OE Journal

ORIGINAL ANALYSIS

2 Simple Tips to Detect Publication Bias

Publication bias occurs when studies with unfavourable or non-significant results never make it to publication, creating a misleading picture in a meta-analysis. A quick way to assess this risk is through a funnel plot, which displays each study’s effect estimate against its precision. When results form a balanced, inverted funnel, bias is less concerning. When the plot shows gaps—often missing small, imprecise studies with negative findings—an asymmetric shape emerges, signalling potential publication bias and an overestimation of treatment benefits. Although useful, funnel plots require a sufficient number of studies and can be influenced by factors other than bias, making interpretation cautious rather than definitive.