The general linear model for gene effects and G × E is fitted to the liabilities and test scores derived from the item responses to test the main effects and interactions of the candidate genes and environments simulated under various “true” configurations of their effects on liability. Parameter estimates and their sampling errors are recovered and t tests compared for the various types of measurement to assess the impact of different approaches to measurement on the outcome of tests for non-additive effects of genes and environment (epistasis and G × E) under various combinations of “true” genetic model and mode of assessment.
