nominally significantP < 0.05
46 Evaluation of excess significance bias The excess statistical significance test was used to assess whether the number of observed ( O ) studies with nominally significant results (“positive” studies, P < 0.05) in the published literature was different from the expected ( E ) number of studies with statistically significant results. 47 The E number of statistically significant studies in each meta-analysis was calculated from the sum of the statistical power estimates for each component study using an algorithm from a non-central t distribution.