classrooms and within schools, and individuals within a cluster are more similar than between clusters, standard errors will be underestimated and effect sizes may appear significant when they are not. This trial adjusted for the effects of clustering by using general linear mixed modeling with the random specifications to account for the nesting of children within teachers (as a proxy for classrooms) and teachers within schools. We were also able to obtain good student participation rates and lost relatively few children at follow-up. Although effects were small, because this was an ‘‘intent to treat’’ analysis (Hulley & Cummings, 1988), this trial provides a more realistic assessment of how large effects might be in the ‘‘real world’’ where all teachers and parents may not implement the intervention as well or as often as intended, and all children may not be equally exposed. However, given that the schools selected for this trial had lower teacher mobility and had in the past been more receptive to interventions, our results might have been better than those that might be observed in a typical school. An important limitation of this evaluation is the exclusive reliance on teachers’ reports for outcomes. Due to limited funding, teachers in this study acted as both interventionists and raters of children’s behaviors. Teachers’ reports may have been affected by the characteristics of the intervention itself, that is, they may have perceived positive changes in the children in their classroom even if no change had actually occurred (Stoolmiller et al., 2000). Although this effect should have occurred similarly in both intervention groups, teachers in the teacher/parent combined intervention group may have had greater expectations for behavior change because of parental involvement. Future evaluations should utilize multiple information sources, especially direct blinded observations with independent and trained coders, when logistically possible.

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An additional limitation was the use of a measure that has not been adequately validated in this population. Although the scales appeared internally consistent in our sample as well as in the sample of children it was originally tested in, we do not know its test–retest or inter-rater reliability, sensitivity to change or validity. This is a common problem when conducting research in a less developed country. Funding for research in developing countries is scarce, and the research needed to validate measures developed in other languages or contexts is not usually seen as a priority. Without this preliminary type of research, it is hard to know how well our outcomes were actually measured. A surprising finding is the comparatively weaker effect of the teacher/parent combined intervention on prosocial behavior. However, a recent meta-analysis of school-based interventions to reduce problem behavior showed that multicomponent interventions were not better than single component interventions (Wilson & Lipsey, 2007). Although we hypothesized that involving parents in addition to teachers would increase the impact of intervention, most parents did not actually attend the discussion groups. Poor rates of parental participation in discussion groups are not uncommon (e.g., August et al., 2003; Heinrichs, Bertram, Kuschel, & Hahlweg, 2005). Just over half of the parents attended at least one session but among those who attended, only 17% attended five or more sessions, leaving us basically with two similar interventions. However, given that training of teachers was the same in both intervention groups, effects in the two groups should have been similar. A potential explanation for why we did not observe similar effects in the two intervention groups is the existence of differences between groups that we were not able to control for (e.g., children’s socioeconomic status) because of empty cells. All of the teacher/parent schools were in the lowest SES. The significantly higher rates of parental consent and lower rates of children lost-to-follow-up in the teacher-only intervention suggest that this group of children may have differed on some other uncontrolled for characteristics as well. Another explanation might be differing levels of implementation of the teacher intervention in the two groups. Unfortunately, because data on fidelity of the implementation were not collected, we do not know if this in fact explains the smaller effects in the teacher/parent combined intervention group. Our experience of poor parental attendance coupled with a similar experience when a parenting intervention was tested in Medellı´n suggests that universal parenting groups may not be a useful intervention in community settings such as these. Others have observed that poor parental attendance is associated with parental perceptions of their child having less problem behavior (Barkley et al., 2000; Haggerty et al., 2002) suggesting that perhaps most parents did not feel a need for the intervention. Despite these limitations, the findings from this preliminary evaluation add to the limited literature, especially for resource-poor settings, suggesting that changing teacher responses to student behavior might prevent increases in children’s aggressive and antisocial behaviors in the classroom (Dolan et al., 1993; Gottlieb & Polirstok, 2005; Greenwood, Hops, & Walker, 1977; Greenwood et al., 1979; Mayer & Butterworth, 1979; Mayer, Butterworth, Nafpaktitis, & SulzerAzaroff, 1983; Trovato, Harris, Pryor, & Wilkinson, 1992). Many questions remain as to the utility of this intervention in a setting such as ours. More rigorous trials should be conducted in which groups are comparable, outcome measures are assessed blindly with multiple methods, and participants are followed for longer periods. Future follow-up evaluations of this trial in Pereira will establish whether this 40-h teacher training is enough to motivate teachers to continue implementing the intervention on their own, how well it is implemented, and whether it has any impact on other outcomes such as school performance. Unfortunately, because the control schools received the teacher training once the trial was completed, we will not know if decreases in children’s aggression are sustained over time. Given the special characteristics of the schools where this trial was implemented (lower teacher mobility), and higher SES of the teacher-only intervention schools, the interventions should be replicated in schools with other characteristics before deciding on the effectiveness or ineffectiveness of either of the interventions. Although our findings suggest that 1 year of intervention can improve behaviors, other studies will be needed to determine if providing the intervention over a longer period of time (e.g., throughout elementary school) can increase the impact on children. Though other similar interventions in first and second grade have led to reductions in adolescent problem behavior (e.g., Furr-Holden et al., 2004; Ialongo, Poduska, Werthamer, & Kellam, 2001; Kellam, Ling, Merisca, Brown, & Ialongo, 1998; Storr, Ialongo, Kellam, & Anthony, 2002) and a recently published trial with longer-term follow-up has shown an impact on young adult antisocial disorder, substance use, and use of services for behavioral or psychiatric conditions (Kellam et al., 2008; Poduska et al., 2008; Wilcox et al., 2008), more rigorous studies will be needed to establish the impact of this particular teacher training in elementary school on future adolescent problem behaviors in this new context. The costs for this teachers’ intervention are relatively low: 10, 4-h workshops, 10 coaching sessions, and a manual. The intervention did not take away from teaching time, and may have increased opportunities for teaching as a result of a decrease in disruptive behavior. This relatively low cost intervention deserves further examination to determine its potential impact on aggression, school performance and retention, youth violence, and juvenile delinquency in the long-term. Even with small impacts, low cost interventions that are universal in nature could be very attractive from a public policy perspective. Acknowledgements This study was supported by Grant no. 457 from the Colombian Institute for the Development of Science and Technology (Colciencias), and funds from Universidad Tecnolo´gica de Pereira and the Fundacio´n Universitaria del Area Andina de Pereira. We would like to thank the students from the Fundacio´n Universitaria del Area Andina for their research assistance, the

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Universidad de Antioquia for their technical assistance, and school staff, parents, and children for their participation and support.

Appendix A. Teacher observation checklist Date: ____________________________________________ Teacher’s name: ___________________________________ School: ______________________ Grade: _____________

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References Agudelo, L. M., Giraldo, C. A., Gaviria, M. B., Sandoval, C. A., Rodrı´guez, M. A., Gomez, J. F., et al. (2002). Caracterı´sticas de las familias y escuelas relacionadas con los comportamientos agresivos y prosociales en nin˜os y nin˜as de 3 a 11 an˜os. Characteristics of families and schools associated with aggressive and prosocial behaviors in children from 3 to 11 years old]. Medellı´n: Colciencias, CES, Universidad de Antioquia. Alcaldı´a de Pereira. (2008). Plan de Desarrollo. Pereira: Regio´n de Oportunidades 2008 2011. Development plan. Pereira, region of opportunities 2008–2011]. Pereira: Author. American Psychological Association Task Force Task Force on Promotion and Dissemination of Psychological Procedures. (1995). Training in and dissemination of empirically-validated psychological treatments. The Clinical Psychologist, 48(1), 3–23. August, G. J., Lee, S. S., Bloomquist, M. L., Realmuto, G. M., & Hektner, J. M. (2003). Dissemination of an evidence-based prevention innovation for aggressive children living in culturally diverse, urban neighborhoods: The Early Risers effectiveness study. Prevention Science, 4, 271–286. Barkley, R. A., Shelton, T. L., Crosswait, C., Moorehouse, M., Fletcher, K., Barrett, S., et al. (2000). Multi-method psychoeducational intervention for preschool children with disruptive behavior: Preliminary results at post-treatment. Journal of Child Psychology and Psychiatry & Allied Disciplines, 41, 319– 332. Barrera, M., Biglan, A., Taylor, T. K., Gunn, B. K., Smolkowski, K., Black, C., et al. (2002). Early elementary school intervention to reduce conduct problems: A randomized trial with Hispanic and non-Hispanic children. Prevention Science, 3, 83–94. Broidy, L. M., Nagin, D. S., Tremblay, R. E., Bates, J. E., Brame, B., Dodge, K. A., et al. (2003). Developmental trajectories of childhood disruptive behaviors and adolescent delinquency: A six-site, cross-national study. Developmental Psychology, 39, 222–245. Brophy, J. (2006). History of research on classroom management. In C. M. Evertson & C. S. Weinstein (Eds.), Handbook of classroom management. Research, practice, and contemporary issues (pp. 17–43). Mahwah, NJ: Lawrence Erlbaum. Burke, J. D., Loeber, R., & Birmaher, B. (2002). Oppositional defiant disorder and conduct disorder: A review of the past 10 years. Part II. Journal of the American Academy of Child & Adolescent Psychiatry, 41, 1275–1293. Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale, NJ: Lawrence Earlbaum Associates. Conduct Problems Prevention Research Group. (2002). The implementation of the Fast Track Program: An example of a large-scale prevention science efficacy trial. Journal of Abnormal Child Psychology, 30, 1–17.

318

J. Klevens et al. / International Journal of Educational Research 48 (2009) 307–319

Dolan, L. J., Kellam, S. G., Brown, C. H., Werthamer-Larson, L., Rebok, G. W., Mayer, L. S., et al. (1993). The short-term impact of two classroom-based preventive interventions on aggressive and shy behaviors and poor achievement. Journal of Applied Developmental Psychology, 14, 317–345. Duque, L. F., Orduz, J. F., Sandoval, J. J., Caicedo, B. E., & Klevens, J. (2007). Lecciones del programa de prevencio´n temprana de violencia, Medellı´n, Colombia [Lessons from the early violence prevention program in Medellı´n, Colombia]. PanAmerican Journal of Public Health, 21, 21–29. Durlak, J. A., & Wells, A. M. (1997). Primary prevention mental health programs for children and adolescents: A meta-analytic review. American Journal of Community Psychology, 25, 115–152. Eckenrode, J., Sielinski, D., Smith, E., Marcynyszyn, L. A., Henderson, C. R., Kitzman, H., et al. (2001). Child maltreatment and the early onset of problem behaviors: Can a program of nurse home visitation break the link? Development & Psychopathology, 13, 873–890. Embry, D. D., Flannery, D. J., Vazsonyi, A. T., Powell, K. E., & Atha, H. (1996). Peacebuilders: A theoretically driven, school-based model for early violence prevention. American Journal of Preventive Medicine, 12(Suppl.), 91–100. Evertson, C. M., & Weinstein, C. S. (Eds.). (2006). Handbook of classroom management. Research, Practice, and Contemporary Issues. Mahwah, NJ: Lawrence Erlbaum. Farrington, D. P. (2005). Childhood origins of antisocial behavior. Clinical Psychology & Psychotherapy, 12, 177–190. Farrington, D. P., & Loeber, R. (2000). Epidemiology of juvenile violence. Child and Adolescent Psychiatric Clinics of North America, 9, 733–748. Fitzgerald, P. D., & Edstrom, L. V. (2006). Second step: A violence prevention curriculum. In S. R. Jimerson & M. J. Furlong (Eds.), The handbook of school violence and safety (pp. 383–394). Mahwah, NJ: Lawrence Erlbaum. Flay, B. R., Biglan, A., Boruch, R. F., Gonzalez-Castro, F., Gottfredsen, D., Kellam, S. G., et al. (2005). Standards of evidence: Criteria for efficacy, effectiveness and dissemination. Prevention Science, 6, 151–175. Furr-Holden, C. D., Ialongo, N. S., Anthony, J. C., Petras, H., & Kellam, S. G. (2004). Developmentally inspired drug prevention: Middle school outcomes in a schoolbased randomized prevention trial. Drug and Alcohol Dependence, 73, 149–158. Gobernacio´n de Risaralda. (2005). Estadı´sticas de Educacio´n (Statistics in education). Oficina de Planeacio´n. Secretaria Departamental de Educacio´n. Retrieved September 16, 2005 from www.risaralda.gov.co. Gottfredson, G. D., Gottfredson, D. C., Czeh, E. R., Cantor, D., Crosse, S. B., & Hantman, I. (2000). National study of delinquency prevention in schools. Retrieved August 20, 2008, from http://www.gottfredson.com/Delinquency%20Prevention%20in%20Schools/summary.pdf. Gottlieb, J., & Polirstok, S. (2005). Program to reduce behavioral infractions and referrals to special education. Children & Schools, 27, 53–57. Greenberg, M. T., & Kusche´, C. A. (2006). Building social and emotional competence: The PATHS curriculum. In S. R. Jimerson & M. J. Furlong (Eds.), The handbook of school violence and safety (pp. 395–412). Mahwah, NJ: Lawrence Erlbaum. Greenwood, C. R., Hops, H., & Walker, H. M. (1977). The program for academic survival skills (PASS): Effects on student behavior and achievement. Journal of School Psychology, 15, 25–35. Greenwood, C. R., Hops, H., Walker, H. M., Guild, J. J., Stokes, J., Young, K. R., et al. (1979). Standardized classroom management programs: Social validation and replication studies in Utah and Oregon. Journal of Applied Behavior Analysis, 12, 25–253. Haggerty, K. P., Fleming, C. B., Lonczak, H. S., Oxford, M. L., Harachi, T. W., & Catalano, R. F. (2002). Predictors of participation in parenting workshops. Journal of Primary Prevention, 22, 375–387. Hahn, R., Fuqua-Whitley, D., Wethington, H., Lowy, J., Crosby, A., Fullilove, M., et al. (2007). Effectiveness of universal school-based programs to prevent violent and aggressive behavior: A systematic review. American Journal of Preventive Medicine, 33(Suppl.), S114–S129. Hawkins, J. D., Herrenkohl, T., Farrington, D. P., Brewer, D., Catalano, R. F., & Harachi, T. W. (1998). A review of predictors of youth violence. In R. Loeber & D. P. Farrington (Eds.), Serious and violent juvenile offenders (pp. 106–146). Thousand Oaks, CA: Sage. Heinrichs, N., Bertram, H., Kuschel, A., & Hahlweg, K. (2005). Parent recruitment and retention in a universal prevention program for child behavior and emotional problems: Barriers to research and program participation. Prevention Science, 6, 275–286. Howard, K. A., Flora, J., & Griffin, M. (1999). Violence prevention programs in schools: State of the science and implications for future research. Applied and Preventive Psychology, 8, 197–215. Huesmann, L. R., Eron, L. D., & Dubow, E. F. (2002). Childhood predictors of adult criminality: Are all risk factors reflected in childhood aggressiveness? Criminal Behaviour and Mental Health, 12, 185–208. Hulley, S. B., & Cummings, S. R. (1988). Designing clinical research (pp. 212–213). Baltimore, MD: Williams & Wilkins. Hutchings, J., Gardner, F., Bywater, T., Daley, D., Whitaker, C., Jones, K., et al. (2007). Parenting intervention in Sure Start services for children at risk of developing conduct disorder: Pragmatic randomized controlled trial. British Medical Journal, 334, 678–685. Ialongo, N., Poduska, J., Werthamer, L., & Kellam, S. G. (2001). The distal impact of two first-grade preventive interventions on conduct problems and disorder in early adolescence. Journal of Emotional and Behavioral Disorders, 9, 146–160. Kellam, S. G., Brown, C. R., Poduska, M., Ialongo, N. S., Wang, W., Toyinbo, P., et al. (2008). Effects of a universal classroom behavior management program in first and second grades on young adult behavioral, psychiatric, and social outcomes. Drug and Alcohol Dependence, 95S, S5–S28. Kellam, S. G., Ling, X., Merisca, R., Brown, C. H., & Ialongo, N. (1998). The effect of the level of aggression in the first grade classroom on the course and malleability of aggressive behavior into middle school. Development and Psychopathology, 10, 165–185. Kellam, S. G., Rebok, G. W., Ialongo, N., & Mayer, L. S. (1994). The course and malleability of aggressive behavior from early first grade into middle school: Results of a developmental epidemiologically-based preventive trial. Journal of Child Psychology and Psychiatry, 35, 259–281. Lochman, J. E., Salekin, R. T., & Haaga, D. A. (2003). Prevention and intervention with aggressive and disruptive children: Next steps in behavioral intervention. Behavior Therapy, 34, 413–419. Love, J. M., Kisker, E. E., Ross, C., Raikes, H., Constantine, J., Boller, K., et al. (2005). The effectiveness of Early Head Start for 3-year-old children and their parents: Lessons for policy and programs. Developmental Psychology, 41, 885–901. Martı´nez, J. W., Duque Franco, A., Mora Restrepo, J., Mora Restrepo, V. X., Salazar Herrera, L. M. (n.d.). Alternativas para la reduccio´n del comportamiento agresivo de los nin˜os escolarizados (Alternatives for the reduction of aggressive behavior in school children). Pereira: Homeris. Retrieved July 11, 2008 from: www.utp.edu.co/ jose01william. Mayer, G. R., & Butterworth, T. W. (1979). A preventive approach to school violence and vandalism: An experimental study. The Personnel and Guidance Journal, 57, 436–441. Mayer, G. R., Butterworth, T. W., Nafpaktitis, M., & Sulzer-Azaroff, B. (1983). Preventing school vandalism and improving discipline: A three-year study. Journal of Applied Behavior Analysis, 16, 355–369. Medicina Legal Regional Occidental. (2006). Violencia y accidentalidad. Violence and accidents]. Pereira: Author. Mercy, J. A., & O’Carroll, P. W. (1988). New direction in violence prediction: The public health arena. Violence and Victims, 3, 285–301. Pettit, G. S. (1997). The developmental course of violence and aggression. Psychiatric Clinics of North America, 20, 283–299. Poduska, J., Kellam, S. G., Wang, W., Brown, C. H., Ialongo, N., & Toyinbo, P. (2008). Impact of the Good Behavior Game, a universal classroom-based behavior intervention, on young adult service use for problems with emotions, behavior, or drugs or alcohol. Drug and Alcohol Dependence, 95, S24–S44. Reese, L. E., Vera, E. M., Simon, T. R., & Ikeda, R. M. (2000). The role of families and care givers as risk and protective factors in preventing youth violence. Clinical Psychology and Family Psychology Review, 3, 61–77. Reid, J. B., & Eddy, J. M. (1997). The prevention of antisocial behavior: Some considerations in the search for effective interventions. In D. M. Stoff, J. Breiling, & J. D. Braser (Eds.), Handbook of antisocial behavior (pp. 343–356). New York: Wiley. Shogren, K. A., Faggella-Luby, M. N., Bae, S. J., & Weymeyer, M. L. (2004). The effect of choice-making as an intervention for problem behavior. Journal of Positive Behavior Interventions, 6, 49–65. Slaby, R. G., Roedell, W. C., Arezzo, D., & Hendrix, K. (1995). Early violence prevention: Tools for teachers of young children. Washington, DC: National Association for the Education of young Children. Statistics Canada. (1997). National Longitudinal Survey of Children and Youth, Overview of survey instruments for 1996–1997 data collection, Cycle 2. Retrieved from www.statcan.gc.ca/dli-ild/meta/nlscy-elnej/cycle2/nlscy-elnej-cycle2-eng.pdf on March 15, 2010.

J. Klevens et al. / International Journal of Educational Research 48 (2009) 307–319

319

Stoiber, K. C., & Waas, G. A. (2002). A contextual and methodological perspective on the evidence-based movement within school psychology in the United States. Educational and Child Psychology, 19, 7–21. Stoolmiller, M., Eddy, J. M., & Reid, J. (2000). Detecting and describing preventive intervention effects in universal school-based randomized trial targeting delinquent and violent behavior. Journal of Consulting and Clinical Psychology, 68, 296–306. Storr, C. L., Ialongo, N. S., Kellam, S. G., & Anthony, J. C. (2002). A randomized controlled trial of two primary intervention strategies to prevent early onset tobacco smoking. Drug and Alcohol Dependence, 66, 51–60. Tremblay, R. E., & Craig, W. (1995). Developmental crime prevention. In M. Tonry & D. P. Farrington (Eds.), Crime and justice, Vol. 19: Building a safer society. Strategic approaches to crime prevention (pp. 151–236). Chicago: University of Chicago Press. Tremblay, R. E., McCord, J., Boileau, H., Charlesbois, P., Gagnon, C., LeBlanc, M., et al. (1991). Can disruptive boys be helped to become competent. Psychiatry, 54, 148–161. Trovato, J., Harris, J., Pryor, C. W., & Wilkinson, S. C. (1992). Teachers in regular classrooms: An applied setting for successful behavior programming. Psychology in the Schools, 29, 52–61. U.S. Department of Health and Human Services. (2001). Youth violence: A report of the surgeon general. Rockville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Injury Prevention and Control; Substance Abuse and Mental Health Services Administration, Center for Mental Health Services; and National Institutes of Health, National Institute of Mental Health. U.S. Department of Justice, Federal Bureau of Investigation. (n.d.). Crime in the United States 2005. Retrieved March 30, 2007 from http://www.fbi.gov/ucr/05cius/ index.html. Wasserman, G. A., & Miller, L. S. (1998). The prevention of serious and violent juvenile offending. In R. Loeber & D. P. Farrington (Eds.), Serious & violent juvenile offenders. Risk factors and successful interventions (pp. 197–247). Thousand Oaks, CA: Sage. Webster-Stratton, C., Reid, M. J., & Hammond, M. (2001). Preventing conduct problems, promoting social competence: A parent and teacher training partnership in Head Start. Journal of Clinical Child Psychology, 30, 283–302. Webster-Stratton, C., & Taylor, T. (2001). Nipping early risk factors in the bud: Preventing substance abuse, delinquency, and violence in adolescence through interventions targeted at young children. Prevention Science, 2, 165–192. Wilcox, H. C., Kellam, S. G., Brown, C. H., Poduska, J., Ialongo, N., Wang, W., et al. (2008). The impact of two universal randomized first- and second-grade classroom interventions on young adult suicide ideation and attempts. Drug and Alcohol Dependence, 95, S60–S73. Wilson, S. J., & Lipsey, M. W. (2007). School-based interventions for aggressive and disruptive behavior: Update of a meta-analysis. American Journal of Preventive Medicine, 33, S130–S143. Zubrick, S. R., Ward, K. A., Silburn, S. R., Lawrence, D., Williams, A. A., Blair, E., et al. (2005). Prevention of child behavior problems through universal implementation of a group behavioral family intervention. Prevention Science, 6, 287–304.