Links to the publications discussed:
Cochrane statement
‘Effectiveness trials (pragmatic trials) measure the degree of beneficial effect under “real world” clinical settings.’
It’s worth noting Howick’s 2022 review ‘Most healthcare interventions tested in Cochrane Reviews are not effective according to high-quality evidence: a systematic review and meta-analysis’
When Carl says, ‘This point confuses the issue of efficacy with effectiveness.’ you can refer to A Primer on Effectiveness and Efficacy Trials.
and to the results from the review on physical interventions:
‘Wearing masks in the community probably makes little or no difference to the outcome of influenza‐like illness (ILI)/COVID‐19 like illness compared to not wearing masks (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.84 to 1.09; 9 trials, 276,917 participants; moderate‐certainty evidence.’
Open season on mask evidence