In this section, we expand on W&H's results by considering a scenario where the effect size matters. We slightly changed the scenario of W&H, but still compared the same two approaches. Again, the population was normally distributed, standard deviation equaled 1, and each primary study had a sample size of 50. However, the population mean equaled 0 (no effect), rather than 0.3 as in W&H's scenario. Moreover, we introduced a different stopping rule: it was assumed scientists stopped investigating the effect when they rejected the null hypothesis that the population effect is at least small (H0: d = μ≥.2) using the results of the meta-analysis on all published studies. We believe it is safe to assume scientists are no longer interested in studying an effect when it is “smaller than small”. Again we applied random-effects meta-analysis in both approaches.
