Statistical analysis
trauma
REGRESSION
We aimed to recruit 217 participants (93 per treatment group and 31 for the waiting list) to have 80% power to detect an effect size of Cohen's Statistical analyses were pre-specified in the statistical analysis plan before the end of the trial and then followed (All models used restricted maximum likelihood estimation and an unstructured covariance matrix. Q–Q plots indicated that the normality of residuals assumption was met for all models. Standardised between-group effect sizes (The primary analysis compared participants who were immediately allocated to iCT-PTSD and iStress-PTSD on PCL-5 scores at 13 weeks. Several sensitivity analyses were performed. First, we explored variables related to missing data in the primary outcome at 13 weeks, including any significant predictors in the analysis. Second, we did multilevel multiple imputation of missing data with the mice R package, using all available baseline variables. Third, only participants who had received at least a minimum dose of therapy that can be expected to have clinical benefits were analysed, defined as completing core procedures relating to (1) rationale and psychoeducation, (2) activities in everyday life, and (3) at least one core technique addressing trauma memories in iCT-PTSD or one core stress-management technique in iStress-PTSD, respectively (Further linear mixed-effects regression models analyses tested whether any demographic, clinical, or trauma characteristics influenced the size of the difference in the primary outcome between the treatments (moderator analyses; 