Assuming the marginal liabilities are distributed as a standard normal, the threshold for exhibiting trait is where is the population prevalence. The genetic effects are now taken to act on liability, and for small effects a linear transformation to the corresponding effect on the observed trait may be obtained as [30] (11)Given the genetic variance-covariance matrix on the liability scale, the statistical properties of the polygenic score may now be calculated as before, but substituting for and for throughout, and using as the sampling variance of .
