Incredible Years

Evidence Rating  
Evidence rating: Scientifically Supported

Strategies with this rating are most likely to make a difference. These strategies have been tested in many robust studies with consistently positive results.

Health Factors  
Decision Makers
Date last updated

Incredible Years offers parent, teacher, and child training, teaching parents how to parent more effectively and warmly, teachers how to manage classrooms more effectively, and children how to better manage their interpersonal relationships. The program focuses on children up to 12 years old that exhibit or are at risk for behavioral problems1.

What could this strategy improve?

Expected Benefits

Our evidence rating is based on the likelihood of achieving these outcomes:

  • Improved child behavior

  • Improved parenting

  • Improved classroom management

Potential Benefits

Our evidence rating is not based on these outcomes, but these benefits may also be possible:

  • Improved social emotional skills

  • Increased school engagement

What does the research say about effectiveness?

There is strong evidence that Incredible Years (IY) reduces children’s behavioral problems2, 3, 4. The program also improves parenting skills4, 5 and teacher’s classroom management abilities21, 6.

IY reduces children’s behavior problems at home and at school17. The program also reduces children’s aggressive behavior and improves conflict management and social skills. Participation increases children’s cooperation and positive interactions with teachers, parents, and peers1.

Children with more severe behavior issues prior to program participation have the greatest improvements in behavior over the course of IY2, 3. Parent interventions such as IY are effective for preschoolers with Attention Deficit Hyperactivity Disorder8. IY appears especially effective for children with conduct disorder9 and Oppositional Defiant Disorder10. Preliminary evidence suggests that the program’s positive effects may last through adolescence11, including reductions in antisocial behavior and improvements in academic outcomes12.

IY helps parents parent more positively and warmly. The program also helps parents set effective limits and reduces spanking, harsh discipline, and criticism1. The IY parent training program is especially effective for parents of young children13. IY participation improves parenting practices among parents with a history of child maltreatment5. Teachers who undergo IY training offer more praise and encouragement, and do not harshly punish or criticize their students as often as non-participating peers. Students of IY-trained teachers behave better and become more academically engaged than non-participating peers; young children also gain more school readiness skills1, 6.

To implement the program successfully, IY developers recommend choosing group trainers with applicable education and experience, providing ongoing mentor support and peer support for trainers and teachers, adhering to the program’s prescribed protocols, sequence, and session length14, and extending consultation and expert coaching for trainers beyond the standard 3-day sessions15.

The IY curriculum costs $425 to $1,970 per training program16.

How could this strategy impact health disparities? This strategy is rated likely to decrease disparities.
Implementation Examples

IY has been translated into many languages and is being used in over 20 countries. As of 2016, there are 21 certified trainers, 9 trainers in the certification process, and over 16,600 trained IY group leaders across the United States16.

Implementation Resources

IY - The Incredible Years (IY). Parents, teachers, and children training series.


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1 Blueprints - Center for the Study and Prevention of Violence (CSPV). Blueprints for healthy youth development.

2 YG-IY - (YG), Interagency Working Group on Youth Programs (IWGYP). The Incredible Years (IY).

3 Menting 2013 - Menting ATA, Orobio de Castro B, Matthys W. Effectiveness of the Incredible Years parent training to modify disruptive and prosocial child behavior: A meta-analytic review. Clinical Psychology Review. 2013;33(8):901-913.

4 Perrin 2014 - Perrin EC, Sheldrick RC, McMenamy JM, Henson BS, Carter AS. Improving parenting skills for families of young children in pediatric settings: A randomized clinical trial. JAMA Pediatrics. 2014;168(1):16-24.

5 Hurlburt 2013 - Hurlburt MS, Nguyen K, Reid J, Webster-Stratton C, Zhang J. Efficacy of the Incredible Years group parent program with families in Head Start who self-reported a history of child maltreatment. Child Abuse & Neglect. 2013;37(8):531-543.

6 Hutchings 2013 - Hutchings J, Martin-Forbes P, Daley D, Williams ME. A randomized controlled trial of the impact of a teacher classroom management program on the classroom behavior of children with and without behavior problems. Journal of School Psychology. 2013;51(5):571-585.

7 PPN - Promising Practices Network (PPN). On children, families and communities.

8 Mulqueen 2015 - Mulqueen JM, Bartley CA, Bloch MH. Meta-analysis: Parental interventions for preschool ADHD. Journal of Attention Disorders. 2015;19(2):118-124.

9 Presnall 2014 - Presnall N, Webster-Stratton CH, Constantino JN. Parent training: Equivalent improvement in externalizing behavior for children with and without familial risk. Journal of the American Academy of Child & Adolescent Psychiatry. 2014;53(8):879-887.e2.

10 Hobbel 2013 - Hobbel S, Drugli MB. Symptom changes of oppositional defiant disorder after treatment with the Incredible Years Program. Nordic Journal of Psychiatry. 2013;67(2):97-103.

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

12 Scott 2014 - Scott S, Briskman J, O’Connor TG. Early prevention of antisocial personality: Long-term follow-up of two randomized controlled trials comparing indicated and selective approaches. American Journal of Psychiatry. 2014;171(6):649-657.

13 Pidano 2015 - Pidano AE, Allen AR. The Incredible Years series: A review of the independent research base. Journal of Child and Family Studies. 2015;24(7):1898-1916.

14 Webster-Stratton 2011a - Webster-Stratton C, Reinke WM, Newcomer LL, Herman KC. The Incredible Years teacher classroom management training: The methods and principles that support fidelity of training delivery. School Psychology Review. 2011;40(4):509-29.

15 Webster-Stratton 2014 - Webster-Stratton CH, Reid MJ, Marsenich L. Improving therapist fidelity during implementation of evidence-based practices: Incredible Years program. Psychiatric Services. 2014;65(6):789-795.

16 IY - The Incredible Years (IY). Parents, teachers, and children training series.