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Incredible Years Preschool

Evidence rating
Cost rating
Review: Foundations for Life, July 2016

The Incredible Years (IY) Preschool basic programme is for parents with concerns about the behaviour of a child between the ages of three and six.

Parents attend 18 to 20 weekly group sessions where they learn strategies for interacting positively with their child and discouraging unwanted behaviour. Two facilitators (QCF-7/8) lead parents in weekly two-hour group discussions of mediated video vignettes, problem-solving exercises and structured practice activities addressing parents’ personal goals.

The Advanced add-on to Incredible Years Preschool includes a component that seeks to improve children’s outcomes by improving the quality of interparental relationships (IPR).

EIF Programme Assessment

Evidence rating

Incredible Years Preschool has evidence of a long-term positive impact on child outcomes through multiple rigorous evaluations.

What does the evidence rating mean?

Level 4 indicates evidence of effectiveness. This means the programme can be described as evidence-based: it has evidence from at least two rigorously conducted evaluations (RCT/QED) demonstrating positive impacts across populations and environments lasting a year or longer.

What does the plus mean?

The plus rating indicates that a programme’s best evidence is level 4 standard, and there is at least one other study at level 4, and at least one of the level 4 studies has been conducted independently of the programme provider.

Cost rating

A rating of 2 indicates that a programme has a medium-low cost to set up and deliver, compared with other interventions reviewed by EIF. This is equivalent to an estimated unit cost of £100–£499.

Child outcomes

According to the best available evidence for this programme's impact, it can achieve the following positive outcomes for children:

Enhancing school achievement & employment

Improved reading - based on study 2

Preventing crime, violence and antisocial behaviour

Improved behaviour on all measures - based on study 1, study 2, study 3

Less defiant behaviour - based on study 2

This programme also has evidence of supporting positive outcomes for couples, parents or families that may be relevant to a commissioning decision. Please see About the evidence for more detail.

Incredible Years Preschool

Key programme characteristics

Who is it for?

The best available evidence for this programme relates to the following age-groups:

  • Preschool

How is it delivered?

The best available evidence for this programme relates to implementation through these delivery models:

  • Group

Where is it delivered?

The best available evidence for this programme relates to its implementation in these settings:

  • Children's centre or early-years setting
  • Community centre
  • Out-patient health setting

The programme may also be delivered in these settings:

  • Home
  • Primary school

How is it targeted?

The best available evidence for this programme relates to its implementation as:

  • Targeted indicated

Where has it been implemented?

United Kingdom, United States

UK provision

This programme has been implemented in the UK.

UK evaluation

This programme’s best evidence includes evaluation conducted in the UK.

Spotlight sets

EIF includes this programme in the following Spotlight sets:

  • Improving interparental relationships
Incredible Years Preschool

About the programme

What happens during delivery?

How is it delivered?
  • Incredible Years Preschool is delivered by two IY co-leaders to groups of approximately 12 families in 20 sessions of around two hours each.
What happens during the intervention?
  • During the sessions, parents practise child-directed play skills that build positive relationships and attachment; strengthen more nurturing parenting using social, emotion and persistence coaching methods; encourage school readiness skills and early problem-solving skills; establish predictable routines and rules; provide incentives for positive behaviour; and reduce behaviour problems.
  • Parental social support is strengthened by weekly facilitator calls, parent-buddy calls and group process methods.
  • IY Preschool can be combined with Incredible Years Advanced for families with more complex issues. Advanced is a 10 to 12-week add-on component that covers anger and depression management, building support networks, effective problem-solving for couples and has teacher and family meetings.

What are the implementation requirements?

Who can deliver it?
  • It is delivered by two IY co-leaders with QCF-7/8 qualifications who may be a psychologist, social worker, nurse or physician.
What are the training requirements?
  • The practitioners have 24 hours of training each. Booster training of practitioners is recommended.
How are the practitioners supervised?
  • Supervision is shared between the host agency and the programme developer and is provided by two supervisors with QCF-7/8 qualifications.
What are the systems for maintaining fidelity?
  • Fidelity monitoring
  • Face-to-face training
  • Accreditation or certification process
  • Supervision
Is there a licensing requirement?

Yes, there is a licence required to run this programme.

How does it work? (Theory of Change)

How does it work?
  • The Incredible Years model assumes that some parenting behaviours inadvertently encourage unwanted child behaviour.
  • Parents will learn more effective strategies for dealing with unwanted child behaviour when they have opportunities to practise and perceive themselves as effective in using them.
  • Effective parenting strategies help the child learn how to better manage his or her emotions and behaviour.
  • In the longer term, the child will get along better with others and there will be a reduced likelihood of antisocial or criminal behaviour.
Incredible Years Preschool

About the evidence

IY Preschool has evidence from three RCTs, all of which were conducted in the UK.

Study 1

Citation: Hutchings et al (2007)
Design: RCT
Country: United Kingdom
Sample: 153 families attending Sure Start centres in Wales
Timing: -
Child outcomes: Improved behaviour on all measures
Other outcomes: Reduced symptoms of depression
Reduced levels of stress
Reduced critical parenting
Increased positive parenting

Hutchings, J., Bywater, T., Daley, D., Gardner, F., Whitaker, C., Jones, K., Eames, C., & Edwards, R.T., (2007). Parenting intervention in Sure Start services for children at risk of developing conduct disorder: pragmatic randomised controlled trial, BMJ, 334, doi:10.1136/bmj.39126.620799.55.

Available at">

Study 2

Citation: Scott et al (2001) and Scott et al (2014)
Design: RCT
Country: United Kingdom
Sample: 141 families referred to CAMHS for child behavioural problems and 94 participants from the original study
Timing: -
Child outcomes: Improved reading
Improved behaviour on all measures
Less defiant behaviour
Other outcomes: Reduced inappropriate commands
Warmer expressed emotion

Scott, S., Spender, Q., Doolan, M., Jacobs, B., & Aspland, H. (2001). Multicentre controlled trial of parenting groups for childhood antisocial behaviour in clinical practice. BMJ, 323, 1-7.

Scott, S., Briskman, J., & O’Connor, T. (2014). Early Prevention of Antisocial Personality: Long-Term Follow-Up of Two Randomized Controlled Trials Comparing Indicated and Selective Approaches. American Journal of Psychiatry, 171, 649- 657.

Available at

Study 3

Citation: Gardner et al (2006)
Design: RCT
Country: United Kingdom
Sample: 76 families with a child aged six or younger
Timing: -
Child outcomes: Improved behaviour on all measures
Other outcomes: Increased sense of competence
Increased positive parenting strategies
Decreased negative parenting strategies

Gardner, F., Burton, J., & Klimes, I. (2006). Randomised controlled trial of a parenting intervention in the voluntary sector for reducing child conduct problems: outcomes and mechanisms of change. Journal of Consulting and Clinical Psychology, 47, 1123-1132.

Available at

Other studies

The following studies were identified for this programme but did not count towards the programme's overall evidence rating. A programme receives the same rating as its most robust study or studies.

Additional studies are available at

Published March 2017   |   Last updated February 2019