Palermo 2009.

Methods	RCT. 2 arms. Assessed at pretreatment and post‐treatment
Participants	End of treatment: N = 44 Start of treatment: N = 48 Sex: 35 F, 13 M Mean age: 14.8 (SD 2.0) Source: medical centre in the Pacific Northwest USA Diagnosis: headache (25% of the sample), abdominal pain (50% of the sample), or musculoskeletal pain (25% of the sample) Mean years of pain: 30 months
Interventions	"Internet‐delivered family cognitive‐behavioural therapy" "Wait‐list control group"
Outcomes	Primary pain outcome: clinical reduction in headache frequency (headache analysis) and mean pain intensity (mixed chronic pain conditions analysis) Primary disability outcome: Child Activity and Limitations Interview Primary depression outcome: Revised Child Anxiety and Depression Scale Primary anxiety outcome: none Primary satisfaction outcome: treatment acceptability and satisfaction Measures reported: daily pain intensity NRS (averaged over 7 days) usual pain intensity over the past month NRS Child Activity Limitations Interview Revised Child Anxiety and Depression Scale Protect subscale from Adult Responses to Children's Symptoms treatment acceptability and satisfaction
Notes	Funding source: National Institutes of Health/National Institute of Child Health and Human Development (Grant HD050674; PI: Palermo) and by a grant from the Doernbecher Foundation Declarations of interest: authors have no conflicts of interest
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"A fixed allocation randomisation scheme was used. Specifically, we used blocked randomisation with blocks of 10 to assign participants to the two treatment conditions during the course of randomisation. An online random number generator was used to produce the blocked randomisation. Group assignments were identified by ID number in sealed envelopes. Following completion of all pre‐treatment assessments, a research coordinator opened the sealed envelope to reveal the group assignment." Comment: probably done
Allocation concealment (selection bias)	Low risk	"A fixed allocation randomisation scheme was used. Specifically, we used blocked randomisation with blocks of 10 to assign participants to the two treatment conditions during the course of randomisation. An online random number generator was used to produce the blocked randomisation. Group assignments were identified by ID number in sealed envelopes. Following completion of all pre‐treatment assessments, a research coordinator opened the sealed envelope to reveal the group assignment." Comment: probably done
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No description found in text Comment: probably not done
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Measures completed at home and submitted online or mailed back
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Attrition completely reported; significant differences between completers and non‐completers were not reported
Selective reporting (reporting bias)	Low risk	Data were fully reported