In this paper by Noetel and colleagues (BMJ 2024;384:e075847, doi:10.1136/bmj-2023-075847, published 14 February 2024), the following sentence should have been removed to reflect a change in the standard deviation used to calculate effect sizes. “Using National Institute for Health and Care Excellence guidelines,42 we standardised change scores for different depression scales (eg, Beck depression inventory, Hamilton depression rating scale) using an internal reference standard for each scale (for each scale, the average of pooled standard deviations at baseline) reported in our meta-analysis.”
Effects for each arm were instead standardised using the standard deviation at baseline.1 This decision improved comparability of effect sizes to existing reviews and did not lead to material changes in the findings.