Estimates of hSNP2 and SNP-based coheritability from the linear model are on the case-control scale and so depend partly on the proportion of cases and controls in the sample. Transformation to the liability scale allowed benchmarking of hSNP2 to estimates of heritability from family studies, and the transformation accounts for the proportion of cases in the sample and depends on the assumed disorder risk (K). The appropriate choice of K depends on the definitions of both the phenotype (including ascertainment strategy) and the population, which might differ between cohorts. We considered lower and upper bounds for K in Table 1 to cover the range of possible values. rg SNP estimates are independent of scale and hence are not dependent on the choice of K.
