Fig 2 shows contour plots for the power per truly associated SNP and R2 for a setting with 50 studies, with a total sample size of 250,000 individuals, for 1k causal SNPs and 100k SNPs in total, for various combinations of hSNP2 and CGR. The figure shows a symmetric response of both power and R2 to CGR and hSNP2. For instance, when hSNP2=25% and CGR = 0.5 across all studies, the power is expected to be around 34% and the R2 3.0%. When these numbers are interchanged (i.e., hSNP2=50% and CGR = 0.25), similarly, the power is expected to be 35% and the R2 2.9%. Hence, in terms of both R2 and power, a low heritability can be compensated by a high CGR (e.g., by means of homogeneous measures across studies) and a low CGR can be compensated by high heritability. When either CGR or heritability is equal to zero, both power and R2 are decimated in the multi-study setting. However, when both are moderately low but still substantially greater than zero, neither power nor R2 are completely diminished.
