Table 2

Data extraction

Categories
Population
AgeChildren’s ages were grouped by UK school ‘Key Stage’ categories79:
  • 5–7 years, corresponding to Key Stage 1 (KS1)

  • 8–11 years, corresponding to Key Stage 2 (KS2)

  • Including both KS1 and KS2 participants

PopulationParticipants were grouped into clinical, at-risk and healthy (based on the coding system indicated, selective, universal)80
  • Clinical; those identified as have a disease/disorder

  • At-risk; those identified as at risk of a health condition

  • Healthy; universal interventions targeting a whole population groups

Condition/behaviourThe condition or behaviour that the intervention was designed to target was grouped into
  • Lifestyle; day-to-day health behaviours such as diet, exercise, smoking

  • Neurodevelopmental

  • Social-emotional-behavioural

  • Physical symptom management/treatment

Intervention
RecipientsCodes were used to note whether the intervention was delivered directly to the child, via a parent-proxy or both
ModalityThe type of intervention (modality) was coded as either a First, Second or Third Wave11 behavioural intervention
SettingCategories for setting were inductively developed:
  • School

  • Clinical/health

  • Community

Mode of deliveryCategorised in accordance with elements of the mode of delivery taxonomy78:
  • Face-to-face. If the intervention was face–face, we documented whether this was delivered on an individual basis or in group setting

  • Paper based

  • Digital

Techniques of deliveryInductive categories were developed for techniques of delivery:
  • Interactive techniques: play, arts, story and/or game-based techniques

  • Reward-based techniques

ComplexityInterventions were classed as complex if they contained multiple components76
EffectivenessTo provide an overview of the effectiveness of interventions, the effect of the intervention on the specified primary outcome was extracted. To identify the primary outcome, the original paper, any published protocols and trial registries were reviewed. If a primary outcome was specified, the following categories were used:
  • ‘Promising’, if there was improvement in the primary outcome in the intervention group compared with the control, as reported by the authors

  • ‘Not promising’, if there was no improvement in the primary outcome in the intervention group compared with the control, as reported by the authors

  • If no primary outcome was specified, we categorised this as

  • ‘Unable to assess effectiveness’