Basoglu 2005.

Methods	Randomised controlled trial
Participants	59 earthquake survivors in Turkey with DSM‐IV PTSD (50 women, 9 men)
Interventions	Single session of CBT (n = 31) vs waitlist control (n = 28)
Outcomes	CAPS, TSSC, FAQ, BDI, WSA
Notes	Treatment delivered by psychologists trained in the approach. Treatment adherence was measured.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Random allocation was conducted according to a computer‐generated randomization list. Blocking was used to ensure approximately equal cell sizes."
Allocation concealment (selection bias)	Low risk	Quote: "The participants were recruited into the study by four independent assessors, who did not have access to the random assignment schedule. The latter was implemented by the project coordinator, who did not take part in the assessments at any stage during the trial."
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "As a result of case attrition after week 6, two types of end‐point imputation analyses were carried out. First, the treatment effects were examined at each follow‐up, carrying forward the scores of the non‐improved non‐completers at their last available assessment to subsequent follow‐up points. As this procedure did not involve the improved non‐completers and assumed that the non‐improved non‐completers would have remained non‐improved had they stayed in the study, it led to a conservative analysis of the treatment effects." Comment: participants who did not have at least one follow‐up after treatment were replaced. Eight individuals dropped out of treatment group and 2 from waitlist. No reasons were given.
Selective reporting (reporting bias)	Low risk	Comment: All specified and expected outcomes appear to have been reported.
Other bias	Low risk	Comment: Baseline demographics are poorly reported. Groups were reported to be similar in every baseline variable but gender (only 1 man in WL group vs 8 in the treatment group).
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: Participants were aware of their allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote "The assessments were conducted by four independent assessors (three psychologists and one psychiatrist), who were blind as to the participants’ experimental condition. A Blindness Integrity Assessment Form was used to elicit information about whether assessor blindness was maintained at the second assessment and the assessor’s guess as to the study participant’s experimental condition."