Julkistusbias

Julkistusbias, or publication bias, is a systematic distortion in the scientific record that occurs when studies with statistically significant or favorable results are more likely to be published than studies with inconclusive or null results. The bias can affect any field and can occur at multiple stages of the research lifecycle, from study design and data analysis to submission, editorial decision, and final publication. In practice, this means the published literature may overrepresent positive findings and underrepresent negative or inconclusive ones.

Mechanisms of julkistusbias include selective submission by researchers who expect easier publication for significant results; editorial and reviewer preferences; language bias toward positive results in international journals; time lag bias where significant findings are published earlier; and outcome reporting bias where only favorable outcomes are reported.

Consequences include distorted effect size estimates in meta-analyses, overestimation of interventions’ effectiveness, inflated claims, and replication difficulties. This can mislead clinicians, policymakers, and researchers, and may waste resources.

Detection and assessment employ statistical tools such as funnel plots, Egger’s test, trim-and-fill methods, and analyses like p-curve and p-uniform, as well as systematic reviews that account for gray literature. Preregistration of study protocols and registered reports reduce opportunities for selective reporting. Encouraging data sharing and the publication of negative results also mitigates bias.

Efforts to reduce publication bias include journal policies that promote the acceptance of well-conducted studies regardless of outcome, trial registries that require the reporting of all results, and funder or institutional incentives aligned with transparent reporting.