Gold Standard Synthesis
Cochrane Collaboration, founded in 1993 and named after epidemiologist Archie Cochrane, represents the gold standard for systematic review conduct. Cochrane reviews combine rigorous methodology with unprecedented transparency. All reviews are freely available online.
Cochrane reviews employ pre-registered protocols published before conducting reviews. This prospective registration prevents protocol changes motivated by preliminary findings. Reviewers commit to specific populations, interventions, comparators, outcomes, and analysis methods before examining data.
Cochrane reviews restrict inclusion to high-quality randomised controlled trials, excluding observational studies. The GRADE approach rates evidence quality on four levels: high, moderate, low, or very low. GRADE explicitly considers trial limitations, inconsistency, directness, precision, and publication bias.
Plain language summaries make findings accessible. Living reviews continuously monitor literature for new trials, updating conclusions dynamically. Cochrane reviews undergo rigorous dual-reviewer quality control.
Cochrane reviews have limitations. Restriction to published trials may miss grey literature. For novel areas without many trials, reviews may conclude insufficient evidence. Conservatism sometimes produces 'no evidence' when absence of evidence is conflated with evidence of absence.