Figure 2. Funnel Plot Examining Publication Bias in Omega-3 Fatty Acid Trials to Treat Major
Depression
This funnel plot depicts the effect size of trials versus their inverse standard error. Published
trials are depicted as circles and are shaded from darkest to lightest based on their
publication year. White squares represent potentially missing trials that were imputed based
on the trim-and-fill method. The red line represents the point estimate for omega-3 treatment
effects based on published trials (SMD=0.11, 95% CI: -0.04, 0.26), p=0.14). The red curves
bracket the 95% CI for the expect results of trials given this estimated underlying effect size.
The black vertical line represents the new point estimate for the effect size of omega-3 fatty
acids when publication bias is adjusted for using the trim-and-fill method. (SMD=0.01, 95%
CI: -0.13, 0.15). Abbreviations: SMD=standardized mean difference, CI=confidence
interval.