Publication Bias
The tendency for studies with positive or statistically significant results to be published more frequently than studies with negative or inconclusive results. Publication bias can distort the overall evidence base for a compound, making treatments appear more effective than they truly are.
Technical Context
Publication bias distorts the evidence base because: positive trials are 2-3× more likely to be published than negative trials, positive trials are published faster (median 4-5 years for positive vs 6-8 years for negative), and positive trials are more likely to appear in high-impact journals. Detection methods: funnel plot visual inspection (asymmetry suggests bias — missing small negative studies in the lower-left corner), Egger's regression test (formal statistical test for asymmetry), and Begg's rank correlation test. Mitigation strategies: trial registration (ensures awareness of all conducted trials, including unpublished ones), results reporting mandates (FDAAA 801 requires posting results to ClinicalTrials.gov), and journals accepting registered reports (peer review of methods before results are known). For peptide compounds, publication bias is particularly concerning for research compounds where a small number of publications from a limited number of groups may overrepresent positive findings.