Publication Bias

Publication bias is the systematic tendency for studies with positive, statistically significant results to be published more frequently than studies with null or negative findings. This creates a distorted evidence base where supplements appear more effective than they truly are. Publication bias is particularly problematic in supplement research, where industry funding may influence publication decisions. Funnel plot asymmetry, Egger's test, and trim-and-fill analysis are methods to detect and adjust for publication bias in meta-analyses. Trial registries (ClinicalTrials.gov) help identify unpublished studies.