Evaluation Library

Our aim is to provide youth justice professionals with accessible, relevant and objective information about the range of programmes in use across the youth justice system. The Evaluation Library is the YJB's collection of appraised youth justice interventions. The strength of the evidence has been evaluated and is classified into one of four categories based on the methods used:

  • No Classification
  • Level 1
  • Level 2
  • Level 3

These ratings may help inform a user’s decision of whether to adopt the practice.

Library Classification Levels

No Classification:

This is for those awaiting classification.

Level 1 – Theory of effectiveness

This classification level articulates what an intervention aims to do and how it relates to youth justice outcomes such as reducing offending and reoffending, reduction in first-time entrants, and reducing the number of young people in custody.

In these articles, there may not yet be any clear evidence of impact. The intervention should have an underpinning ‘theory of change’.

Level 2 – Preliminary evidence of effectiveness

Interventions at this level meet the Level 1 but also include evidence of the impact of the intervention. This will probably comprise a pre/post measure on key outcomes: a robust comparison group is not essential for inclusion at this level.

The evidence within these papers also includes clear description of the context in which the approach/intervention operates.

Level 3 – Robust evidence of effectiveness

Level 3 provides the most robust examples of evidence. These evaluated interventions are distinguished from those at Level 2 by the ability to say with greater confidence that the approach/intervention is likely to have produced the observed.  This may mean that alternative explanations for positive changes can be rules out.

More details of the categorization used are provided in Standards of Evidence (please note the classification used will be revised shortly following the publication of the new Magenta book).  

The Magenta Book published 01/04/2020 is the recommended central government guidance and presents standards of good practice in conducting evaluations.

The YJB welcomes new additions to its ‘Evaluation Library’. Please email your evidenced interventions to effectivepractice@yjb.gov.uk along with your rationale for inclusion.

Summary : This programme has been developed to support children who have exhibited agressive behaviour. Classification: Level 2 Age: 10-17 Sex: n/a Cost: Yes     Aim: Support children who have exhibited aggressive behaviour Support children to reduce some of their violent/aggressive incidents     Description:Aggression Replacement Training is a programme which is made up of three core areas; SkillStreaming…
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