Studies with positive or notable results are more likely to get published than null ones.
Publication bias occurs when the likelihood of a study being published, and how quickly, depends on the direction or significance of its findings rather than its methodological quality. Because null or negative results are more likely to sit in a file drawer, published literature can overstate the true effect of an intervention. This matters directly for evidence appraisal: meta-analyses and reviews built on published studies alone may need funnel-plot or similar checks to assess whether missing null studies are skewing conclusions.
This guide was auto-drafted and is pending editorial review.