Systematic literature review and meta-analysis of the relationship between adherence, competence and outcome in psychotherapy for children and adolescents

The extent to which therapist adherence to guidelines and clinician skill or competence may play a role in the prediction of therapeutic outcomes remains inconclusive. This systematic literature review and meta-analysis considers whether adherence or competence predicts youth outcome in child and adolescent psychotherapy, and whether there are any identifiable factors which moderate the strength or direction of this relationship. A systematic literature search identified 35 studies in 52 papers. The studies contained 29 effect sizes for the relationship between adherence and outcome, while nine effect sizes were extracted for competence, and a further five effects measured a composite of adherence and competence constructs, referred to as fidelity in this report. The meta-analysis indicated a small but significant relationship between therapist adherence and outcome, although the small size of effect suggests that outcomes are likely to be more strongly associated with factors other than adherence. No significant relationship was identified between competence or composite fidelity and outcome. Although variance was observed in effect sizes, no significant moderation by client group, intervention type, or implementation measure informant was identified. Further study is needed to understand the specific circumstances under which adherence and outcome are related. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00787-018-1265-2) contains supplementary material, which is available to authorized users.