Skip to main content
. Author manuscript; available in PMC: 2014 Jul 1.
Published in final edited form as: Neurosci Biobehav Rev. 2012 Oct 23;37(6):1162–1171. doi: 10.1016/j.neubiorev.2012.09.008

Figure 6. Funnel Plot Depicting Publication Bias in Alpha-2 Agonist Trials in the Treatment of Tics.

Figure 6

Visual inspection of the funnel plot and the meta-regression of the association between effect size and sample size demonstrated significant evidence of publication bias (α=−0.0012 (95%CI: −0.0021–(−0.0003)), z=−2.65, p=0.008). When publication bias was adjusted for using the Duval and Tweedie trim-and-fill method, alpha-2 agonists still demonstrated a significant benefit compared to placebo (SMD=0.18 (95%CI: 0.03–0.33)).