Shechtman 2010.

Methods	Cluster‐randomised trial of group trauma therapy vs wait list
Participants	Included (n = 164) Elementary school students in Israel 9 to 14 years of age screened for post‐traumatic reactions with the Child Post‐Traumatic Stress Reaction Index (cutoff score 12). Female: 112 (68%). Most children were Jewish (82%), and all other participants were Arabic Excluded Not stated Setting Elementary and secondary schools in Israel, 2006 to 2007
Interventions	Group trauma therapy (n = 98) Treatment used activities and therapeutic games aimed at enhancing expression and exploration of feelings in a group context of mutual support over 10 sessions. Eighteen treatment groups were included: 5 for war‐related trauma, 7 for loss and divorce and 6 for mixed traumas Wait list (n = 66) Control children received treatment after the experimental group was terminated Therapists Therapists were 18 school counsellors who received training in the expressive‐supportive therapy modality over 56 hours and received group supervision .
Outcomes	PTSD symptoms Scale: Child Post‐Traumatic Stress Reaction Index (20‐item) Rater: child/adolescent Anxiety Scale: Revised Children’s Manifest Anxiety Scale (37‐item) Rater: child/adolescent When Post therapy
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Cluster‐randomised by group, but how this was done was not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants (performance bias	High risk	Participants probably were aware of whether they were in the wait list control or active group
Blinding of outcome assessment (detection bias) All outcomes	High risk	Observers were not blinded
Incomplete outcome data (attrition bias) All outcomes	High risk	Loss to follow‐up: 17%
Selective reporting (reporting bias)	Low risk	All outcomes appear to have been reported
Other bias	Low risk	No other bias was apparent