Figure 3 :Posterior odds that a result is true, assuming risk alleles with a frequency of 10% and a genotype relative risk (GRR) of 1.2 and a multiplicative model This figure indicates the posterior odds that a result is true (plotted on a log scale on the y-axis) against the signifi cance of the result (plotted as the negative log of the P-value on the x-axis). Five sample sizes are listed in the legend; in each, the number of cases and controls are equal. The 200 line thus indicates the posterior odds for a study involving 200 cases and 200 controls, and so on. Power was calculated using the online genetic power calculator. Reprinted from Brain, Vol. 131, 3118-31, Copyright (2008), with permission from Oxford University Press.