Problematic Evidence

The protocol defines problematic evidence as retracted clinical trials and meta-analyses that included retracted trials. The study assumes all retracted trials are fraudulent as a pragmatic choice, even though not all retractions are due to fraud. Retracted trials are treated as only a visible subset of all problematic trials. Fraudulent or unreliable trials can contaminate evidence syntheses and influence guideline recommendations. Limiting the study to retracted trials and reviews that included them is expected to underestimate the true impact.