Reid, M. J., Webster-Stratton, C., & Beauchaine, T. P. (2001). Parent training in Head Start: A comparison of program response among African American, Asian American, Caucasian, and Hispanic mothers. Prevention Science, 2(4), 209-227.

Type of Study: Randomized controlled trial
Number of Participants: 634 families provided pre and posttest data. 474 families provided data for the 1-year follow-up.

Population:

• Age — Children: Mean=55.96 months (approximately 4.66 years)
• Race/Ethnicity — Children: 19% African American, 12% Asian American, and 11% Hispanic
• Gender — Children: 54% Male and 46% Female
• Status — Participants were families with children attending Head Start.

Location/Institution: Puget Sound

Summary: (To include basic study design, measures, results, and notable limitations)
Randomly assigned to The Incredible Years program group or the control group. Measures were taken at baseline, post-treatment, and 1 year later. Parenting competency and involvement were measured by the Parenting Practices Interview (PPI), Parent Teacher Involvement Questionnaire (parent and teacher version), home observations with the Dyadic Parent Child Interaction Coding System-Revised (DPCICS-R), and the Coder Impression Inventory (CII). Child competencies were measured by the Child Behavior Checklist, Eyberg Child Behavior Inventory (ECBI), Social Competence Scale (parent), and home observation with the DPCICS-R. Mothers were also assessed with the Brief Anger Aggression Questionnaire, the CESD depression scale, and the Assessing Environments III, which provides information on childhood experiences of abusive punishment. Following treatment, mothers were observed to be more positive, less critical, more consistent, and more competent than were control mothers. Differences across ethnic groups did not exceed chance levels.

Length of controlled postintervention follow-up: 1 year.

Baydar, N., Reid, M. J., & Webster-Stratton, C. (2003). The role of mental health factors and program engagement in the effectiveness of a preventive parenting program for Head Start mothers. Child Development, 74(5), 1433-1453.

Type of Study: Randomized controlled trial
Number of Participants: Control group: 275, Intervention group: 607

Population:

• Age — Mean=56 months (approximately 4.67 years)
• Race/Ethnicity — Control: 56% Caucasian, 19.2% African American, 13% Hispanic, and 7% Asian/Pacific Islander; Intervention: 60.8% Caucasian, 13.7% African American, 9% Hispanic, and 11% Asian/Pacific Islander
• Gender — Children: 53.25% Male
• Status — Participants were families enrolled in Head Start centers.

Location/Institution: Puget Sound

Summary: (To include basic study design, measures, results, and notable limitations)
Participants were randomly assigned to one of two groups: A group that received The Incredible Years training or to a control group that did not receive the training. Mothers with mental health risk factors (depression, anger, history of abuse as a child, and substance abuse) exhibited poorer parenting skills than those without risk factors, as measured by the Parenting Practices Interview, Dyadic Parent-Child Interactive Coding System, and Coder Impression Inventory. However, mothers with risk factors engaged with and benefited from the parenting training program at a level comparable to mothers without these risk factors. Program engagement was assessed by number of sessions attended, percentage of homework assignments completed, and the group leader's rating of engagement. Intervention mothers had lower scores on both harsh/negative parenting and ineffective parenting and higher scores on supportive parenting.

Length of controlled postintervention follow-up: None.

Reid, M. J., Webster-Stratton, C., & Hammond, N. (2003). Follow-up of children who received the Incredible Years intervention for oppositional-defiant disorder: Maintenance and prediction of two-year outcome. Behavior Therapy, 34, 471–491.

Type of Study: Randomized controlled trial
Number of Participants: 159

Population:

• Age — 4-7 years
• Race/Ethnicity — 79% Caucasian
• Gender — 90% Male
• Status — Participants were parents requesting services at the University of Washington Parenting Clinic; either self-referred or referred by physician or teacher.

Location/Institution: University of Washington Parenting Clinic

Summary: (To include basic study design, measures, results, and notable limitations)
This paper presents 2-year follow-up data for a sample of children with oppositional-defiant disorder who were randomly assigned to one of five treatment plans: parent training (PT), parent plus teacher training (PT + TT), child training (CT), child plus teacher training (CT + TT), and parent plus child plus teacher training (PT + CT + TT). Multiple measures were used, including the Eyberg Child Behavior Inventory (ECBI), the Child Behavior Checklist 1.5-5 (CBCL), the Multi-Option Observation System for Experimental Studies (MOOSES) classroom observation coding system, and the Teacher Assessment of School Behavior (TASB). At the 2-year follow-up, approximately 75% of children were functioning in the normal range according to parent and teacher reports. Twenty-five percent of children were classified as treatment nonresponders at home and/or at school. Teacher training added significantly to long-term school outcomes for children who had pervasive behavior problems. Baseline, post, and 1-year follow-up parenting practices distinguished between home treatment responders and nonresponders (parents of nonresponders were more critical and less positive). For children with baseline pervasive home-school problems, baseline maternal parenting and posttreatment marital discord were associated with poor treatment response at home at the 2-year follow-up. In addition, 80% of pervasive children whose mothers were highly critical immediately posttreatment were classified as school nonresponders at the 2-year follow-up.

Length of controlled postintervention follow-up: 2 years.

Reid, M. J., Webster-Stratton, C., & Baydar, N. (2004). Halting the development of conduct problems in Head Start children: The effect of parent training. Journal of Clinical Child and Adolescent Psychology, 33(2), 279-291.

Type of Study: Randomized controlled trial
Number of Participants: 882 children

Population:

• Age — 5 years or younger
• Race/Ethnicity — 51% White, 19% African American, 10% Hispanic, 8% Asian, and 12% mixed or other
• Gender — 53% Male
• Status — Participants were enrolled in Head Start center.

Location/Institution: Puget Sound

Summary: (To include basic study design, measures, results, and notable limitations)
The study uses the same sample as the Baydar, Reid, & Webster-Stratton (2003) study. Participant families were randomly assigned to an intervention group where parents received The Incredible Years parenting program or to a group where the parent received the standard Head Start curriculum. Teachers in the intervention groups also received training on the program content. Data on children's behavior was obtained through both parent and teacher reports and through independent home observation. Pre and post intervention, children were measured on the Eyberg Child Behavior Inventory (ECBI), an inventory of conduct problems. Data was also obtained from the Dyadic Parent-Child Interactive Coding System which allows recording of behaviors of children with conduct problems and their parents, and the Coder Impression Inventory, which describes parenting style, child affect, and behavior. Mothers and children who had parenting or behavior problems at baseline were also identified. Analyses showed that families with problems at baseline benefited most from the program. Changes in conduct problems were also related to maternal engagement in the program and to mothers' success in implementing the positive parenting strategies taught in the program.

Length of controlled postintervention follow-up: None.

Kim, E., Cain, K. C., & Webster-Stratton, C. (2008). The preliminary effect of a parenting program for Korean American mothers: A randomized controlled experimental study. International Journal of Nursing Studies, 45, 1261-1273.

Type of Study: Randomized controlled trial
Number of Participants: 29

Population:

• Age — Children:3-8, Adults: Not specified
• Race/Ethnicity — Adults: 100% Females
• Gender — Adults: 100% Korean
• Status — Participants were first-generation Korean American mothers of young children (3-8 years old).

Location/Institution: Not Specified

Summary: (To include basic study design, measures, results, and notable limitations)
The purpose of this study was to pilot-test the effect of the Incredible Years (IY) parenting program among Korean American mothers. First-generation Korean American mothers of young children were randomly assigned to the IY intervention or to a control group. Mothers reported on discipline styles (positive, appropriate, and harsh), level of acculturation, and their child's outcomes (behavioral problems and social competence) at pre-, post-, and 1-year follow-up intervals. Measures included the Parent Practices Interview, Eyberg Child Behavior Inventory, Social Competence Scale, and a modified version of the Acculturation Rating Scale for Mexican Americans-II (ARSMA-II). After completing the program, intervention group mothers significantly increased use of positive discipline as compared to control group mothers. Among intervention group mothers, high acculturated mothers significantly increased appropriate discipline whereas low-acculturated mothers significantly decreased harsh discipline. In the 1-year follow-up, intervention group mothers maintained the significant effect for positive discipline. Limitations include the small sample size and the larger number of drop-outs in the control group.

Length of controlled postintervention follow-up: 12 months.

Bywater, T., Hutchings, J., Daley, D., Whitaker, C., Yeo, S. T., Jones, K.,...Edwards, R. T. (2009). Long-term effectiveness of a parenting intervention in Sure Start services in Wales for children at risk of developing conduct disorder. British Journal of Psychiatry, 195, 318-324.

Type of Study: Randomized controlled trial
Number of Participants: 104

Population:

• Age — Children: 36-59 months
• Race/Ethnicity — Not Specified
• Gender — Not Specified
• Status — Participants were parents with children aged 36–59 months at risk of developing conduct disorder.

Location/Institution: 11 communities in North and mid Wales, United Kingdom

Summary: (To include basic study design, measures, results, and notable limitations)
This study examined whether the short-term positive effects of a parenting program (The Incredible Years [IY]) were sustained longer term. Parents were randomly assigned to IY (or a wait list control group) and received intervention between baseline and first follow-up. The second and third follow-up (n = 82 and n = 79, respectively) occurred 12 and 18 months after baseline. Measures included the Eyberg Child Behavior Inventory (ECBI), Strengths and Difficulties Questionnaire (SDQ), Conners Abbreviated Parent Rating Scale (CAPRS), Kendall Self-Control Rating Scale (SCRS), Parenting Stress Index–Short Form (PSI–SF), and Beck Depression Inventory (BDI). The significant parent-reported improvements in primary measures of child behavior, parent behavior, parental stress, and depression gained at follow-up one were maintained to follow-up three, as were improved observed child and parent behaviors. Overall, 63% of children made a minimum significant change on the ECBI Problem Scale between baseline and follow-up (using intention-to-treat data), 54% made a large change, and 39% made a very large change. Child contact with health and social services had reduced at follow-up three. Limitations included the lack of a control group comparison at the 12 and 18 month follow-ups.

Length of controlled postintervention follow-up: Approximately 9 and 15 months.

Drugli, M. B., Larsson, B., Fossum, S., & Mørch, W. (2010). Five- to six-year outcome and its prediction for children with ODD/CD treated with parent training. Journal of Child Psychology and Psychiatry, 51(5), 559–566.

Type of Study: Randomized controlled trial
Number of Participants: 54

Population:

• Age — Mean=12.1 years follow-up (SD = 1.3)
• Race/Ethnicity — Not specified—All but one family in the study were native Norwegians
• Gender — 83% Male
• Status — Participants were children aged 4–8 referred for treatment because of oppositional or conduct problems reported by their parents.

Location/Institution: Two university cities in Norway

Summary: (To include basic study design, measures, results, and notable limitations)
In the present study, diagnostic status as outcome and predictors of treatment response were examined in a 5 to 6-year follow-up. Out of 99 children who had been treated in a randomized controlled trial evaluating the effects of The Incredible Years parent training or combined parent training and child treatment program, 54.5% participated in the 5 to 6-year follow-up study. Their diagnostic status was determined with the Kiddie-SADS interview. While all children qualified for a diagnosis of Oppositional Defiant Disorder (ODD)/Conduct Disorder (CD) before treatment, 5-6 years later, two-thirds no longer received such a diagnosis, the same proportion as found at the 1-year follow-up. The most powerful pretreatment predictors of diagnostic status at the 5-6-year follow-up were living with mother only and female gender. At post-treatment, the most powerful predictor was found to be high levels of child externalizing problems. The findings of the study support the maintenance of positive long-term results for young children treated with parent training because of serious conduct problems, and identify characteristics of children and families in need of added support to parent training programs. Limitations include the 54.5% participation rate, the reliance on a formal psychiatric diagnosis of ODD/CD in the child as the outcome measure, and the lack of follow-up with the untreated control group sample.

Length of controlled postintervention follow-up: 5-6 years.

Gardner, F., Hutchings, J., Bywater, T., & Whitaker, C. (2010). Who benefits and how does It work? Moderators and mediators of outcome in an effectiveness Trial of a Parenting Intervention. Journal of Clinical Child & Adolescent Psychology. 39(4), 568-580.

Type of Study: Randomized controlled trial
Number of Participants: 133

Population:

• Age — 36-59 months (3-4.9 years)
• Race/Ethnicity — Not Specified
• Gender — 60% Male
• Status — Participants were children in the targeted neighborhoods who scored above the clinical cutoff on the Eyberg Child Behavior Inventory (ECBI) problem or intensity scale.

Location/Institution: 11 socially disadvantaged neighborhoods in the United Kingdom, in receipt of Government funding as Sure Start areas, identified on the basis of high levels of poverty

Summary: (To include basic study design, measures, results, and notable limitations)
This study examined mediators and moderators of change in conduct problems, in a multi-agency randomized trial of The Incredible Years parenting program. Preschoolers at risk for conduct problems (n=153) were randomly assigned to intervention (n=104) and wait-list (n=49) groups. Boys and younger children, and those with more depressed mothers, tended to show greater improvement in conduct problems post-intervention. Other risk factors (i.e., teen or single parenthood, very low income, high initial levels of problem behavior) showed no predictive effects, implying intervention was at least as successful at helping the most disadvantaged families, compared to more advantaged. Mediator analyses found change in positive parenting skill predicted change in conduct problems. Limitations include the small sample size to conduct moderator and mediator analyses.

Length of controlled postintervention follow-up: 3 months.

Webster-Stratton, C., Rinaldi, J., & Reid, J. M. (2011). Long-term outcomes of Incredible Years parenting program: Predictors of adolescent adjustment. Child and Adolescent Mental Health, 16(1), 38-46.

Type of Study: One group pre-test post-test study
Number of Participants: 68

Population:

• Age — 3-8 years at intake; 12-19 years (mean=15 years) at follow-up
• Race/Ethnicity — Not Specified
• Gender — 73% Male
• Status — Participants were self-referred or professionally referred parents of children with child misconduct problems lasting at least six months.

Location/Institution: Not Specified

Summary: (To include basic study design, measures, results, and notable limitations)
Children with early onset conduct problems whose parents received The Incredible Years parent treatment program when they were 3-8 years were contacted and reassessed regarding their social and emotional adjustment 8-12 years later. Assessments included home interviews with parents and teenagers separately; measures included the Child Behavior Checklist 6-18 (CBCL), the Elliott Delinquency Scale, the Revised Children's Manifest Anxiety Scale, and the Child Depression Inventory. At long-term follow-up, 16% and 12% of the teens were in the clinical range according to mother and father reports respectively on the CBCL externalizing scale, compared to 25% and 10%, immediately posttreatment. Thus, parent reports of externalizing problems were stable or slightly improved over the follow-up period. Adolescent reports indicated that 10% were in the clinical range on internalizing behaviors, 23% had engaged in major delinquent acts, and 46% reported some substance use. Eighteen percent of children had criminal justice system involvement and 42% had elevated levels of externalizing behaviors (mother report). Immediate post-treatment factors predicting negative outcomes (delinquent acts) were maternal reports of behavior problems and observed mother–child coercion, indicating that in families where levels of parent-child coercion are still high post-treatment, further intervention may be warranted to prevent future problems. Limitations include the lack of a control group, the broad age range of youth at the long-term follow-up time point, and a lack of information on interventions received between treatment and the long-term follow-up time point.

Length of controlled postintervention follow-up: 8-12 years.

Bywater, T., Hutchings, J., Linck, P., Whitaker, C., Daley, D., Yeo, S. T., & Edwards, R. T. (2011). Incredible Years parent training support for foster carers in Wales: A multi-centre feasibility study. Child: Care, Health and Development, 37(2), 233–243.

Type of Study: Randomized controlled trial
Number of Participants: 46

Population:

• Age — Adults: 28-66 years; Children: 2-16 years
• Race/Ethnicity — Not specified
• Gender — Children: 24 Males and 22 Females
• Status — Participants were foster carers in three local authorities in North and Mid Wales.

Location/Institution: North and Mid Wales, United Kingdom

Summary: (To include basic study design, measures, results, and notable limitations)
This study examined the feasibility of delivery and the effectiveness of The Incredible Years (IY) parenting program in supporting foster carers in managing difficult behavior in children in foster care. Foster carers were randomly assigned to the IY intervention or the control group. Measures included the Parenting Scale, Beck Depression Inventory (BDI), Eyberg Child Behavior Inventory (ECBI), and Strengths and Difficulties Questionnaire (SDQ). Analyses showed a significant reduction in child problem behavior and improvement in foster carers' depression levels for intervention families at follow-up, compared with control.

Length of controlled postintervention follow-up: Approximately 12 weeks.