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Publication Bias in Antipsychotic Trials: An Analysis of Efficacy Comparing the Published Literature to the US Food and Drug Administration Database

Figure 3

Forest plot of mean weighted effect size (Hedges's g) values by drug and data source.

The figure is sorted according to the effect size point estimates derived from the FDA data; these are shown with gray-filled squares. The point estimates derived from the corresponding journal articles are shown with open circles. Horizontal lines indicate 95% confidence intervals around the effect size point estimates. The right-hand column shows the percent differences between the FDA-based and the journal-based effect size point estimates. (These percent differences are based on estimates accurate to three decimal places, while the estimates shown are rounded to two decimal places.) The differences ranged from −4% to +20%, depending on the drug. For the entire drug class (labeled “overall antipsychotics”), publication bias increased apparent effect size by 8%. To provide context, previously published data on antidepressants [8] are shown at the bottom in gray. Note that the 8% increase with antipsychotics is much less than the 32% increase with antidepressants [8]. Also, the journal data show only a 16% advantage in effect size for antipsychotics over antidepressants (from 0.41 to 0.48), while FDA data reveal a much larger advantage (42%, from 0.31 to 0.44).

Figure 3