I have heard that it is now possible to run a model estimating genetic and environmental effects with twin data that includes separate variables with binary and continuous (or ordinal?) coding.
I have been running a thresholds model with age and sex as covariates (which I will attach) and I would like to include the same behavioural measures from different data sets in the one model.
Two different scales have been used to collect this information (binary and continuousish), and I want to equate the A, C and E paths across datasets with the differing scales. I have been told this will necessitate the inclusion of a group for each dataset. But I am also unsure how to do this.
Is this possible and can you help? - and forgive me if I am missing some important technical detail.