Third, PRS effect size estimates from the model that uses the incomplete phenotypic PC as a correction for collider bias approach the true value of 0.1 as the proportion of complete data included in the PC increases. Note that the estimates from simulation model A3 (~PRS+Env+IncompletePC; shown in green) are summarized best by a positive slope that approaches 0.1. This suggests that PCA will provide a better correction for collider bias when more of the confounding data is measured. The relationship between the proportion of confounding data that is measured and the magnitude of the correction varies as a function of the magnitude of the rGE parameter (the magnitude of collider bias). Here, we present average change in Model A3 in four bins for the proportion of confounding data that is measured in the correction: (1) 10% - 25%, (2) 26% - 50%, (3) 51% - 75%, and (4) 76% - 99%. When rGE = 0.1 and confounder correlations range between 0.05-0.1 the model A3 PRS effect increases by 5%, 14%, 25%, and 37% for bins 1 through 4, respectively.
